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Francisco Afonso`s Thesis - index

1. 18 2 Headers veces RD pi CINE EE 19 3 Profiles and RTP Header Extension een 20 D 5 000 21 TABLE OF CONTENTS Vil E RTP CONTROL PROTOCOL RTCP eee 22 l Sender Report SR t eai Dai 24 2 Recerver Report RR s d ees e eek 27 3 Source Description 50 29 4 Goodbye BYE 32 F MUTTIMBDUIA IN RTP Mid ang OUR Mapa fn 33 G ANALYSIS OF SR AND RR REPORTS eee 33 H RTP PROFILES AND PAYLOAD FORMAT SPECIFICATIONS 34 1 Profile Specification Documents eee 34 2 Payload Format Specification 34 E SUMMARY 6 dete 35 IV JAVA MEDIA FRAMEWORK enne 37 Masc rtr t 37 B OVERVIEW qe 37 ARCHITECTURE 5 38 RTP SESSION MANAGER 0 2 nennen 42 1 RTP Streams m npe edo eee 42 pA RTP Participants 43 3 RTCP Source ESCH PUM croi Ep sint
2. public class RtpPlayerWindow extends PlayerWindow public RtpPlayerWindow Player player String title super player setTitle title public void Name String title setTitle title end of class PlayerWindow 186 package org web3d vrtp rtp import javax media rtp import javax media rtp event import javax media rtp rtcp import java util A class with some RTP utilities static methods author Francisco Afonso afonso cs nps navy mil version 1 0 public class RtpUtil Returns the participant username param part the Participant object return a string with the participant s username public static String getUsername Participant part X X X Vector sdeslist part getSourceDescription if sdeslist null return null SourceDescription des for int 11 0 ii lt sdeslist size 11 des SourceDescription sdeslist elementAt ii if des getType SourceDescription SOURCE_DESC_NAM return des getDescription LE return null 187 Returns the participant s username or his CNAM if no username is known param part the Participant object return string with the participant s username or CNAM X X BEN public static String getUsernameOrCNAME Participant part Strin
3. Clears all stats info on screen 57 private void clearAllData for int 33 0 jj 15 33 gText jj setText for int jj 0 jj 5 33 1 rText jj setText activeArea setText passiveArea setText feedbkArea setText streamChoice removeAll streamTable clear Clears all stream related stats private void clearStreamData for int jj 0 12 lt 5 4433901 rText jj setText feedbkArea setText 174 getItem longValue Disable user input components used after a session is started p private void disableInputs sessionText setEnabled false modifyPref setEnabled false selectBm setEnabled false Enable user input components used after a session is stoped y private void enableInputs sessionText setEnabled true modifyPref setEnabled true selectBm setEnabled true Returns the state of RtpMonitor Also exits the program if the duration is over Qreturn true if the monitor is active 2 public boolean isMonitoring if endDate compareTo new Date lt 0 System exit 0 return flgActive Creates a string with a fixed size starting by a given string and ending with blank spaces iparam strin the original string iparam size the final size of the returning s
4. import java io A Dialog to display and modify the program preferences lt P gt author Francisco Afonso afonso cs nps navy mil version 1 0 public class ModifyPreferences extends Dialog protected Checkbox recordBox partBox playBox protected Label intervalLabel intervalPresLabel endLabel viewerLabel protected TextField intervalText intervalPresText viewerText protected Choice endChoice private String strEndsIn 1 hour 2 hours 4 hours 8 hours 12 hours 24 hours 2 days 1 week Constructor lt P gt param parent the parent frame A public ModifyPreferences Frame parent super parent Preferences true setSize 260 280 setLayout null setBackground Color lightGray addWindowListener new CloseWindow partBox new Checkbox Send RTCP packets true partBox se partBox se add partBox tBounds 10 30 140 25 tBackground Col lor lightGray playBox new Checkbox Play incoming media true playBox setBounds 10 60 160 25 playBox recordBox new Checkbox Record statistics true recordBox setBounds 10 90 140 25 recordBox intervalLabel new Label Record Interval sec intervalLabel setBounds 10 120 120 25 add intervalLabel intervalText new TextField 30 0 intervalText setBounds 130 120 40 25 add
5. public class RtpHeader extends PduElement this SSRC will be used for all transmitted packets private static long mySSRC this variable contains the next sequence number of a transmitted packet private static int nextSequenceNumber static assigns a random integer to the SSRC mySSRC long Math random UnsignedInt MAX INT VALUE assign a random integer to the first sequence number nextSequenceNumber int Math random UnsignedShort MAX SHORT VALU Ld Identifies the version of RTP 2 bits RFC1889 defines the actual version as two 2 X public static final int VERSION 2 207 Padding is being performed at the DIS protocol level Therefore the padding bit is set to zero public static final int RTP_PADDING 0 The extension bit defines if the normal header will be by an extension header Not needed in this application and so set to zero x public static final int EXTENSION 0 Contains the number of contributing source identifiers followed in this header This is used only by mixers Set to zero public static final int RTP_CSRC_COUNT 0 This bit is used as a marker by a specific profile or application Not used so far Set to zero 27 public static final int RTP MARKER 0 The payload
6. Figure 3 2 RTP Header Extension Schulzrinne et al 99 The length field defines the number of 32 bit words of the header extension excluding the first one Therefore zero is a possible value Only a single variable length header extension can be appended to the RTP header D RTP SESSION ADDRESSING A session is an association among participants It is defined by two transport parameter pairs two network addresses plus corresponding port numbers One transport address is used for transmitting RTP packets and the other is used for RTCP packets The destination transport address pair may be the same for all participants when using multicast or may be different for each when using unicast For multicast UDP the multicast address for RTP and RTCP in a session must be the same the RTP port must be even and the RTCP port must be the next higher odd port number Multiple RTP sessions are distinguished by different port number pairs and or different multicast addresses 21 Some applications like audio and videoconferences require the use of two sessions one for audio and the other for video Distinct media types should not be carried in a single session because of the different timing and bandwidth requirements Figure 3 3 shows three different multicast conferences configurations Part a is a single media conference represented by a single session Part b and c represent two possible configurations for a conference wit
7. Updates the lists of active and passive participants public void showParticipants activeArea setText Vector aux mymgr getActiveParticipants Participant part for int ii 0 ii aux size 11 part Participant aux elementAt ii activeArea append RtpUtil getUsernameOrCNAME part n passiveArea setText aux mymgr getPassiveParticipants for int ii 0 ii aux size 11 part Participant aux elementAt 11 passiveArea append RtpUtil getUsernameOrCNAME part n Updates the stream statistics E public void showStreamStats if flgUpdateStreams return ReceiveStream dispStream null ReceiveStream stream ReceptionStats stats Participant part String display streamChoice removeAl1 streamTable clear Vector aux mymgr getReceiveStreams for int ii 0 ii aux size 11 171 gText 4 setText new Integer stats getBadRTPkts toString gText 5 setText new Integer stats getBadRTCPPkts toString gText 6 setText new Integer stats getMalformedSR toString gText 7 setText new Integer stats getMalformedRR toString gText 8 setText new Integer stats getMalformedSDES toString gText 9 setText new Integer stats getMalformedBye 2 gText 10 setText new Integer stats getLocalColls toString gText 11 setText new Integer stats getRemoteColls
8. modPrefDialog intervalPresText getText getSelectedIndex 36000001 disableInputs locator sessionText getText recInterval Double parseDouble presInterval Integer parseInt flgPart modPrefDialog partBox getState flgPlay modPrefDialog playBox getState flgRecord modPrefDialog recordBox getState SSRCtoShow 0 ndDate new Date new Date getTime endsInHours modPrefDialog endChoic if startSession stop setEnabled true addBm setEnabled true changeStream setEnabled true flgUpdateStreams true else start setEnabled true enableInputs e getSource stop flgActive false stop setEnabled false addBm setEnabled false monMgr close monMgr null mymgr null clearAllData changeStream setl Enabled true uts start set enableInp changeStream setEnab ed false flgUpdateStreams clearStreamData streamChoice setl 4 false ed true Enabled false changeStream 168 if if if if if H Fh H Fh H Fh H Fh H Fh H Fh if e getso modPrefDial modPrefDial urce modPrefDial modPrefDialog modifyPref setTitle Modify Preferences enableInput SetVisible true SavePreferences og og og e getSourc
9. output print CNAME output print output print fromSSRC output print output print aboutSSRC output print output print fraction output print output print packetsLost output print output printlin jitter return end of class RecordTas k 159 package org web3d vrtp rtp import import import import lt gt x public javax media javax media rtp java lang java net A class that represents necessary information to define an RTP session as address port and TIL author Francisco Afonso afonso cs nps navy mil version 1 0 class RtpMediaLocator extends MediaLocator Defines the value of TTL if not provided EI public static final int TTL_UNDEFINED 1 private String address private int port private int ttl TTL_UNDEFINED Constructor param locatorString Describes the session It should have the following format rtp address port ttl where lt P gt address multicast address of the rtp session P port port number P ttl optional gt time to liv public RtpMediaLocator String locatorString throws MalformedURLException super locatorString parseLocator locatorString this method parses the locator string to
10. 65 A INTRODUCTION hen bna tea t n tte Yn 65 B NETWORK MANAGEMENT OVERVIEW eene 65 RTP MIB DESCRIP TION irte Fh n Seow pitis 66 D COMPATIBILITY WITH JMF 66 E SUMMARY ce teaa minio Cn 67 MIEL EXPERIMEN TALARESULTS hiis toast ioe Git Ss eats Geen des cie d 69 A INTRODUCTIO Met rper bres redo 69 B TEST RESULTS vassals 69 C OBSERVED PROBLEMS eiit iate nn eto ascetics 70 D EXTENDING DIS JAV A VRML PDU HEADER 70 E SUMMARY 5 it Sam mU pocta aL TUARUM 71 CONCLUSIONS AND RECOMMENDATIONS eee 73 A RESBARCIDGONGCLUSIQONS t eds 73 RECOMMENDATIONS FOR FUTURE WORK 73 l Participants Information 73 pA Extensible Markup Language XML Recording 74 3 Recorded Data Analysis and 74 4 Session Description Protocol SDP Reception 74 5 RtpMonitor Activation from SDR see 74 6 JMF Extensibility for Other Media esses 75 7 Automated Network Monitoring of RTP Streams for VRTP 75 8 Design Patterns Course in Computer Science Curriculum 75
11. A Player or Processor generally provides two standard user interface components a visual component and a control panel component These components can be accessed by calling the getVisualComponent and getControlPanelComponent methods A DataSource represents a media stream which can have multiple channels of data called tracks For example a Quicktime Apple 99 file might contain both audio and video tracks Demultiplexing is the process of separating out the individual tracks of a complex stream Inside a Player or Processor several operations can take place For each operation there is a dedicated piece of software called a plug in There are five types of plug ins Demultiplexers extract individual tracks of media from a multiplexed media stream e Multiplexers join individual tracks into a single stream of data e Codecs perform media data encoding and decoding e Effect filters modify the track data in some way often creating some special effect They can be classified as post processing or pre processing effect filters depending on when they are applied in relation to the codec plug in Renderers delivers the media data in a track to presentation device For video the presentation device is typically the computer screen For audio the presentation device is typically an audio card 39 b DataSource Processor DataSource Figure 4 1 JMF High level API Connection Examples Figure 4 2 shows an e
12. TE Invalid PDUs Bad RTCP Packets Failed Transmission Duplicate PDUs Bad SR Packets Unknown Bad RR Packets Feedback Reports Passive Participants Previous hour Active Participants Username Fraction Lost Jitter Packets Lost The external viewer defined in the preferences will be called to present the output files These options can be executed during a monitoring session Below is an example of the Last five minutes file using MS Windows WordPad editor as an external viewer The format of the data is stored in the file statisticsHeader txt also shown below 86 statisticsLastFiveMinutes txt Notepad File Edi Search Help 18 25 27 9 8 1 5651647 6334 358 27 8 8 8 8 8 8 8 6 8 8 86 ellery 131 182 16 256 15651801658 963 5976 8 8 joel ja 128 223 214 27 1569838982 1564161640 6 6 8 8 brutzman accelerate 4285665786 1565101658 0 0390625 803 3626 ellery 131 182 16 256 1565181658 1564161646 6 61 8 niyake 3128 223 83 29 1568747521 15651801658 8 8 46 8 mmei 151 78 3 252 398571242 15651801658 8 8556875 17478 8 18 25 57 9 8 1 6893963 7723 428 33 8 8 8 80 8 8 8 6 8 8 8 ellery 131 182 16 256 1564161646 967 7296 8 8 8 joel ja 128 223 214 27 1569838982 1565181658 8 8 8 8 brutzman accelerate 4285665786 1564161646 6 69375 918 3057 ellery 131 182 16 256 15641081658 1564161646 8 8 1 8 miyake 128 223 83 29 1568747521 1565181658 8 8 42 8 mmei 141 78 3 242 398571242 1565181658 8 1815625 17614 8 18 26 27 9 8 1 8225
13. hourRange new hour ta from the last hour to the related date file String dateFi leName new String prefix Date dateRef txt concatenate dateFileName prefix LastHour txt if hourlast exists hourlast delete renames th hour renameTo hourRange h AF if it s statistics if dateRef dateRef e last hour file as the previous hour file hourlast ourRangeNow new date save the actual date in the LastDateRef file equals dateNow f dateNow saveDateR if there is not a new five minutes block just append the last report to the existing f dateRef last five minutes file concatenate prefix LastFiveMinutes txt prefix LastReport txt 149 LastHour txt prefix LastFiveMinutes txt Utility to concatenate two files param filel the first file filel lt filel file2 If filel does not exits this method will copy file2 to filel lt P gt param file2 the file to be appended to filel xk X X 255 public static void concatenate String filel String file2 try FileOutputStream output new FileOutputStream filel true FileInputStream input new FileInputStream file2 int mybyte while mybyte input read 1 output write mybyte output close input close catch FileNotFoundException e
14. offsetx 220 offsety ii 25 gLab ii new Label gField ii gLab ii setBounds 10 offsetx 130 ii 25 offsety 115 20 add gLab ii gText ii new TextField gText ii setBounds 125t offsetx 130 11 25 offsety 90 20 gText ii setEditable false add gText iil activeLabel new Label Active Participants activeLabel setBounds 50 340 140 20 activeLabel activeArea new TextArea 0 0 TextArea SCROLLBARS BOTH activeArea setBounds 10 360 175 180 activeArea setFont new Font Courier Font PLAIN 12 activeArea setEditable false activeArea passiveLabel new Label Passive Participants passiveLabel setBounds 230 340 140 20 passiveLabel passiveArea new TextArea 0 0 TextArea SCROLLBARS BOTH passiveArea setBounds 195 360 175 180 passiveArea setFont new Font Courier Font PLAIN 12 passiveArea setEditable false add passiveArea streamLabel new Label Stream streamLabel setBounds 470 120 50 25 add streamLabel streamChoice new Choice streamChoice setBounds 520 120 250 25 StreamChoice setEnabled false streamChoice addItemListener this 166 add streamChoice changeStream new Button Change changeStream setBounds 720 150 50 25 changeS
15. Dan C Boger Chair Department of Computer Science lv ABSTRACT The Real time Transport Protocol RTP supports the transmission of time based media such as audio and video over wide area networks WANs by adding synchronization and quality of service QoS feedback capabilities to the existing transport protocol RTP has been widely used in the Multicast Backbone MBone a virtual network that has become a shared worldwide medium for Internet multicast communications This work presents the design patterns architecture and implementation of an RTP monitor application using the Java Media Framework JMF a new Java Application Programming Interface API for multimedia support An RTP monitor is an application that receives packets from all participants in a multicast session in order to estimate the quality of service for distribution monitoring fault diagnosis and both short and long term statistics This new RTP monitor is available as a component of the Virtual Reality Transfer Protocol vrtp a protocol being developed to support large scale virtual environments LSVEs over the Internet Initial test results are satisfactory for audio and video streams as well as prototype RTP compliant Distributed Interactive Simulation DIS protocol streams Future work includes automated monitoring across WANs and standardizing structured data formats to comply with Management Information Base MIB requirements using Extensible Mar
16. Lean t input readUTF readInt C readUTF Exception System out println IO Exception getMessage end of class ModifyPreferences 154 package org web3d vrtp rtp impor impor impor impor impor impor lt P X KF CT gt avax media rtp avax media rtp event avax media rtp rtcp TER PE PET ava io ava sql ava util We ue C I A class used by RtpMonitorManager objects to write the statistics periodically to disk It is created as a separate thread that waits for a fixed period of time after writing data to disk This class writes data to the file called statisticsLastReport txt that contains only the last single report The FileCatalog class is actually responsible for transferring the data to the file statisticsLastFiveMinutes txt and other files author Francisco Afonso afonso cs nps navy mil version 1 0 public class RecordTask implements Runnable SessionManager mgr p mOouuu ods y 4 X X X X EN tpMonitorManager myMon hread thread oolean flgRun rintStream output tring dir tring prefix tring filename lendar timeNow i eCatalog cat nt recordParam Constructor It creates the session directory where the stats files will be written Also it
17. RTCP video port 4 RTCP video multicast address port 1 RTP audio audio port 1 RTP audio port 2 RTCP audio port 2 RTCP audio port 3 RTP video port 3 RTP video multicast address video port 4 RTCP video port 4 RTCP video Figure 3 3 RTP Addressing Configuration Examples 23 As all participants must send RTCP packets the rate must be controlled to avoid excessive RTCP traffic as the number of participants scales up This each participant must control his RTCP rate to guarantee that RTCP packets correspond to less than 5 of the RTP session Also it is recommended that at least 4 of the RTCP bandwidth would be dedicated to senders When the proportion of senders is greater than of the participants the sender gets its proportion from the full RTCP bandwidth It is further recommended that the interval between RTCP transmissions by each participant should always be greater than 5 seconds RFC1889 defines five types of RTCP packets e SR Sender Report for transmission and reception of statistics from participants that are active senders e RR Receiver Report for reception statistics from participants that are not active senders e SDES Source Description for each participant transfer information about himself e BYE to notify the end of participation e APP application specific functions Multiple RTCP packets need to be concatenated without any separator to form a com
18. Returns the RtpMediaLocator associated with the RTP session return the session media locator public RtpMediaLocator getMediaLocator return rtpml Returns the SessionManager object created by the monitor Qreturn the SessionManager RTPSessionMgr kf public SessionManager getSessionManager return mgr Returns the SessionAddress object associated with the RTP session return the SessionAddress A public SessionAddress getSessionAddress return sessaddr end of class RtpMonitorManager 185 package org web3d vrtp rtp F X FF Xo HF X RTPPlayerWindow java 1 7 98 03 28 Copyright 1996 1998 by Sun Microsystems Inc 901 San Antonio Road Palo Alto California 94303 U S A All rights reserved This software is the confidential and proprietary information of Sun Microsystems Inc Confidential Information You shall not disclose such Confidential Information and shall use it only in accordance with the terms of the license agreement you entered into with Sun import javax media Player import java awt import com sun media ui This class is used to create window for playing an audio video stream It is a subclass of PlayerWindow that added the capacity of modifying the window name Both classes were developed by SUN RTPPlayerWindow came with JMF1 1 sample code and PlayerWindow is in the file
19. System out println File not found 4 getMessage catch IOException e System out println IOException getMessage This method saves in a file a date in a string format It is used for save the date of the last report The file name is statisticsLastDateRef txt Qparam dater a string representing a date as DD MM YYYY public void saveDateRef String dater try DataOutputStream output new DataOutputStream new FileOutputStream prefix LastDateRef txt output writeUTF dater output close catch FileNotFoundException e System out println File not found getMessage catch IOException e System out println IOException 4 getMessage 150 This method retrives a date in a string format from the file statisticsLastDateRef txt return string representing a date as DD MM YYYY ah public String retrieveDateRef String result null try DatalnputStream input new DataInputStream new FileInputStream prefix LastDateRef txt result input readUTF input close catch FileNotFoundException e catch IOException e System out printin IOException getMessage return result end of class FileCatalog 151 package org import java import java web3d vrtp rtp awt awt event
20. mgr getGlobalReceptionStats c DI t new Time timeNow getTime getTime toString c t 7 t mgr getAllParticipants size ratory DM eee MT deis ed en ee rer 275 pm rS Ja p TES c T Rue itd a Ded QNNM D E ee s tpu prin 157 ou ou ou ou ou ou ou ou ou ou ou ou tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu cr ct Chet cb Eak chock ch cf prin prin prin prin prin prin prin prin prin prin prin prin CE r CV Fr CU CU fT CU CT er 1 stats getMalformedBye stats getLocalColls stats getRemoteColls stats getPacketsLooped stats getTransmitFailed n stats getUnknownTypes Records stream statistics private void records Receives Receptio tream stream nStats stats Participant part long SSRC String CNAME Vector aux lines starting with D2 treamStats mgr getReceiveStreams for int ii 0 ii aux size 11 stream ReceiveStream aux elementAt ii part stream getParticipant SSRC RtpUtil correctSSRC stream getSSRC if part null CNAME stream getParticipant getCNAME else
21. toString gText 12 setText new Integer stats getPacketsLooped toString gText 13 setText new Integer stats getTransmitFailed toString gText 14 setText new Integer stats getUnknownTypes toString stream ReceiveStream aux elementAt ii part stream getParticipant if part 11 display new String RtpUtil getUsernameOrCNAME part RtpUtil correctSSRC stream getSSRC else display new String unknown participant streamChoice add display streamTable put display if stream getSSRC dispStream stream new Long SSRCtoShow streamChoice select i if SSRCtoShow 0 if aux size gt 0 dispStream Receiv 1 Stream SSRCtoShow if dispStream null for int 31 0 13 lt 5 3 rText jjl setText SSRCtoShow 0 return stats dispStream getSourceReceptions rText 0 setText new Integer stats ge rText 1 setText new Integer stats ge rText 2 setText new Integer stats get rText 3 setText new Integer stats get rText 4 setText new Integer stats ge 172 stream getSSRC 1 ct U U td aux elementAt 0 dispStream getSSRC ts DUlost toString DUProcessed toString DUMisOrd toString DUInvalid toString DUDuplicate toString RtpUtil c
22. APPENDIX A PREPARING UML DIAGRAMS USING RATIONAL ROSE 77 APPENDIX B RTPMONITOR USER MANUAL 79 APPENDIX C RTPMONITOR 91 APPENDIX D RTPMONITOR SOURCE CODE mm 137 APPENDIX E COMPARISON RTP MIB VERSUS JMF STATISTICS 191 APPENDIX RTPHEADER 4 440 nnne 192 APPENDIX RTPHEADER SOURCE CODE 207 EIST OP REFERENCES 213 INITIAL DISTRIBUTION LIST itii fih tht eer etri eee tet tede eis 217 ACKNOWLEDGEMENTS I would like to thank my wife Helena for the continuous support and patience regarding my academic work at NPS To Professor Brutzman I offer my thanks for the friendship and enthusiasm I have experienced during this time xi Xil I INTRODUCTION A BACKGROUND The Multicast Backbone MBone is a virtual network that has been in operation since 1992 It was initially used to multicast audio and video from meetings of the Internet Engineering Task Force but nowadays it has become a shared worldwide medium with many diverse channels for Internet multicast communications Macedonia et al 94 The Real time Transport Protocol RTP was developed to support time based media such as audio and video over multicast capable networks Schulzrinne et al 99 RTP is the basic pack
23. ActiveRecvStreamEvent generated when the stream data packets have started arriving after a previous stop InactiveSendStreamEvent generated when the stream data packets have stopped arriving PayloadChangeEvent generated when a remote sender has changed the payload type of a data stream TimeOutEvent generated when a remote sender has not sent packets for a while and can be considered timed out A time out has the same effect as if the participant has sent the RTCP BYE packet RecvStreamMappedEvent generated when a recently created stream has been associated with a participant after the first RTCP packet has been received AppEvent generated when an RTCP APP packet has been received The RTPRemoteListener interface detects events related to RTCP control messages received from remote participants This interface can be used for monitoring applications that do not need to receive each stream but only RTCP reports Three types of events can be posted 6 RecvReceiverReportEvent generated when a new RTCP RR report has been received RecvSenderReportEvent generated when a new RTCP SR report has been received RemoteCollisionEvent generate when two remote participants are using the same SSRC simultaneously Upon detecting the collision both remote participants should start sending data with new SSRCs RTP Media Locator and RTP Session Address RTPMediaLocator is a class that stores inf
24. Vector getRecv Streams Vector 1 mantains manages gus lt lt gt gt Interf ace gt gt RTPStream GlobalTransmissionStats P Interf ace gt gt Interf ace gt gt RTPRecvStream RTPSendStream getSourceTransmissionStats getSourceReceptionStats 1 1 1 1 Interf ace gt gt Interf ace gt gt RTPTransmissionStats RTPReceptionStats Figure 4 7 RTP Statistics Class Diagram 53 D SUMMARY The Java Media Framework architecture is intended to support multimedia in a variety of applications It is based in a high level API containing generic classes to capture and present media and a low level API to allow customization and extension The RTP API supports RTP transmission and reception as well as retrieval of RTP statistics Future work on JMF can include the transmission of time based media other than audio and video such as the Distributed Interactive Simulation DIS protocol and other behavior based streams 54 V DESIGN AND IMPLEMENTATION OF THE RTPMONITOR APPLICATION A INTRODUCTION This chapter covers the functionality and class design of the program developed as the main goal of this thesis called rtpMonitor rtpMonitor is a Java application that presents and records RTP statistics about a single RTP session It can also present the media being received eith
25. receive only the RTCP packets and not the corresponding RTP data streams to evaluate the performance of their networks for multicast distribution These mechanisms also support protective and corrective mechanisms such as congestion avoidance and congestion control The interarrival jitter field provides a short term measure of network congestion The packet loss metric tracks persistent congestion while the jitter measure tracks 33 transient congestion The jitter measure may indicate congestion condition forming before it leads to packet loss H RTP PROFILES AND PAYLOAD FORMAT SPECIFICATIONS RTP is intended to be tailored through modifications and or additions to the headers as needed Multiple profiles have been defined each with different characteristics Therefore for a given application a complete specification will require one or more companion documents as follows 1 Profile Specification Documents A Profile Specification Document defines a set of payload type codes and their mapping to payload types A profile may also define extensions or modifications to RTP that are specific for that kind of applications The only profile document issued as of this writing is RFC 1890 RTP Profile for Audio and Video Conferences with Minimal Control 2 Payload Format Specification Documents A Payload Format Specification Document defines how a particular payload such an audio or video encoding is to be carried in R
26. 22030 Jaton nter cese E Chief Scientist Advanced Network amp Services Inc 200 Business Park Drive Armonk NY 10504 USA Bob Barton 2 2 bees ere trie ie Soe dates Fraunhofer CRCG 321 South Main St Providence RI 02903 Michael D MYjak 42 ae er eesiada ont aves TA pastes SS XX THER UERE Vice President R amp D The Virtual Workshop Inc P O Box 98 Titusville Florida 32781 tede meii ius Sprint ATL 1 Adrian Court Burlingame CA 94010 CrOWCEORt cede d Department of Computer Science University College London Gower Street London WCIE 6BT United Kingdom Kevin C Almetroth 5e neve A Computer Science Department University of California Santa Barbara CA 93106 T tae ad titer eun Java Media Framework Techical Lead Sun Microsystems 901 San Antonio Road Palo Alto CA 94303 218 18 19 20 21 22 23 Intel Corporation 2111 N E 25th Avenue Hillsboro Oregon 97124 Lawrence A OE E Computer Science Division EECS University of California Berkeley Berkeley CA 94720 1776
27. CNAME new String Unknown Participant stats stream getSourceReceptionStats output print D2 output print CNAME output print output print SSRC output print output print stats getPDUlost output print output print stats getPDUProcessed output print output print stats getPDUMisOrd output print output print stats getPDUInvalid output print output println stats getPDUDuplicate 158 Records feedback statistics lines starting with D3 private void recordFeedbacks Participant part Vector reports Report rep Feedback feedbk String CNAME long fromSSRC double fraction long packetsLost Vector aux feedbacks aboutSSRC jitter mgr getAllParticipants for int ii 0 ii aux size 11 part Participant aux elementAt ii CNAME part getCNAME reports part getReports for int 33 0 11 lt reports size rep Report reports elementAt jj fromSSRC RtpUtil correctSSRC rep getSSRC feedbacks rep getFeedbackReports for int kk 0 kk lt feedbacks size kk feedbk Feedback feedbacks elementAt kk aboutSSRC RtpUtil correctSSRC feedbk getSSRC fraction feedbk getFractionLost 256 0 packetsLost feedbk getNumLost jitter feedbk getJitter output print D3
28. Instituto de Pesquisas da Marinha eese Rua Ipiru 2 Ilha do Governador Rio de Janeiro RJ Brazil Diretoria de Sistemas de Armas da Marinha Rua Primeiro de Margo 118 Rio de Janeiro RJ Brazil CEP 20010 Centro de Instru o Almirante Wandenkolk Ilha das Enxadas Rio de Janeiro RJ Brazil CEP 20000 LCDR Francisco Carlos Afonso Rua Marques de Valenca 40 201 Tijuca Rio de Janeiro RJ Brazil CEP 20010 2 9
29. RcvrSSRC Unsigned32 the SSRC of the RcvrSSRC long receiver Type issue RevrCNAME DisplayString the canonical RcvrCNAME String name of the receiver RcvrAddr Taddress the unicast transport Not implemented It can be added address of the receiver 197 RcvrRTT Gauge32 the round trip time Not provided by JMF This value can only be calculated by measurement taken by the source of the RTP senders after receiving RTP feedback about stream their streams JMF does not provide this statistic This capability was requested was requested in the jmf interest mailing list RevrLostPackets Counter64 a count of RcvrLostPackets long RTP packets lost as observed by this receiver RcvrJitter Gauge32 an estimate of delay RevrJitter long Type issue variation as observed by this receiver RevrTool DisplayString the name of the Not implemented It can be read from JMF application program source of the stream RTPSourceDescription object RRs Counter32 a count of the number of Not implemented Not part of native JMF statistics It can be RTCP Receiver Reports that have been sent derived in an JMF application by from this receiver since RcvrStartTime monitoring RecvSenderReportEvents RcvrRRTime TimeStamp the value of Not provided by JMF JMF does not provide the time a feedback SysUpTime at the last RTCP Receiver Report is received or sent This capability was was received or sent in
30. The RtpHeader class was briefly tested during the period of this thesis Client software automatically discriminates among DIS PDUs with and without RTP headers This is an excellent result Further testing is required as a future work E SUMMARY The rtpMonitor application has successfully been tested with different versions of the Java Development Kit JDK and Java Media Framework JMF The program proved to be robust in several long term monitoring sessions Despite most JMF problems have been solved in version 2 0 Early Access additional fix should be done A new header for the Protocol Data Units PDU of the DIS Java VRML application was developed and initial test produced excellent results 71 THIS PAGE LEFT INTENTIONALLY BLANK 72 VIII CONCLUSIONS AND RECOMMENDATIONS A RESEARCH CONCLUSIONS The RTP monitor application has been successfully implemented using Java Media Framework JMF The monitor can be applied to help detecting problems in RTP based multicast session by adding statistics recording capabilities not available in the existing individual conference applications The presentation of RTP statistics and feedback reports in a single screen is also a good feature for on line monitoring The RtpMonitor class package can be used by future RTP applications as a simple means to record statistics with no direct access needed to JMF resources This is an important new capability since core Java classes do not prov
31. an RTP header 4 8 9 16 31 V PX CC M PT sequence number timestamp synchronization source SSRC identifier contributing source CSRC identifiers Figure 3 1 RTP Header Contents Schulzrinne et al 99 The following information is part of the header Version V 2 bits Identifies the version of RTP The current version defined in RFC1889 is two 2 Padding P 1 bit If the padding bit is set the packet contains one or more additional padding bytes The last byte contains the number of padding bytes including itself The RTP header has no packet length field 19 e Extension X 1 bit If this bit is set the header will be followed by a header extension CSRC count CC 4 bits Contains the number of contributing source identifiers in the header e Marker M 1 bit Can be used by a profile e Payload type PT 7 bits Identifies the type of data payload carried by the packet The payload types for standard audio and video encodings are defined in RFC1890 Schulzrinne 99 e Sequence number 16 bits It is incremented each time a packet is sent The initial value is randomly generated e Timestamp 32 bits This field reflects the sampling instant of the first byte of data The clock frequency depends of the data type For example if audio data is being sampled at 8KHz and each audio packet has 20 ms of samples 160 sample values the timestamp
32. and Header txt to the new directory Then run rtpMonitor from this directory Example copy bookmarks txt c MMydir copy Header txt c MMydir cd Mydir java org web3d vrtp rtp RtpMonitor 12 Reinstallation recommendations In order to continue using the previous bookmarks and preferences the files bookmark txt and preferences txt in the directory vrtp rtpMonitor should be saved and restored after the new installation To reinstall the program it is recommended the deletion of the following directories vrtp javadoc rtpMonitor vrtp org web3d vrtp rtp vrtp rtpMonitor 89 THIS PAGE LEFT INTENTIONALLY BLANK 90 APPENDIX C RTPMONITOR JAVADOC The rtpMonitor Javadoc is available at http www web3D org WorkingGroups vrtp javadoc rtpMonitor index html 91 APPENDIX D RTPMONITOR SOURCE CODE package org web3d vrtp rtp import java awt import java awt event import java util Dialog to display information about the program e g version date lt P gt author Francisco Afonso afonso cs nps navy mil version 1 0 X public class About extends Dialog Constructor lt P gt param parent the parent frame 7 public About Frame parent super parent About true setSize 270 200 setLayout null setBackground Color lightGray addWindowListener new CloseWindow Label versionLabel new Label rtpMonitor vers
33. button Delete Bookmark Dis Java Vrml audio DIS Java VRML DIS PDUs Capitol GMU video Capitol GMU audio Nasa TV from video Nasa TV from HG audio Places all over world video 4 Preferences Before starting to monitor a session the user should set up the program preferences The menu Preferences allows the verification and modification of the program preferences Selecting Preferences gt Modify the following window will be presented Modify Preferences C Program Files PFE Programmers File Edito 83 The options are Send RTCP packets checkbox defines if the monitor will participate in the session sending RTCP packets e Play incoming media checkbox defines if the monitor will play the received streams audio or video For video a new playing window will be created for each active participant stream For audio only one playing window will be created e Record statistics checkbox defines if the monitor will record the session statistics in files Record Interval textbox the user can enter the interval between recorded data in seconds default 30 sec e Presentation Interval textbox the user can enter the interval between data updates on screen in seconds default 5 sec e Monitoring Period choicebox allows the user to specify the duration of the monitoring session After the time is over the program will exit automatically The maximum allowed duration is
34. can be analyzed to provide information such as receiver lists over time route histories and changes as well as the location duration and frequency of packet loss Makofske et al 99 MHealth was written in Java but needs mtrace for its operation Version 1 0 can be downloaded at http steamboat cs ucsb edu mhealth download v1 0 12 Session Address 224 2 253 119 42418 Local Time Thu Aug 20 10 49 30 PDT 1998 Status Mtracing receiver lyceum Ibl gov 131 243 112 909 kachinajetcafe org 1 237 192 12 19 253 29 236 0 E 6 0 236 engr gw ucsb edu 204 70 2 173 207 12 55 99 2 203 5 266 0 236 blackcomb 198 32 136 66 204 70 158 77 Mtrace COMPLETE 1 261 0 236 4 0 0 34 0 262 163 236 132 42 110 243 205 207 237 48 0 262 773 Help Quit Figure 2 5 MHealth display showing participants in multicast tree Robinson et al 96 D VRTP The Virtual Reality Transfer Protocol vrtp is a protocol being developed to provide client server multicast streaming and network monitoring capabilities in support of internetworked 3D graphics and large scale virtual environments LSVEs Brutzman 99 vrtp is designed to support interlinked VRML worlds in the same manner as http was designed to support interlinked HTML pages The intent is to develop a free library 13 to provide any machine with client server peer to peer and network monitoring capabilities to navigate and join large in
35. each representing one description information as CNAME name e mail location tool etc 43 The method getSourceDescription of RTPParticipant returns a vector with the RTCPSourceDescription objects related to the participant 4 RTCP Report Passive participants send RTCP RR packets as a feedback about the reception of incoming streams Active participants send RTCP SR packets that give information about the stream being sent and also include feedback about the reception of incoming streams So a SR packet includes the RR packet information A RTCP SR or RR packet is originated from each SSRC identifier A participant may have more than one SSRC identifier if it is source of more than one stream in the same session Each SSRC is related to one stream In spite of it each participant has only one CNAME RTCP SDES packets allow the correlation between SSRC and CNAME In JMF there is an interface called RTCPReport to represent both RTCP SR and RTCP RR packets RTCPReport has two sub interfaces RTCPSenderReport and RTCPReceiverReport RTCPReceiverReport is a marker interface All of its functionality is contained in RTCPReport RTCPSenderReport extends RTPCReport to provide methods for retrieve sender report information The method getReports of RTCPParticipant returns a vector containing the last SR or RR reports sent by the participant This method will usually return only one report SR if the participant is active and it sends only one
36. information about the session reachability 3 Rtpmon Rtpmon is a third party RTP monitor written in C by the Plateau Multimedia Research Group at Berkeley Version 1 0 was the last release in 1996 It works only on Unix systems Both source code and binaries are available It is possible to integrate rtpmon with vic and or vat by modifying the files vic tcl and or vat tcl This will add a monitor button to vic and vat that when pressed will launch rtpmon Agarwal 97 Rtpmon provides a number of useful capabilities for sorting filtering and displaying the statistics generated in an RTP session David 96 Figure 2 3 shows an example of the rtpmon Graphical User Interface GUI It displays RTCP statistics in a table with senders listed along the top and listeners along the left Each entry in the table corresponds to the data obtained about a single sender receiver pair The program listens to RTCP messages on a multicast address specified at startup time there is no provision for displaying data from multiple sessions Information about each participant can be obtained by clicking the participant s name in the table display doing so brings up a window with the session description items provided in the member s RTCP reports The information window also contains a button which spawns mtrace for detailed single sender receiver multicast routing data Rtpmon can also display a brief history of the statistics from each sender receiver pair Cli
37. internet drafts draft ietf avt rtp new 04 txt Schulzrinne RTP Profile for Audio and Video Conferences with Minimal Control Internet Draft draft ietf avt profile new 06 txt RFC 1890 Internet Engineering Task Force 25 June 1999 Available at http www ietf org internet drafts draft ietf avt profile new 06 txt Stallings W Data and Computer Communications Fifth Edition pp 685 697 Prendice Hall 1997 Sun Microsystems Inc Java Media Framework API http www javasoft com products java media jmf index html July 1999 Sun Microsystems Inc Java Media Framework API Programmer s Guide v 0 7 21 May 1999 Available at http www javasoft com products java media jmf 2 0 jmf20 07 guide pdf Sun Microsystems Inc Java Media Framework Early Access Specification v 0 7 Javadoc May 1999 Available at http www javasoft com products java media jmf 2 0 jmf20 07 apidocs index html Sun Microsystems Inc Java Native Interface http java sun com products jdk 1 2 docs guide jni index html August 1999 UCL Networked Multimedia Research Group Videoconferencing Tool 214 http www mice cs ucl ac uk multimedia software vic June 1999 UCL Networked Multimedia Research Group User Guide for VIC v2 8 Version 1 DRAFT 29 September 1998 Available at http www mice cs ucl ac uk multimedia software UCL Networked Multimedia Research Group Robust Audio Tool http www mice cs ucl ac
38. must be registered with the class PlugInManager 41 New Players Processors DataSources and DataSinks must be registered with the class PackageManager D RTP SESSION MANAGER API The RTP Session Manager API is the part of JMF API that deals with RTP RTCP transmission and reception It is contained in two packages javax media rtp and javax media rtp session The RTPSessionManager interface is responsible for entering mandatory conventions for creating maintaining and closing an RTP session It detects incoming RTP streams maintains a list of RTP participants and transmits outgoing streams It also keeps track of global statistics about the session Since javax media rtp session RTPSessionManager is an interface an implementation is provided by Sun in the file jmf jar The class name is RTPSessionMgr There is currently no source code available for this package The following line creates an RTPSessionManager RTPSessionManager mgr new com sun media RTP RTPSessionMgr 1 RTP Streams RTPStream is an interface that represents a series of data packets originated from a single host There are two sub interfaces of RTPStream RTPRecvStream and RTPSendStream The first represents a stream that is being received from a remote participant RTPSessionManager creates RTPRecvStream objects automatically when new receiving streams are detected The second represents a stream being sent by a local 42 participant RTPSessionManager
39. n h RtpMonitorCommandLine rtpLocator lt options gt ln example rtp 224 2 125 50 50328 127 ntlin part monitor sends packets ntlin play monitor play streams tin ecord monitor records statistics Ln nnn nnn defines the recording interval in seconds default 30s Ln ppp ppp defines the monitoring duration in hours default 168 hs in elp displays command line format and aborts parses the command line arguments to extract the options locator args 0 int ii 1 while ii nArgs if args ii indexOf part true willpart 178 else if args ii indexOf play 0 willplay true else if args ii indexOf record 0 willrecord true else if args ii 0 amp amp ii lt nArgs 1 interval Double parseDouble args iit l else if args ii indexOf e 0 amp amp ii nArgs 1 endsInHours Integer parseInt args ii 1 1144 ndDate new Date new Date getTime endsInHours 3600000L displays the selected options on the console System out println locator locator System out printin play willplay System out printin part willpart System out println record willrecord System out println recording interval i
40. new MenuItem View viewPref addActionListener this modifyPref new MenuItem Modify modifyPref addActionListener this preferences add viewPref preferences addSeparator preferences add modifyPref bookmarkMenu new Menu Bookmarks addBm new MenuItem Add addBm setEnabled false deleteBm new MenuItem Delete selectBm new MenuItem Select selectBm addActionListener this deleteBm addActionListener this addBm addActionListener this bookmarkMenu add selectBm bookmarkMenu addSeparator bookmarkMenu add addBm bookmarkMenu addSeparator bookmarkMenu add deleteBm filesMenu new Menu File last5Item new MenuItem Last five minutes last5Item addActionListener this previousSItem new MenuItem Previous five minutes previousbItem addActionListener this 164 lastHourItem new Menultem Last hour lastHourItem addActionListener this previousHourlItem new MenuItem Previous hour previousHourItem addActionListener this headerItem new MenuItem Header headerItem addActionListener this xitItem new Menultem Exit exitItem addActionListener this filesMenu add last5Item filesMenu add previousb5Item FilesMenu add lastHourItem filesMenu add previousHourItem FilesMenu addSeparator filesMenu add headerItem Fi
41. newPlayer Manager createPlayer dsource if a player was created generates a player window if newPlayer null playerWindow new RtpPlayerWindow newPlayer cname windowlist put stream playerWindow catch Exception e System err printlin NewRecvStreamEvent exception 4 getMessage return if the sender of a stream was identified if event instanceof StreamMappedEvent gets the ReceiveStream object ReceiveStream stream StreamMappedEvent event getReceiveStream gets the Participant associated with the stream Participant part stream getParticipant retrieves the correct player window from the hash table if stream null playerWindow RtpPlayerWindow windowlist get stream change the title of the player window to include the name of the sender if playerWindow null amp amp par playerWindow Name part getCNAM null E Ct 184 Closes a monitor session stops recording and closes player windows y public void close if flgRecord recTask exit if flgPlay Enumeration windows windowlist elements while windows hasMoreElements RtpPlayerWindow currwindow RtpPlayerWindow windows nextElement if currwindow null currwindow killThePlayer mgr closeSession null mgr null
42. of RTP data packets that failed the RTP header validation check Not provided by MIB BadRTCPPackets int the total number Desirable of RTCP packets that failed the RTCP header validation check Not provided by MIB MalformedSR int the total number of Desirable invalid sender reports due to length inconsistency Not provided by MIB MalformedRR int the total number of Desirable invalid receiver reports due to length inconsistency Not provided by MIB MalformedSDES int the total number Desirable of invalid SDES packets due to length 194 2 imemsisteny 0000000 J Not provided by MIB MalformedBYE int the total number Desirable of invalid BYE packets due to length inconsistency LocalCollisions int the total number Desirable of local collisions SSRC collisions RemoteCollisions int the total number Desirable of remote collisions SSRC collisions Not provided by MIB PacketsLooped int the total number of Desirable packets looped Not provided by MIB FailedTransmission int the number of Desirable packets that failed to get transmitted Not provided by MIB UnknownRTCPType int the number Desirable of individual RTCP packets types that were not implemented or not recognized 195 SenderTable RTP MIB JMF based RTP Monitor Application SenderSSRC Unsigned32 the sender SenderSSRC long Slight type mismatch but workable synch
43. output try output new PrintStream new FileOutputStream bookmarks txt false for int 11 0 ii lt sessionAddressVec size 11 output print sessionNamesList getItem ii output przrnt Ww Moy output println String sessionAddressVec elementAt ii output close catch FileNotFoundException e System out println Saving bookmarks 4 getMessage catch IOException System err println Exception writing bookmark getMessage end of class DeleteBookmark 144 package org web3d vrtp rtp import javax media rtp import javax media rtp event import javax media rtp rtcp import java awt import java util A class used by RtpMonitor objects to periodically launch their showStats methods screen updates p author Francisco Afonso afonso cs nps navy mil version 1 0 public class DisplayTask implements Runnable RtpMonitor myMon SessionManager mymgr Thread threag int intervalParam Constructor It creates a new thread of execution and calls the method run param mon the RtpMonitor object that will be called back for screen updates param interval the interval between screen data updates in seconds public DisplayTask RtpMonitor mon double interval myMon mon intervalParam int interval 1000 thread new Thread this DisplayTask thre
44. public UnsignedInt getSSRC return UnsignedInt SSRC clone 209 Sets the packet sequence number param pSequenceNumber the sequence number as an unsigned short 16 bits X public void setSequenceNumber UnsignedShort pSequenceNumber sequenceNumber pSequenceNumber Sets the packet timestamp param pTimestamp the timestamp as an unsigned int 32 bits xy public void setTimestamp UnsignedInt pTimestamp timestamp pTimestamp Sets the Syncronization Source Identifier param pSSRC the SSRC as a unsigned int 32 bits ky public void setSSRC UnsignedInt pSSRC SSRC pSSRC Increments the sequence number The RtpHeader class mantains a static variable with the next sequence number to be assigned to a packet This function increments this variable If the sequence number will exceed the 32 bits boundaries it is set to zero 47 private void incrementSequenceNumber if after the increment the sequence number gets longer than 16 bits than it should be set to zero nextSequenceNumber if nextSequenceNumber gt UnsignedShort MAX SHORT VALUI nextSequenceNumber 0 Gl return 210 Prepares the header for sending Assigns the sequencial number from a static variable param pdu the DIS pdu that will public void prepareToSend Pro
45. type number was set to 111 It belongs to the dynamic assignment range 96 127 Numbers in this range do not need to be registered p See a href http www ietf org internet drafts draft new 06 txt http www ietf org internet drafts draft ietf avt prof Session 3 E public static final int RTP_PAYLOAD_TYPE_FOR_DIS 111 208 ietf avt profile ile new 06 txt a Contains the size of the header in bytes 12 77 public static final int sizeOf 12 the packet sequence number private UnsignedShort sequenceNumber the packet timestamp private UnsignedInt timestamp the packet Sincronization Source Identifier SSRC private UnsignedInt SSRC Constructor An empty header is created public RtpHeader sequenceNumber new UnsignedShort timestamp new UnsignedInt SSRC new UnsignedInt return Returns the packet sequence number return the sequence number as an unsigned short 16 bits public UnsignedShort getSequenceNumber return UnsignedShort sequenceNumber clone Returns the packet timestamp return the timestamp as an unsigned int 32 bits xy public UnsignedInt getTimestamp return UnsignedInt timestamp clone Returns the packet Syncronization Source Identifier return the SSRC as an unsigned int 32 bits y
46. 0 25 deleteButton addActionListener this deleteButton cancelButton new Button Cancel cancelButton setBounds 130 260 60 25 cancelButton addActionListener this add cancelButton 142 Takes action when buttons are selected public void actionPerformed ActionEvent e if e getSource deleteButton int index sessionNamesList getSelectedIndex if index gt 0 sessionNamesList remove index sessionAddressVec remove index saveBookmarks if e getSource cancelButton setVisible false Loads the session bookmarks from file bookmarks txt Nf private void loadBookmarks sessionAddressVec new Vector try BufferedReader input new BufferedReader new FileReader bookmarks txt String line while line input readLine null int pos line lastIndexOf rtp if pos 1 sessionAddressVec addElement line substring pos trim sessionNamesList add line substring 0 pos trim input close catch FileNotFoundException e System out println Delete Bookmarks getMessage catch IOException System err println Exception reading bookmark getMessage 143 Saves the session bookmarks to file bookmarks txt private void saveBookmarks PrintStream
47. 05 if the user has selected for no participation in the session sets the fraction above to zero no RTCP packets if flgPart rtcpFraction 0 0 initiates the SessionManager object mgr initSession localaddr userdesclist rtcpFraction 0 25 int ttl rtpml getTTL starts the SessionManager object mgr startSession sessaddr ttl null if the user has selected for recording statistics creates a RecordTask objet to generate the reports periodically if flgRecord recTask new RecordTask this recordInterval Method of classes that implement the ReceiveStreamListener interface public void update ReceiveStreamEvent event Player newPlayer null RtpPlayerWindow playerWindow null String cname null SessionManager source SessionManager event getSource if a new stream is received if event instanceof NewReceiveStreamEvent gets the ReceiveStream object try ReceiveStream stream NewReceiveStreamEvent event getReceiveStream 183 gets the Participant object associated with the stream Participant part stream getParticipant gets the participant canonical name if part null cname part getCNAME gets the stream DataSource associated with the stream DataSource dsource stream getDataSource creates a player to play the DataSource
48. 128 Fills the header contents with data from a DataInputStream param inputStream the stream which contains the header public void deSerialize DataInputStream inputStream UnsignedByte firstByte new UnsignedByte 0 UnsignedByte secondByte new UnsignedByte 0 deserializes firstByte deSerialize inputStream secondByte deSerialize inputStream sequenceNumber deSerialize inputStream timestamp deSerialize inputStream SSRC deSerialize inputStream return Makes deep copies of all the instance variables public Object clone RtpHeader newHeader RtpHeader super clone newHeader setSequenceNumber this getSequenceNumber newHeader setTimestamp this getTimestamp newHeader setSSRC this getSSRC return newHeader Prints internal values for debugging 7 public void printValues int indentLevel PrintStream printStream StringBuffer buf ProtocolDataUnit getPaddingOfLength indentLevel printStream printin buf sequenceNumber 4 sequenceNumber intValue printStream println buf timestamp timestamp longValue printStream println buf SSRC SSRC longValue return end of class RtpHeader 212 LIST OF REFERENCES Advanced Neworks and Services Internet2 Building the Next Generation Internet http www advanced org surv
49. 1889 In order to create a RTPSessionAddress object for representing a session address two InetAddress objects are required as arguments one for RTP and other for RTCP The InetAddress class is part of the java net package and encapsulates an IP address The static method getByName can create a InetAddress object given a string with the IP address Figure 4 4 contains a sequence diagram that describes the creation of a RTPSessionAddress object 48 user program RTPMedia InetAdress RTPSession Locator Address create String mediaLocator address getSessionAddress port getSessionPort destaddr getByName address sessaddr create destaddr port destaddr port 1 Figure 4 4 RTPSessionAddress Creation UML Sequence Diagram 7 RTP Session Manager After creating an empty RTPSessionManager object as described in item C a RTPSessionManager must be initialized by calling the method initSession The required parameters are e The local IP address as a RTPSessionAddress object This object can be created by calling the RTPSessionAddress constructor with no arguments e An array of RTPSourceDescription objects containing information about the local participant e The fraction of the bandwidth to be allocated to RTCP RFC1889 recommends 5 of the RTP bandwidth 49 e The fraction of
50. 868 9184 497 38 866666666686 ellery 131 182 16 256 1564161646 1869 8688 8 6 joel ja 128 223 214 27 1569838982 15651801658 8 8 8 8 brutzman accelerate 4285665786 1565101648 8 0556875 1823 2953 ellery 131 182 16 256 1564161646 1564161646 8 8 1 8 miyake 128 223 83 29 1568747521 15651801658 8 8 44 8 mnei 141 78 3 242 398571242 15651816458 6 68984375 17738 8 18 26 57 9 8 1 9499537 10587 556 6660660666666 ellery 131 182 16 256 15645181658 1214 16031 8 8 8 joel ja 128 223 214 27 1569838982 15651801658 8 8 8 8 brutzman accelerate 4285665786 1565101658 8 015625 1053 3332 ellery 131 182 16 256 15651816580 1564161646 6 61 8 miyake 128 223 83 29 1568747521 156518016458 8 8 44 8 mmei 141 78 3 242 398571242 15651801658 8 8089845375 17866 8 18 27 27 9 8 1 10912865 12114 627 47 6660686666666 6 ellery 131 182 16 256 1564161646 1238 11488 6 6 8 joel ja 128 223 214 27 1569838982 1564161646 8 8 8 statisticsHeader txt Notepad i O xi File Edit Search Help H2 CNAME SSRC LostPDU ProcessedPDU HisorderedPDU InvalidPDU DuplicatePDU H3 CNAME FromSSRC AboutSSRC FractionLost PacketsLost Jitter Each line of data is preceded with a header indicator D1 D2 or D3 which indicates the line of the statisticsHeader file that contains the description of the data being stored H1 H2 or H3 87 9 Using the monitor without GUI The program can be executed without the GUI no statistics are presented by passing the session address and opti
51. Appendix A 4 Media Presentation rtpMonitor can present the incoming video stream on the computer screen or the incoming audio streams on the computer speakers This option is selected in the Preferences menu In case of video each stream is presented in a separate window In case of audio a toolbar window is opened to allow audio controls such as the mute function The launched applications are part of the JMF API 5 Command Line Operation If the program is called with any argument in the command line the GUI will not be launched In this case the session address and preferences must be passed by the command line 57 The following command line is an example of invocation of the rtpMonitor to record statistical data and present RTP session streams during a period of 24 hours java org web3d vrtp rtp RtpMonitor rtp 224 120 67 46 64542 12 play record 24 Using the command line version of rtpMonitor no statistics are sent to the console A monitoring session be stopped by pressing Crtl C C RTPMONITOR CLASS DESIGN The rtpMonitor class design goal was to create a set of basic classes that could perform the RTP monitoring tasks with minimal access from user applications to the Java Media Framework API Figure 5 2 contains a data flow diagram showing the exchange of data statistics settings and commands between classes in rtpMonitor Each bubble in the diagram will be discussed in the remainder of this
52. CL The latest version is 4 0 3 UCL 99 Figure 2 2 shows an example of RTP statistics available in RAT Each set of statistics is related to one receiving audio stream Participant Capitol Connection OF xi Reception Figure 2 2 RTP Statistics in RAT DEDICATED MONITORS 1 Mtrace Mtrace allows the user trace a route from a receiver to a source working backwards using a particular multicast address It runs only on Unix systems If either the receiver or the source is not participating in a multicast on the specified address then mtrace may not work Vic and vat can automatically launch the mtrace utility Mtrace is included in the mrouted distribution and can be downloaded at the following site http www cs unc edu wangx MBONE mbonetoolarchive html mtrace 2 Session Directory SDR Monitor SDR Monitor short for SDR Global Session Monitoring Effort is an effort to track manage and present information about the availability of world wide multicast sessions using the SDR tool Sarac 99 SDR is a session directory tool designed to allow the advertisement and joining of multicast conferences on the MBone UCL 99 The basic idea of the SDR Monitor is that the SDR application can periodically send an an email to the project control containing all the session announcements that are being received at the user site All data collected is made available in world wide web page using a tabulated form that conveys
53. DRESS ES PERFORMING ORGANIZATION Naval Postgraduate School BEFORENOMEER Monterey CA 93943 5000 SPONSORING MONITORING AGENCY NAME S AND ADDRESS ES SPONSORING MONITORING AGENCY REPORT NUMBER SUPPLEMENTARY NOTES The views expressed in this thesis are those of the author and do not reflect the official policy or position of the Department of Defense or the U S Government 12a DISTRIBUTION AVAILABILITY STATEMENT 12b DISTRIBUTION CODE Approved for public release distribution is unlimited 13 ABSTRACT The Real time Transport Protocol RTP supports the transmission of time based media such as audio and video over wide area networks WANs by adding synchronization and quality of service QoS feedback capabilities to the existing transport protocol RTP has been widely used in the Multicast Backbone MBone a virtual network that has become a shared worldwide medium for Internet multicast communications This work presents the design patterns architecture and implementation of an RTP monitor application using the Java Media Framework JMF a new Java Application Programming Interface API for multimedia support An RTP monitor is an application that receives packets from all participants in a multicast session in order to estimate the quality of service for distribution monitoring fault diagnosis and both short and long term statistics This new RTP monitor is available as a component of the Virtual Reality Transfer Proto
54. ESCRIPTION RTP agents running this MIB can be either RTP hosts end systems or RTP Monitors The objective is to collect statistical data about RTP sessions and its streams for diagnostics and management purposes Each agent maintains a MIB that can be queried by a Manager Only the last updated statistic is stored in the MIB RTP MIB has three tables rtpSessionTable contains objects that describe active sessions at the host intermediate system or monitor There is an entry in this table for each RTP session on which packets are being sent received and or monitored rtpSenderTable contains information about senders of the RTP session RTP sender hosts must have an entry in this table for each stream being sent but RTP receiving hosts do not have to maintain this table RTP Monitors must create an entry for each observed stream rtpRevrTable contains information about receivers of the RTP session RTP receivers must create an entry in this table for each received stream RTP senders do not have to maintain this table RTP monitors must have an entry for each pair sender receiver in the sessions being monitored D COMPATIBILITY WITH JMF STATISTICS Appendix E is a table that compares the fields in the RTP MIB tables with the JME statistics used by RTPMonitor This comparison has two objectives e Detect what MIB statistics are not supplied by JMF If JMF does not supply all the required MIB data an RTP MIB agent can n
55. Figure 3 4 RTCP Sender Report SR Format Schulzrinne et al 99 25 Padding P 1 bit If padding bit is set the packet contains one or more additional padding bytes The last byte contains the number of padding bytes including itself The padding bytes are included in the length field Only the last packet of a compound packet can use padding Reception report count RC 5 bits The number of reception report blocks contained in this packet Packet type PT 8 bits It is set to 200 to identify a SR packet Length 16 bits The length of the SR packet in 32 bit words minus one including the header and any padding SSRC 32 bits The synchronization source identifier for this originator of this SR packet NTP timestamp 64 bits Indicates the wallclock time when this report is sent The wallclock represents the absolute day and time using the timestamp format of the Network Time Protocol NTP described in RFC1305 The full resolution NTP timestamp is a 64 bit unsigned number with 32 bits for the integer part and 32 bits for the fractional part It represents the number of seconds relative to Oh UTC on 1 January 1900 RTP timestamp 32 bits Corresponds to the same time as the NTP timestamp above but in the same units and with the same random offset as the RTP timestamp in data packets This correspondence may be used for intra media and inter media synchronization for sources whose NTP timestamps are synchronized
56. Management Information Base MIB defines Simple Network Management Protocol SMNP objects for managing RTP systems This work is produced by the Audio Video Transport AVT Group of the Internet Engineering Task Force IETF Baugher et al 99 as broad guidance for all applications collecting RTP statistics This chapter describes some basic concepts of the RTP MIB and compares its attributes with the existing set of Java Media Framework used by the rtpMonitor application B NETWORK MANAGEMENT OVERVIEW A network management system is a collection of tools for networking monitoring and control including hardware and software Stallings 97 The key elements of a network management system are e Management station the interface to the network manager e Agent responds to requests for information and for taking actions Typically the agent software is installed in routers bridges hubs and hosts e Management information base MIB represents a collection of objects data variables managed by agents e Network management protocol links the management station with the agents The Simple Network Management Protocol SNMP is the most widely management protocol in use for TCP IP networks SNMPv2 version 2 is described in 65 RFC 1901 Case et al 96 SMNP include mechanisms for retrieving data from agents set values of objects on agents and notify the management station of significant events C RTP MIB D
57. Media Locator that be used to create a Processor Figure 4 6 contains a UML collaboration diagram that describes a JMF procedure to capture the media and transmit it in a RTP session CaptureDevice di CaptureDevicelnfo Manager Manager 1 di getDevice format 7 2 loc getLocator 8 0 3 proc createProcessor loc 4 tc getTrackControls gt proc Processor gt 6 ds getDataOutput 5 setFormat RTP_format 7 createSendStream ds ts tc TrackControl RTPSessionManager Figure 4 6 Media Capture and Transmission Collaboration Diagram 32 10 RTP Statistics JMF maintains several statistics about the RTP session and its streams Statistics about the session as a whole are obtained through the RTPSessionManager by the methods getGlobalTransmissionStats and getGlobalReceptionStats These methods retrieve GlobalReceptionStats and GlobalTransmissionStats objects respectively which have methods to get each statistic Individual stream statistics are maintained within RTPSendStream and RTPRecvStream objects by the RTPTransmissionStats and RTPReceptionStats interfaces Figure 4 7 contains a UML class diagram showing the classes mentioned above Interf ace gt gt RTPSessionManager tai mantains Interf ace getGlobalReceptionStats GlobalReceptionStats getSendStreams
58. NAVAL POSTGRADUATE SCHOOL MONTEREY CALIFORNIA THESIS VIRTUAL REALITY TRANSFER PROTOCOL VRTP IMPLEMENTING A MONITOR APPLICATION FOR THE REAL TIME TRANSPORT PROTOCOL RTP USING THE JAVA MEDIA FRAMEWORK JMF by Francisco Afonso September 1999 Thesis Advisor Don Brutzman Second Reader Don McGregor Approved for public release distribution is unlimited REPORT DOCUMENTATION PAGE Public reporting burden for this collection of information is estimated to average 1 hour per response including the time for reviewing Searching existing data sources gathering and maintaining the data needed and completing and reviewing the collection of information Send comments regarding this burden estimate or any other aspect of this collection of information including suggestions for reducing this burden to Washington Headquarters Services Directorate for Information Operations and Reports 1215 Jefferson Davis Highway Suite 1204 Arlington VA 22202 4302 and to the Office of Management and Budget Paperwork Reduction Project 0704 0188 Washington DC AGENCY USE ONLY Leave blank 2 REPORT DATE 3 REPORT TYPE AND DATES COVERED September 1999 Master s Thesis TITLE AND SUBTITLE 5 FUNDING NUMBERS Virtual Reality Transfer Protocol vrtp Implementing a Monitor Application for the Real time Transport Protocol using the Java Media Framework JMF AUTHOR Francisco Afonso PERFORMING ORGANIZATION NAME S AND AD
59. Sender s packet count 32 bits The total number of packets transmitted by the sender since starting transmission until the time the SR packet was generated The count should be reset if the sender changes its SSRC identifier Sender s byte count 32 bits The total number of payload octets i e not including header or padding transmitted in the RTP data by the sender since starting the transmission until this SR packet was generated The count should be reset if the sender changes its SSRC identifier SSRC n 32 bits The SSRC identifier of the source to which the information in this block pertains Fraction lost 8 bits The fraction of RTP data packets from source SSRC_n lost since the previous SR or RR packet It is represented as a fixed point number with the binary point at the left edge of the field 26 Cumulative number of packets lost 24 bits The total number of RTP data packets from source SSRC_n that have being lost since the beginning of the reception e Extended highest sequence number received 32 bits The low 16 bits contain the highest sequence number received in an RTP data packet from source SSRC_n The most significant 16 bits extend that sequence number with the corresponding count of sequence number cycles e Interarrival jitter 32 bits An estimate of the statistical variance of the RTP data packet interarrival time measured in timestamp units and expressed as an unsigned integer e Last SR times
60. TP There is an Internet Draft containing guidelines to be followed by Payload Format Specification Documents Handley 99 Several payload format specifications were proposed so far most of them related to audio and video encodings Below is a list of payload format RFCs and Internet Drafts 2032 RTP Payload Format for H 261 Video Streams RFC 2029 RTP Payload Format of Sun s CellB Video Encoding 2190 RTP Payload Format for H 263 Video Streams 2198 RTP Payload for Redundant Audio Data 34 e 2250 RTP Payload Format for MPEGI MPEG2 Video e 2343 RTP Payload Format for Bundled MPEG 2429 RTP Payload Format for the 1998 Version of ITU T Rec H 263 Video 2431 RTP Payload Format for BT 656 Video Encoding 2435 RTP Payload Format for JPEG Compressed Video RTP Payload for Dial Tone Multi Frequency DTMF Digits RTP Payload Format for X Protocol Media Streams RTP Payload Format for MPEG 4 Streams RTP Payload Format for User Multiplexing RTP Payload Format for Reed Solomon Codes RTP Payload Format for Interleaved Media RTP Payload Format for Telephone Signal Events RTP Payload Format for DVD Format Video Other RTP related RFCs and Internet Drafts include RFC 2354 Options for Repair of Streaming Media RFC 2508 Compressing IP UDP RTP Headers for Low Speed Serial Links Real Time Protocol Management Information Base Sampling the Group Membership i
61. Total Packets RTCP Packets SR Packets Bad RTP Packets Bad RTCP Packets Bad SR Packets Bad RR Packets Bad SDES Packets Bad BYE Packets Local Collisions Remote Collisions Looped Packets Failed Transmission Unknown Type Label rLab TextField rText String rField Lost PDUs Processed PDUs MisOrdered PDUs Invalid PDUs Duplicate PDUs j int endsInHours 1 2 4 8 12 24 48 168 String locator boolean flgPart flgPlay flgRecord boolean flgActive false int presInterval double recInterval RtpMonitorManager monMgr SessionManager mymgr DisplayTask dispTask long SSRCtoShow Hashtable streamTable boolean flgUpdateStreams 163 Date endDate MenuBar bar Menu preferences bookmarkMenu filesMenu helpMenu Menultem viewPref modifyPref selectBm addBm deleteBm aboutItem Menultem last5Item previousSItem lastHourItem previousHourItem headerItem MenuItem exitItem ModifyPreferences modPrefDialog SelectBookmark selBmDialog DeleteBookmark delBmDialog AddBookmark addBmDialog About aboutDialog Constructor It is called by main if no command line argument is passed p The constructor initializes the GUI components public RtpMonitor super RtpMonitor setSize 780 530 setLayout null preferences new Menu Preferences viewPref
62. Window theParent RtpMonitor parent loadBookmarks sessionAddLabel new Label Session Address sessionAddLabel setBounds 10 40 100 25 sessionAddLabel sessionAddRealLabel new Label theParent sessionText getText sessionAddRealLabel setBounds 115 40 230 25 sessionAddRealLabel sessionNameLabel new Label Session Name sessionNameLabel setBounds 10 80 100 25 sessionNameLabel sessionNameText new TextField theParent sessionNameText getText sessionNameText setBounds 110 80 230 25 sessionNameText 138 addButton new Button Add addButton setBounds 100 130 60 25 addButton addActionListener this addButton cancelButton new Button Cancel cancelButton setBounds 200 130 60 25 cancelButton addActionListener this add cancelButton Takes action when buttons are selected public void actionPerformed ActionEvent if e getSource addButton String sessAdd theParent sessionText getText trim String sessName sessionNameText getText trim if sessName equals sessionNamesVec addElement sessName sessionAddressVec addElement sessAdd saveBookmarks theParent sessionNameText setText sessName setVisible false if e getSource cancelButton setVisib
63. a has three subversions available e Pure Java includes binaries written entirely in the Java programming language that can be installed on any operating system supported by the Java platform e Solaris Performance Pack an optimized version for the Solaris platform that includes binaries for this operating environment e Windows Performance Pack an optimized version for the Windows platforms that includes binaries for this operating environment rtpMonitor was tested only in Windows NT platforms using the Windows Performance Pack The program was tested in all its functionality with special emphasis on the recording capabilities It proved to be robust running continuously for the maximum allowed session duration one week several times It has generated correct output files of more than 40 Mbytes for a single session 69 C OBSERVED PROBLEMS Several errors i e software bugs were detected in JMF 1 0 through the development of rtpMonitor The following errors were reported in the JMF mailing list and were corrected in JMF2 0 Early Access e The number of lost PDU in the stream data was usually wrong It returned a high number of lost PDU even greater than the actual number of packets sent by the source e When a non participating option had been selected the information about the active and passive participants was inconsistent Usually no participants were presented even though they might have existed e Individual vide
64. ad thread setDaemon true thread start 145 This method runs continuously calling the showStats methods of RtpMonitor in the proper presentation interval until the RtpMonitor stops the session public void run while myMon isMonitoring showGlobalStats ShowParticipants sSshowStreamStats showFeedbacks myMo myMo myMo myMo PY YP 23 try Thread sleep intervalParam catch InterruptedException e end of class DisplayTask 146 package org web3d vrtp rtp import java io import java util A class used by RecordTask objects to organize statistics in several files five minutes hour and day lt P gt This class writes to the file following files statisticsLastFiveMinutes txt statisticsPreviousFiveMinutes txt statisticsLastHour txt statisticsPreviousFiveMinutes txt and statisticsDateMM DD YYYY txt author Francisco Afonso afonso cs nps navy mil version 1 0 X ox Xo Xo X public class FileCatalog Calendar rightNow String prefix String dateRef int minuteRange hourRange boolean flgFirstDataMin File min5 min5last hour hourlast header Constructor It checks if there are previous data from the same session and transfers these data to the correct statisticsDateMM DD YYYY txt file Then it clears all five minutes and h
65. age org web3d vrtp rtp import java awt event This class is used to set a frame dialog as not visible when the close icon is clicked author Francisco Afonso afonso cs nps navy mil version 1 0 public class CloseWindow extends WindowAdapter set frame dialog as not visible This method is activated when the window is closed public void windowClosing WindowEvent e getWindow setVisible false end of class CloseWindow 141 package org web3d vrtp rtp impor impor impor impor java awt java awt event java util java io V fr rV T A Dialog to delete a session bookmark P author Francisco Afonso afonso cs nps navy mil version 1 0 public class DeleteBookmark extends Dialog implements ActionListener X X X java awt List sessionNamesList Vector sessionAddressVec Button deleteButton cancelButton Constructor lt P gt param parent the parent frame public DeleteBookmark Frame parent super parent Delete Bookmark true setSize 250 300 setLayout null setBackground Color lightGray addWindowListener new CloseWindow sessionNamesList new java awt List 5 false sessionNamesList setBounds 10 30 230 210 loadBookmarks add sessionNamesList deleteButton new Button Delete deleteButton setBounds 50 260 6
66. alParticipants it very well may be rtpSessionSenderJoins rtpSessionReceiverJoins Not provided by MIB RemoteParticipants int the number of Desirable remote participants attending the session Bill Strahm comments Can simply be the count of receivers in the receiver table 193 Not provided by MIB ActiveParticipants int the number of Needed active participants senders attending the Bill Strahm comments See above session Not provided by MIB TotalBytesRecd int the number of Needed for bandwidth calculations bytes received in the session before any Bill Strahm comments rtpRcvOctets in validation the receiver table Not provided by MIB TotalPacketsRecd int the total number Needed for comparison of bandwidth of RTP and RTCP packets received in the versus packets per second performance session before any packet validation Bill Strahm comments rtpRcvPackets the receiver table Not provided by MIB RTCPPacketsRecd int the total Desirable number of RTCP packets received in the Bill Strahm comments Combination of session before any header validation SR RR counts out of the sender receiver table Not provided by MIB SRPacketsRecd int the total number Desirable of sender reports received in the session Bill Strahm comments rtpSenderSR from the sender table Not provided by MIB BadRTPPackets int the total number Desirable
67. and monitoring components JMF is a possible solution for the implementation of the RTP protocol in vrtp JMF is a free package and is an approved extension of the Java language application programming interface API C OBJECTIVES The goal of this thesis is the implementation of a monitor application for the Real time Transport Protocol RTP using Java Media Framework JMF An RTP monitor is an application that receives packets sent by all participants in order to estimate the quality of service for distribution monitoring data recording statistics analysis and fault diagnosis Schulzrinne et al 99 The emphasis is in both short term and long term statistics by having recording capabilities for future analysis As a result of this work an example set of classes for monitoring RTP sessions can be provided to vrtp applications D THESIS ORGANIZATION The remaining chapters of this thesis are organized as follows Chapter II describes work related to RTP monitoring Chapter III presents the RTP protocol functionality and packet formats Chapter IV provides an overview of the JMF architecture with emphasis on the RTP classes Chapter V describes the design and implementation of the RTP monitor application and the interdependency between the RTP Monitor and JMF classes Chapter VI contains a study of compatibility between JMF statistics and the proposed RTP Management Information Base MIB Baugher et al 99 Chapter VII contains
68. asses were developed by Sun RtpPlayerWindow came with JMF1 1 sample code and PlayerWindow is in the file jmf jar 61 From JMF API RtpSessionAddress from session creates RtpMonitorManager we odes from rtp N lt lt Interface gt gt RTPMonitorManager update creates __ Pa e 7 from session close 1 getMediaLocator getSessionManager getSessionAddress N creates N RecordTask from rtp RecordTask exit run recordGlobalStats recordStreamStats recordFeedbacks 1 Itis a new thread Records the last creates report PlayerWindow from ui V 1 FileCatalog from rtp FileCatalog Manages the transfers update __ between the several FromJMF N concatenate output files API saveDateRef retrieveDateRef Figure 5 4 RTPMonitorManager UML Class Diagram 62 4 RtpMonitor The main RtpMonitor class extends a Frame and implements the rtpMonitor Graphical User Interface GUI RtpMonitor and RtpMonitorCommandLine can be considered classes in the application level They use the services of RtpMonitorManager to provide some user level functionality RtpMonitor has the following functions e Collects user preferences It uses the ModifyPreference class as the dialog box e Selects ad
69. atic monitoring capability in vrtp sessions For this purpose the rtpMonitor library must be updated to support transmission statistics and direct activation by vrtp components This is a good area of study for agent based network monitoring diagnosis and problem correction 8 Design Patterns Course in Computer Science Curriculum Design Patterns study helps to solve recurring design problems by using common adopted solutions Furthermore the Design Patterns nomenclature provides a precise way of communicating design ideas among software engineers The inclusion of a Design Patterns course in the Computer Science and MOVES Curricula is highly recommended 75 THIS PAGE LEFT INTENTIONALLY BLANK 76 APPENDIX A PREPARING UML DIAGRAMS USING RATIONAL ROSE UML Diagrams Preparation Rational Rose version 98i can represent the following types of UML diagrams Use Case Diagrams Class Diagrams Collaboration Diagrams Sequence Diagrams Component Diagrams Deployment Diagrams The program is capable of handling different models projects each model being a set of basic components classes interfaces actors and associations and diagrams For better visualization the project is organized in a tree like structure having the following main branches e Use Case View usually contains the Use Case Diagrams and actors components Logical View usually contains the Class Diagrams Collaboration Diagrams Sequence Diagrams Class C
70. ation by searching for new participants in the list of participants managed by RTPSessionManager SessionByes Counter32 a count of RTCP Not implemented Not part of native JMF statistics It can be BYE derived in an JMF application by monitoring ByeEvents SessionStartTime TimeStamp the value of Not implemented That is the time when the Session SysUpTime at the time that this row is Monitoring starts It can be added to created RTPMonitor SessionMonitor Thuth Value set to true if Not applicable In RTP Monitor it is always true sender or receivers in addition to the local RTP System are to be monitored SessionRowsStatus RowStatus active when Not implemented It can be implemented in RTP Monitor but RTP RTCP Messages are being sent or without removals received by an RTPSystem If this row is notInService it may be removed after 5 minutes Not provided by MIB Time hh mm ss time of the report Needed Implicit in SNMP Bill Strahm comments Times of the reports are in the sender receiver report tables Not provided by MIB TotalParticipants int the total number Needed Equals active passive participants and of participants attending the session also remote local Bill Strahm comments We argued about whether we should track Sender Receiver Joins Byes as a high watermark a total count or a current count We decided on the counter Depending on how you want to track Tot
71. case of the sender requested was requested in the jmf interest mailing list RcvrPT Integer static or dynamic payload Not provided by JMF type from the RTP header RevrPackets Counter64 count of RTP packets Not implemented Called ProcessedPDU by JMF number of received by this RTP host since RcvrStartTime valid packets received from the selected source Same as SenderPackets in the SenderTable RcvOctets Counter64 count of RTP octets Not implemented Not provided by JMF Same as received since RcvrStartTime SenderOctets in the SenderTable RcvStartTime TimeStamp the value of Not implemented It can be added SysUpTime at the time that this row is created 198 APPENDIX F RTPHEADER JAVADOC The RtpHeader Javadoc is available at http www web3d org WorkingGroups vrtp javadoc dis java vrml mil navy nps dis RtpHeader html 199 APPENDIX G RTPHEADER SOURCE CODE package mil navy nps dis import mil navy nps util import java io This class encapsulates the header of the Real time Transport Protocol RTP when used to transfer DIS packets as a payload version 1 0 author Francisco Afonso afonso cs nps navy mil lt dt gt lt b gt References lt b gt lt dd gt RTP RFC1889 a href http www ietf org internet drafts draft ietf avt rtp new 04 txt http www ietf org internet drafts draft ietf avt rtp new 04 txt a o X F X X
72. cking on a data element in the main table brings up charts for each of the statistics values that rtpmon tracks Two Steves Michael Van Norman UCLA Robert Elz Melbourne Michael Van Norman UCLA Don Brutzman mvn 164 67 182 253 Hikan Lennestll Erisoft AB Lulel Sweden srcid 294851760 eee address 164 67 182 253 jer m ripmon menu email mvnGclibrary ucla edu tool 2 7 32 Display parameter 2 Last control packet 14 35 22 Threshold E Jitter Dismiss Sorting Sort receivers by Piipchart Steve Deering Xer Maximum Loss Receiver Steve Deering Xerox PARC Average Loss IP address Sender Two Steves Autosort interval 5 eters 0 0 Session 20 0 Jitter Dest 224 2 204 138 60856 aKey Dismiss Dismiss 100 0 Loss Percentage Figure 2 3 Rtpmon graphical user interface GUI 10 4 Multi MON MultiMON is a client server monitor that collects organizes and displays all the IP multicast traffic that 1s detected at the location of a server Robinson et al 96 It was developed by the Communications Research Center at Ottawa Last release was version 2 0 in July 1998 It can be downloaded at ftp debra dgbt doc ca pub mbone multimon MultiMON is a general purpose multicast monitoring tool It is intended to monitor multicast traffic on local area network LAN segments a
73. col vrtp a protocol being developed to support large scale virtual environments LSVEs over the Internet Initial test results are satisfactory for audio and video streams as well as prototype RTP compliant Distributed Interactive Simulation DIS protocol streams Future work includes automated monitoring across WANs and standardizing structured data formats to comply with Management Information Base MIB requirements using Extensible Markup Language XML 14 SUBJECT TERMS 15 NUMBER OF PAGES Multicasting Real time Transport Protocol Virtual Reality Java 232 17 SECURITY CLASSIFICATION 18 SECURITY CLASSIFICATION 19 SECURITY CLASSIFICATION 20 LIMITATION OF OF REPORT OF THIS PAGE OF ABSTRACT ABSTRACT Unclassified Unclassified Unclassified UL NSN 7540 01 280 5500 Standard Form 298 Rev 2 89 Prescribed by ANSI Std 239 18 298 102 ii Approved for public release distribution is unlimited VIRTUAL REALITY TRANSFER PROTOCOL VRTP IMPLEMENTING A MONITOR APPLICATION FOR THE REAL TIME TRANSPORT PROTOCOL RTP USING THE JAVA MEDIA FRAMEWORK JMF Francisco Carlos Afonso Lieutenant Commander Brazilian Navy B S E E University of Sao Paulo 1988 Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN COMPUTER SCIENCE from the NAVAL POSTGRADUATE SCHOOL September 1999 Author Francisco Carlos Afonso Approved by Don Brutzman Thesis Advisor Don McGregor Second Reader
74. creates a FileCatalog object that will organize the data in several files five minutes hour and day param mon the RtpMonitorManager that manages the monitoring session lt P gt param recInterval the interval between statistic samples in seconds public RecordTask RtpMonitorManager mon double recInterval saves parameters as internal variables myMon mon recordParam int recInterval 1000 gets the session manager associated with the monitoring session mgr myMon getSessionManager 155 gets session address and port String session myMon getMediaLocator getSessionAddress String port new Integer myMon getMediaLocator getSessionPort toString creates a new subdirectory for saving session statistics dir new String session session replace port port File newdir new File dir newdir mkdir creates file statisticsLastReport txt prefix new String dir statistics filename new String prefix LastReport txt creates a FileCatalog object cat new FileCatalog prefix executes as a thread thread new Thread this Record thread thread setDaemon true thread start Resets a flag that is checked each time the thread associated with this object is awaken after the wait command causing the thread to end A public void exit flgRun false Starts executing the recordin
75. creates new RTPSendStream objects when the method createSendStream is called using a DataSource object as argument 2 RTP Participants RTPParticipant is an interface that represents one participant in an RTP session A participant may be the source of zero or more streams The method getStreams returns a vector containing all RTPStream objects owned by the participant RTPParticipant has two sub interfaces RTPRemoteParticipant and RTPLocalParticipant These are only marker interfaces with no extra functionality The RTPSessionManager creates a new RTPRemoteParticipant whenever a new RTCP packet arrives that contains a CNAME that has not been seen before The association between the RTPParticipant object and a RTPRecvStream is done using the SSRC identifier It is possible to have an unassociated RTPRecvStream as the source can start sending RTP packets before a CNAME RTCP packet is sent A participant that sends no data is called a Passive Participant Otherwise it is called an Active Participant The method getAllParticipants of RTPSessionManager returns a vector with all RTPParticipants Similar methods exist to return vectors with remote local active and passive participants RTCP Source Description RTCPSourceDescription is a class that contains one description information related to a participant as received by the RTCP SDES packets So associated with a RTPParticipant object there may be several RTCPSourceDescription objects
76. d in RFC2279 This field is continuous and it is not limited to a 32 bit boundary The field must be terminated with a null octet and followed by zero or more null octets until the next 32 bit boundary This kind of padding is separated from the one specified with the Padding bit in the header Canonical name is the only mandatory SDES item It must be sent on each RCTP packet As the canonical name will be used to identify a participant in single and multiple RTP sessions it must be unique CNAME will be use to solve collisions with the SSRC identifiers A participant may have multiple SSCR identifiers one for each related session he is in but he must have only one CNAME As CNAME should provide information in order to locate a source its recommended formats are user full hostname or user Q Paddress 3l 4 Goodbye BYE The BYE packet indicates that one or more participants are no longer active The packet has the format shown in Figure 3 9 0 3 8 16 31 V P 5 PT 203 BYE length SSRR 1 CSRC 1 SSRR 2 CSRC 2 length reason for leaving Roane Figure 3 9 BYE Packet Format Schulzrinne et al 99 The header section has the same format of the previous RTCP packets Following the header there is list of all participants that are leaving the section The reason for providing the capability for more than one source in the BYE packet is the Goodbye packet sent by a mixer If a mixer shuts down it mu
77. d line arguments have the following format java RtpMonitorCommandLine rtpLocator options lt P gt rtpLocator example rtp 224 2 125 50 50328 127 lt P gt i nnn nnn defines the recording interval in seconds default 30s lt P gt e ppp ppp defines the monitoring duration in hours default 168 help displays command line format and aborts lt P gt param args an array of strings 5 public RtpMonitorCommandLine String args int nArgs args length if nArgs 0 System out pri System out pri System out pri options System out pri System out pri System out pri rtpLocator ntlin Format java RtpMonitorCommandLine rtpLocator lt options gt ntlin example rtp 224 2 125 50 50328 127 ntln part monitor sends packets ntin play monitor play streams ntlin record monitor records statistics ntlin i nnn nnn defines the recording interval in seconds default 30s ppp ppp defines the monitoring duration in hours e default 168 hs System out pri Ln help displays command line format and aborts System exit 0 if args 0 indexOf help 0 System out println System out pri rtpLocato System out pri options System out pri System out pri System out pri System exit 0 Format java nu I n Oto bao
78. ds and deletes bookmarks It uses the SelectBookmark AddBookmark and DeleteBookmark classes as dialog boxes e Displays statistics periodically It creates a DisplayTask object which is a new thread that sleeps for a user defined time to call its methods for updating the statistics on screen 5 RtpMonitor Applet A good idea might be to make an applet version in a web page To do this security problems must be addressed as the monitor must write data to disk and open network connections The implementation of an RTP Monitor version running as an applet was left as future work 6 RtpMonitorCommandLine RtpMonitorCommandLine objects are instantiated by the main method of RtpMonitor when some parameter is passed This class performs the creation of a RTPSessionManager object but does not present statistics on screen Several options can be passed by the command line call to RtpMonitor They are basically the same available in RtpMonitor preferences dialog 63 D SUMMARY The rtpMonitor application allows the monitoring of an RTP session by presenting session and stream statistics on screen as well as recording statistics on files for future analysis The program also supports Media presentation of audio and video The design goal of the rtpMonitor was to provide a basic set of classes for RTP statistics recording with minimal interfacing with JMF 64 VI RTP MANAGEMENT INFORMATION BASE MIB A INTRODUCTION The RTP
79. eam RTPRecvStreamListener gt stream RTPRecvStream 3 ds getDataSource 5 create player 4 player createPlayer ds Manager PlayerWindow Figure 4 5 RTP Media Presentation Collaboration Diagram Numbered arrows indicate the sequence of method calls occurring between objects 9 Transmitting RTP Streams RTP stream can be transmitted by passing a DataSource object to the Session Manager using the method createSendStream As a DataSource can contain multiple streams tracks an index of the stream must be specified The DataSource is usually obtained as an output of a Processor In this case the Processor has to generate RTP encoded data because the Session Manager does not perform that function So each track to be transmitted has to be set to an RTP specific format The method setFormat of the TrackControl interface allows a Processor to set the format of a track If the format can not be applied to the track an IncompatibleFormatException is thrown 51 If the physical source of the stream is intended to be camera or microphone a CaptureDeviceInfo object must be created by using the method getDevice of CaptureDeviceManager The argument passed to the method getDevice is a Format object which describes a media format The CaptureDeviceManager searches for a device in the system that supports the desired format The method getLocator of CaptureDeviceInfo returns a
80. eceiveStreamListener this windowlist new Hashtable gets the InetAddress of the session InetAddress destaddr InetAddress getByName rtpml getSessionAddress gets the session port int port rtpml getSessionPort creates a SessionAddress objet to represent the session sessaddr new SessionAddress destaddr port destaddr 1 call the method to generate a CNAME for the user String cname mgr generateCNAME gets the username from the system and adds it to the string rtpMonitor That will be the user name sent in RTCP packets String username null try username System getProperty user name rtpMonitor catch SecurityException e username RTPMonitor user creates the source description fields SourceDescription userdesclist new SourceDescription 3 userdesclist 0 new 182 ju SourceDescription SourceDescription SOURCE username 1 false ESC NAME userdesclist 1 new SourceDescription SourceDescription SOURCE DESC CNAME cname 1 false userdesclist 2 new SourceDescription SourceDescription SOURCE DESC TOOL RTPMonitor v1 0 1 false generates a local address SessionAddress localaddr new SessionAddress that is the fraction of RTCP bandwith compared to RTP double rtcpFraction 0
81. ed to change the session address and preferences before starting monitoring again 8 Recording monitoring data A new subdirectory is created for each session address with the following name session IPaddress port port number Inside this subdirectory several files will be generated and updated during a recording session They are statisticsHeader txt contains the description of the fields being stored statisticsLastFiveMinutes txt contains the last five minutes block of statistics statisticsPreviousFiveMinutes txt contains the previous five minutes block of statistics statistics LastHour txt contains the last hour block of statistics statisticsPreviousHour txt contains the previous hour block of statistics statisticsDateMM DD Y Y Y Y contains statistics taken in described date statistics LastReport txt contains the last single report There is also a file called LastDateRef txt which contains the last monitoring date for that session It is possible to see some of these files using the menu File 85 RtpMonitor 1 2 Bookmarks Preferences Help Last five minutes Previous five minutes 2 203 37 60068 127 Session Name Nasa TY from video Start Stap Last hour Global Statistics Bad SDES Packets Stream Bad BYE Packets T Lost PDUs Local Collisions s Processed PDUs SR Packets Remote Collisians MisOrdered PDUs Bad RTP Packets Looped Packets
82. ediaLocator describes the location of a media content A MediaLocator is closely related to an URL but identifies stream parameters e DataSource represents the media itself A DataSource encapsulates the media stream much like videotape does for a video movie This class is created based on a Media Locator e Player provides processing and control mechanisms over a DataSource just like a VCR does for a videotape A Player can also render the media to the appropriate output device e g monitor or speakers e Processor is a specialized type of Player that provides control over what processing is done on the input media stream Processor supports a programmatic interface to control the processing of the media data and also provides access to the output data streams DataSink represents an output device other than a monitor and speaker the most common destinations for media output For example a DataSink can be used to save the media to a file or to retransmit to a network 38 e Manager handles the construction of Player Processor DataSource and DataSink objects Figure 4 1 shows some possible connections between the above elements Part a is the configuration used to play a media stream In part b we see a processor creating a DataSource object from another DataSource In part c a DataSource is passed to a DataSink that writes it to a file Note that multiple DataSource objects can be connected via Processors
83. elp Session Address 1224 2 220 5 56414 127 Session Name Dis Java vimi video Start Global Statistics Total Bytes Bad SDES Packets stream z Total Packets Bad BYE Packets Sram zm Lost PDUs RTCP Packets Local Collisions Processed PDUs SR Packets Remote Collisions MisOrdered PDUs Bad RTP Packets Looped Packets o Invalid PDUs Bad RTCP Packets Failed Transmission Duplicate PDUs Bad SR Packets Unknown Type Bad RR Packets Active Participants Passive Participants Username Fraction Lost Jitter Packets Lost Feedback Reports Figure 5 1 rtpMonitor Main Window 2 Statistics Display The program periodically displays the following information e Global statistics general reception information about the whole session e Stream statistics about the reception of a single stream 56 Feedback the RTCP Receiver Report information from all participants about the stream being monitored 3 Statistics Recording rtpMonitor can record statistics in text files using a recording interval defined by the user Several files are created and managed to simplify further retrieval There are files to hold data from the last five minutes previous five minutes last hour previous hour and different dates Multiple file sizes and periodicities are employed to avoid excessive file sizes when performing extended monitoring File name conventions are presented in
84. er audio or video by launching audio video playback windows All Unified Modeling Language UML diagrams in this chapter conform to the UML Specification Booch 97 and were prepared using the Java to UML facilities of Rational Rose 981 Rational 99 B RTPMONITOR FUNCTIONALITY AND INTERFACE This section contains a summary of the rtpMonitor functionality Additional information can be found in the Appendix B the rtpMonitor User Manual 1 Graphical User Interface GUI Figure 5 1 shows the rtpMonitor main window In the Bookmark menu the user can select add or delete a bookmark related to the session name address In the Preferences menu the user can select whether the monitor will participate in the session play streams and or record statistics The user can also be selected the duration of the monitoring session the recording interval and the presentation interval In the Output files menu the user can launch an external viewer to see the contents of the statistic files generated by the program 55 The upper part of the window contains the session address according the RtpMediaLocator format and the session name The user enters the session name when a new bookmark is inserted This name does not necessarily have any relation with the session name of the Session Description Protocol SDP announcements The rest of the window contains the current RTP statistics RtpMonitor OF x File Bookmarks Preferences H
85. es cece eee aS SSRR_2 SSRC of the first source profile specific extensions Figure 3 6 Receiver Report RR Format Schulzrinne et al 99 3 Source Description SDES The SDES packet consists of a header section and zero or more chunks of data Each chunk is composed of items describing the source identified in that chunk The SDES packet format is shown in Figure 3 7 29 e 3 8 16 31 SC V P PT 202 SDES length SSRR 1 CSRC 1 SDES items SSRR 2 CSRC 2 SDES items Figure 3 7 Source Description SDES Packet Format Schulzrinne et al 99 The fields in the SDES packet are e Version V Padding P and length As described for SR and RR packets e Packet type PT 8 bits It is set to 202 to identify a SDES packet e Source count SC 5 bits The number of SSRC CRCS chunks contained in this packet The SDES item format is shown in Figure 3 8 8 16 n type length content Figure 3 8 SDES Item Format Schulzrinne et al 99 The fields in each SDES item are e Type 8 bits Contains a value to identify a type of description The following values are defined in RFC1889 Canonical Name 1 Name 2 Email 3 Phone 4 Location 5 Tool 6 Note 7 Private Extensions 8 e Length 8 bits The length of the chunk content in bytes e Content Consists of text encoded in UTF 8 encoding specifie
86. et header format for MBone application streams Using RTP a multicast session between several participants can be established making possible the correct synchronization of the exchanged media and the feedback of each participant about the quality of reception The RTP Control Protocol RTCP performs the feedback and control mechanisms of RTP Java Media Framework JMF is a new Java Application Programming Interface API developed by Sun and other companies to allow Java programmers use multimedia features in applications and applets Sun 99 JMF supports RTP transmission and reception of audio and video streams This thesis examines network monitoring issues relevant to RTP through implementation and testing of a JMF application B MOTIVATION Since its inception RTP has been mostly used in audio and video conferences However a diverse set of multicast applications can take benefit of RTP mechanisms for synchronization such as exchanging simulation data over a wide area network WAN RTP is particular important because it is used by backbone routers to support Quality of Service QoS related performance optimization The Virtual Reality Transfer Protocol vrtp is developed to provide client server multicast streaming and network monitoring capabilities in support of internetworked 3D graphics and large scale virtual environments LSVEs Brutzman 99 RTP is an integral part of the vrtp architecture used in both the streaming
87. eyor August 1997 Agarwal Deb Rtpmon Information http www itg Ibl gov mbone rtpmon tips html June 1997 Apple Computer Inc Quicktime 4 http www apple com quicktime August 1999 Baugher Mark and others Real Time Transport Protocol Management Information Base Internet Draft draft ietf avt rtp mib 05 txt Internet Engineering Task Force 12 April 1999 Available at http www ietf org internet drafts draft ietf avt rtp mib 05 txt Booch G Jacobson I and Rumbaugh J UML Specification version 1 1 1 September 1997 Available at http www rational com uml index jtmpl Brutzman D P Virtual Reality Transfer Protocol vrtp http www web3d org WorkingGroups vrtp June 1999 Case J McCloghrie K and others Introduction to Community based SNMPv2 RFC 1901 SNMP Research Inc Cisco Systems Inc Dover Beach Consulting Inc International Network Services January 1996 David B rtpmon A Third Party RTCP Monitor http bmrc berkeley edu drbacher projects mm96 demo index htm September 1996 Deering S E Host Extensions for IP Multicasting RFC 1112 August 1989 Gamma E and others Design Patterns Elements of Reusable Object Oriented Software Addison Wesley Pub Co 1995 Grand M Patterns in Java John Willey amp Sons Inc 1998 Handley M and Perkins C Guidelines for Writers of RTP Payload Format Specifications Internet Draft draft ie
88. g and waiting until the recording interval is over in a loop until the exit method is called 5y public void run flgRun true runs continuously until stopped while flgRun try opens the last report file output new PrintStream new FileOutputStream filename false gets actual time timeNow Calendar getInstance records statistics on file recordGlobalStats recordStreamStats 156 recordFeedbacks calls the FileCatalog object to manage the data between the several files cat try update timeNow catch FileNotFoundException e System out println In RecordTask 4 getMessage finally output close Thread sleep recordParam catch InterruptedException e Records global statistics lines starting with D1 x private void ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou ou tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu tpu t t Ge ce cE ct Cher OCR a ch cCESCR CE CES LA cb chock ck ch CE Cf prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin prin recordGlobalStats GlobalReceptionStats stats
89. g username getUsername part if username null return part getCNAM 0 else return username Converts an number represented as a signed integer 32 bits to a long integer 64 bits JMF methods return the SSRC as an integer As the SSRC is a 32 bits number some are represented in JMF as negative integers This convertion is necessary to present SSRCs as a positive integer public static long correctSSRC long ssrc if ssre lt 0 return 42949672961 ssrc 4 X X return ssrc end of class RtpUtil 188 package org web3d vrtp rtp import java awt import java awt event import java util import java io A Dialog to select a session bookmark It displays a list choice of session names p author Francisco Afonso afonso cs nps navy mil version 1 0 public class SelectBookmark extends Dialog implements ItemListener java awt List sessionNamesList Vector sessionAddressVec RtpMonitor theParent Constructor lt P gt param parent the parent frame public SelectBookmark Frame parent super parent Select Bookmark true setSize 250 200 theParent RtpMonitor parent addWindowListener new CloseWindow sessionNamesList new java awt List 5 false loadBookmarks sessionNamesList setBackground Color lightGray sessionNamesList addItemListene
90. gPlay flgRecord recInterval mymgr monMgr getSessionManager catch MalformedURLException e fFeedbkArea setText MalformedURLException creating RtpMonitorManager n feedbkArea append e getMessage return false catch UnknownHostException e FeedbkArea setText UnknownHostException creating RtpMonitorManager n feedbkArea append e getMessage return false catch SessionManagerException e fFeedbkArea setText SessionManagerException creating RtpMonitorManager n feedbkArea append e getMessage return false catch IOException e feedbkArea setText IOException creating RtpMonitorManager n feedbkArea append e getMessage return false flgActive true creates a DisplayTask object to update the statistics on screen dispTask new DisplayTask this presInterval return true Updates the global statistics public void showGlobalStats GlobalReceptionStats stats mymgr getGlobalReceptionStats gText 0 setText new Integer stats getBytesRecd toString gText 1 setText new Integer stats getPacketsRecd toString gText 2 setText new Integer stats getRTCPRecd toString gText 3 setText new Integer stats getSRRecd toString 170
91. get the various session data as address port and ttl private void parseLocator String locatorString throws MalformedURLException String remainder getRemainder int colonIndex remainder indexOf int slashIndex remainder indexOf 2 160 gets the address if colonIndex 1 address remainder substring 2 colonIndex else throw new MalformedURLException RTP MediaLocator is Invalid Must be of form rtp addr port ttl tests if the address is valid try InetAddress Iaddr InetAddress getByName address catch UnknownHostException e throw new MalformedURLException Valid RTP Session Address must be given gets the port String portstr if slashIndex 1 portstr remainder substring colonIndex 1 remainder length else portstr remainder substring colonIndex 1 slashIndex tests if the port is an integer try Integer Iport Integer valueOf portstr port Iport intValue catch NumberFormatException e throw new MalformedURLException RIP MediaLocator Port must be a valid integer gets the ttl if slashIndex 1 String ttlstr remainder substring slashindex l remainder length try Integer Ittl Integer valueOf ttlstr ttl Ittl intValue catch NumberFormatException e Returns the RTP Session address retur
92. h two types of media e g audio and video E RTP CONTROL PROTOCOL RTCP RTCP provides back channel monitoring and synchronization for use with RTP streams RTCP provides a periodic transmission of control packets to all participants in the session RTCP performs the following functions e Feedback on the quality of the data distribution Receivers must periodically send RTCP packets containing a set of information related to the quality of each sender transmission such as the number of lost packets fraction of lost packets delay times and jitter variations in delay e Provides information about the participants in the session Each participant must periodically send their canonical name CNAME e mail address telephone number and so on The canonical name must be unique among the participants of a multimedia session a group of sessions The CNAME is sent together with the SSRC identifier allowing the detection of any collision in choosing the SSRC identifier in a session e Media synchronization RTCP conveys information about the absolute time wallclock for each participant If the senders are synchronized it will be possible to synchronize the different media in a session 22 a multicast poh err address port 1 RTP port 2 RTCP port 2 RTCP port 1 RTP audio port 1 RTP audio multicast port 2 RTCP audio address port 2 RTCP audio port 3 RTP video port 3 RTP video port 4
93. hanges meaningfully with respect to time It is also referred to as streaming media since it is delivered in a steady stream of packets that must be received and processed within a particular timeframe to produce acceptable results JMF 1 0 the 1998 version supports playback of several media types and RTP stream reception JMF 2 0 is being developed by Sun and IBM and is currently in public beta testing JMF 2 0 provides media capture functionality file saving and transmission of RTP streams together defining a plug in API that is intended to enable developers to customize and extend JMF functionality JMF 2 0 early access version was released in 37 June 1999 The beta version was released in August 1999 and the final release is being expected in Fall 99 This chapter was written based on JMF2 0 early access Sun 99 and the software development was performed using JMF 1 0 2 0 early access and 2 0 beta JMF ARCHITECTURE The JMF API can be divided into two parts A higher level API called the JMF Presentation and Processing API manages the capturing processing and presentation of time based media A low level API called the JMF Plug in API allows customization and extension Developers working on new capabilities are expected to add software elements to the JMF Plug in API thereby extending JMF functionality and supporting new media types JMF 2 0 uses the following basic classes interfaces to model the high level API e M
94. he Classpath and Extending the Java Classpath 4 Set the Filter to display the type of the Java files whose code you want to reverse engineer java or class files 5 Do one of the following to place the Java files of the type you selected into the Selected Files list In the File list box select one or more individual files and click Add e Click Add All e Click Add Recursive 6 Select one or more files in the Selected Files box or click Select All to confirm the list of files to reverse engineer 7 Click Reverse to create or update your model from the Java source you specified An error dialog displays if any errors occur during reverse engineering 8 Check the Rose Log for a listing of any errors that might have occurred The procedure above is described in the Rational Rose Help An additional requirement for reverse engineering of Java code is that the JDK API definitions must be available by adding the file c jdk1 2 2 jre lib rt jar to the classpath Using the reverse engineering feature Rational Rose will import from Java code all classes interfaces and associations but the diagrams are not automatically generated 78 APPENDIX B RTPMONITOR USER MANUAL rtpMonitor User Manual version 1 0 Contents Execution Defining a session Session Bookmarks Preferences Starting a session 6 Statistics Stopping a session Recording monitoring data Using the monitor without GUI 10 Wrong beha
95. iani ets 43 4 RTCP Repott aite etit ed 44 5 Eyent amp aic o diced ned aisha eut 46 RTP Media Locator RTP Session Address 47 7 RIP Session Managert 1 eerte nete eei t i teas 49 8 Receiving and Presenting RTP Media Streams 50 9 Transmitting RTP ee 51 10 ET PZSEaUSUDS Sos cono identidad dod 53 D SUMMARY E 54 INTRODUCTION ue M d DU ate 55 RTPMONITOR FUNCTIONALITY AND INTERFACE 55 1 Graphical User Interface GUD 55 2 Statistics DISDIQV a cie tou ti a Eu ERAN AT MEAN MER Ets 56 3 Statistics obere ghee 57 4 Media Presentation dte A de 57 5 Command Line Operation 57 viii C RTPMONITOR CLASS DESIGN 0000 58 1 RtpMonitorManager and 040444222 12 58 2 Record Task and PileC ataloe ete 60 3 RtpPlayer WindOW e abe ee 61 4 RtpMonitor ia ceci t er REIR RE GG PERSE RR EGO ASA REL NER Se 63 5 RtpMonitor Applet s eiue bas die eolit 63 6 1 63 D SUMMARY fece 64 MANAGEMENT INFORMATION BASE MIB
96. ide access to IGMP Deering 89 packets on the network layer and would otherwise require additional programming of native code e g C source code via the Java Native Interface JNI Sun 99 to achieve RTCP capabilities B RECOMMENDATIONS FOR FUTURE WORK A number of excellent opportunities for future work are now possible 1 Participants Information RTCP Session Description Reports convey several data about each participant as name e mail and tool being used This information can be added to RTPMonitor for presentation and recording purposes JMF contains the necessary classes and methods to set send and retrieve this data 73 2 Extensible Markup Language XML Recording rtpMonitor records the RTP session data as text files The use of Extensible Markup Language XML Word Wide Web Consortium 99 for recording the data would allow an easier data retrieval Java based XML parsers are available and can provide an efficient way to read and write Java data structures as XML documents and vice versa 3 Recorded Data Analysis and Presentation A tool to retrieve remotely or receive the rtpMonitor output file statistics is needed It should be able to present the each individual data in a graphical format covering a period of time defined by the user Again XML provides browsing options for automatic presentation of such data by any web browser 4 Session Description Protocol SDP Reception The Session Descriptio
97. intervalText intervalPresLabel new Label Presentation Interval 152 intervalPresLabel setBounds 10 150 140 25 add intervalPresLabel Bi ntervalPresText new TextField 5 intervalPresText setBounds 160 150 40 25 add intervalPresText ndLabel new Label Monitoring Period endLabel setBounds 10 180 100 25 endLabel endChoice new Choice endChoice setBounds 120 180 80 25 add endChoice for int 11 0 ii lt strEndsIn length 11 endChoice add strEndsIn ii endChoice select 0 view abel new Label External viewer viewerLabel setBounds 10 210 120 25 viewerLabel viewerText new TextField c Program Files accessories wordpad exe viewerText setBounds 20 240 230 20 viewerText setFont new Font null Font PLAIN 10 viewerText loadPreferences Enables the GUI input elements public void enableInput recordBox setEnabled true partBox setEnabled true playBox setEnabled true intervalText setEnabled true intervalPresText setEnabled true endChoice setEnabled true viewerText setEnabled true Disables the GUI input elements public void disableInput recordBox setEnabled false partBox setEnabled false playBox setEnabled false intervalTe
98. ion 1 0 versionLabel setBounds 20 30 150 25 add versionLabel Label versionDateLabel new Label Version date 30 August 1999 versionDateLabel setBounds 20 60 180 25 add versionDateLabel Label npsLabel new Label Naval Postgraduate School npsLabel setBounds 20 90 150 25 npsLabel Label vrtpLabel new Label virtual reality transfer protocol vrtp vrtpLabel setBounds 20 120 200 25 vrtpLabel Label siteLabel new Label http www web3d org WorkingGroups vrtp siteLabel setBounds 20 150 240 25 add siteLabel end of class About 137 package org web3d vrtp rtp import java awt import java awt event import java util import java io The Dialog to add a session bookmark lt P gt author Francisco Afonso afonso cs nps navy mil version 1 0 public class AddBookmark extends Dialog implements ActionListener Vector sessionAddressVec sessionNamesVec Label sessionAddLabel sessionAddRealLabel sessionNameLabel TextField sessionNameText Button addButton cancelButton RtpMonitor theParent Constructor lt P gt param parent the parent frame public AddBookmark Frame parent super parent Add Bookmark true setSize 350 170 setLayout null setBackground Color lightGray addWindowListener new Close
99. ion Bookmarks As an option to writing the session address it is possible to select a session bookmark The program already comes with some pre defined session bookmarks Bookmarks can be added and deleted RtpMonitor File Preferences Help Total Bytes Total Packets RTCP Packets SR Packets Bad RTP Packets Bad RTCP Packets SR Packets 7 BadRRPackets 7 Active Participants Global Statistics Bad SDES Packets Bad BYE Packets Local Collisions Remote Collisions 7 Looped Packets Failed Transmission Unknown Type Passive Participants 81 Session Name Stream Username Lost PDUs Processed PDUs MisOrdered PDUs 1 IvalidPDUs Duplicate PDUs 1 Feedback Reports Fraction Lost Jitter Packets Last The option Select displays a window with the pre defined session bookmarks Click over the desised session to select it Select Bookmark The option Add allows the insertion of a new session bookmark This option is enabled only when a session has been started The session address is the session of the current session The session name will be the bookmark name Add Bookmark 82 The option delete allows the deletion of a bookmark A window with the existing bookmarks will be presented and the user can select the bookmark to be deleted and click the Delete
100. kup Language XML target set definitions Vi JNTERODUC ION ite RARE oe Nh Rh RR 1 A BACKGROUNDS dent dene 1 B MOTIVATION Sese Strona hs 1 C OBTEGOTEVESt 2 D ORGAN eite beide e 3 Ie RELATED WORK vids Cae baa Calica cabo ten eua e VE 5 A INTRODUCTION seeds 5 B RTP MONITORING IN MEDIA CONFERENCE APPLICATIONS 5 1 Video Conferencing Tool 5 25 Robust Audio Tool 7 C DEDICATED MONITORS ane aos dpi t paras 8 1 8 2 Session Directory SDR 8 3 RMON 9 4 caddie tds teal dst 11 5 M5 n 12 D ouisoses iuis uoles 13 E INTERNET 2 SUR VEY Oo dtes esas pari e 15 F DESIGN PATTERNS oneone Gath o eid 15 REAL TIME TRANSPORT PROTOCOL RTP sse 17 A INTRODUCTION esee b e eben 17 B OVERVIEW OF TRANSPORT RELATIONSHIPS 17 dU 18 1 RTP Units Mixer Translator and Monitor
101. le false Loads the session bookmarks from file bookmarks txt private void loadBookmarks sessionAddressVec new Vector sessionNamesVec new Vector try BufferedReader input new BufferedReader new FileReader bookmarks txt String line while line input readLine null int pos line lastIndexOf rtp if pos 1 sessionAddressVec addElement line substring pos trim sessionNamesVec addElement line substring 0 pos trim 139 input close catch FileNotFoundException e System out println Add Bookmarks getMessage catch IOException e System err println Exception reading bookmark getMessage Saves the session bookmarks to file bookmarks txt XA private void saveBookmarks PrintStream output try output new PrintStream new FileOutputStream bookmarks txt false for int 11 0 ii lt sessionAddressVec size 11 output print String sessionNamesVec elementAt ii output print output println String sessionAddressVec elementAt ii output close catch FileNotFoundException e System out println Saving bookmarks 4 getMessage catch IOException System err println Exception writing bookmark getMessage end of class AddBookmark 140 pack
102. lesMenu addSeparator filesMenu add exitItem helpMenu new Menu Help aboutItem new MenuItem About aboutItem addActionListener this helpMenu add aboutItem bar new MenuBar bar add filesMenu bar add bookmarkMenu bar add preferences bar add helpMenu setMenuBar bar modPrefDialog new ModifyPreferences this sessionLabel new Label Session Address sessionLabel setBounds 10 60 100 25 add sessionLabel sessionText new TextField rtp sessionText setBounds 110 60 230 25 add sessionText sessionNameLabel new Label Session Name sessionNameLabel setBounds 360 60 90 25 add sessionNameLabel sessionNam xt new TextField sessionNameText setBounds 450 60 180 25 add sessionNameText start new Button Start start setBounds 660 60 40 25 start addActionListener this start setEnabled true add start 165 stop new Button Stop stop setBounds 720 60 40 25 stop addActionListener this stop setEnabled false stop globalStatLabel new Label Global Statistics globalStatLabel setBounds 160 100 100 20 add globalStatLabel gLab new Label 15 gText new TextField 15 int offsetx 0 int offsety 0 for int 11 0 11 lt 15 iitt if ii 8
103. modPrefDial modPrefDial modPrefDial e getSource selBmDial selBmDial selBmDial og og setVisible true og og og og viewPref SetTitle View Preferences disableInput SetVisible true selectBm new SelectBookmark this null e getSource deleteBm delBmDialog new DeleteBookmark this delBmDialog setVisible true delBmDialog null e getSource addBm addBmDialog new AddBookmark this addBmDialog setVisible true addBmDialog null e getSource last5Item runViewer sessionText getText LastFiveMinutes txt e getSource previous5SItem runViewer sessionText getText PreviousFiveMinutes txt e getSource lastHourlItem runViewer sessionText getText LastHour txt e getSource previousHourltem runViewer sessionText getText PreviousHour txt e getSource headerItem runViewer sessionText getText Header txt e getSource aboutItem aboutDialog new About this aboutDialog setVisible true aboutDialog null e getSource exitItem System exit 0 169 starts the monitoring session by creating a RtpMonitorManager object private boolean startSession tries to create the RtpMonitorManager object try monMgr new RtpMonitorManager locator flgPart fl
104. n Protocol SDP is intended for describing multimedia sessions for the purposes of session announcement session invitation and other forms of multimedia session IETF 98 In rtpMonitor the user has to enter the RTP session address Future work needs to add SDP reception capability to simplify starting a monitoring session and allowing the detection of ongoing sessions in addition to the current approach 5 RtpMonitor Activation from SDR Session Directory SDR is a session directory tool designed to allow the advertisement and joining of multicast conferences on the MBone UCL 99 It is 74 possible to launch external application from SDR by modifying some of the SDR configuration files Providing a plug in file to SDR might result in an easier activation of the rtpMonitor application 6 JMF Extensibility for Other Media Java Media Framework distribution comes with a set of concrete classes to implement the RTP transmission reception and playback of audio and video However the extension of JMF to support other types of media is highly desirable An important area of future work is the implementation of simulation data transmission and reception using the RTP API of Java Media Framework This work will have direct application in the vrtp streaming behaviors stack 7 Automated Network Monitoring of RTP Streams for The rtpMonitor class library can be integrated with the vrtp protocol to allow the autom
105. n RTP Issues and Options for RTP Multiplexing Conformance Texts for RTP Scalability Algorithms RTP Testing Strategies I SUMMARY The Real Time Transport Protocol RTP provides a way to transmit time based media over wide area networks WAN adding synchronization and feedback features over the existing transport protocol Although RTP was initially devised for application in audio and video conferences this protocol can be applied to convey other types of streamed media across the network 35 THIS PAGE LEFT INTENTIONALLY BLANK 36 IV JAVA MEDIA FRAMEWORK JMF A INTRODUCTION This chapter provides an overview of the Java Media Framework JMF basic architecture and the specialized set of classes to manage RTP transmission reception and control Several Unified Modeling Language UML Booch et al 97 diagrams are used to illustrate JMF classes interdependencies and behavior The software application Rational Rose 981 Rational 99 was used to import the class components from the JMF API and to draw these diagrams Appendix A contains a description of how UML diagrams be prepared using the software Rational Rose 981 B OVERVIEW Java Media Framework JMF is a Java Application Programming Interface API developed by Sun Microsystems in partnership with other companies to allow Java programs deal with time based media especially audio and video Sun 99 Time based media can be defined as any data that c
106. n String form of the RTPSession address public String getSessionAddress return address 161 Returns return public int return Returns return public int return the RTP session port RTP session port getSessionPort port the session Time to live time to live TTL getTTL ttl end of class RtpMediaLocator 162 lt P gt package org web3d vrtp rtp import javax media rtp import javax media rtp event import javax media rtp rtcp import java awt import java awt event import java net import java io import java util The RtpMonitor Application p This class is a frame that implements the RtpMonitor GUI If any command line argument is passed the RtpMonitorCommandLine class is called instead author Francisco Afonso afonso8cs nps navy mil version 1 0 public class RtpMonitor extends Frame implements ActionListener ItemListener TextField sessionText TextArea activeArea passiveArea f Choice streamChoice Button start stop changeStream sessionNameText dbkArea abel sessionLabel sessionNameLabel streamLabel feedbkLabel abel endLabel abel globalStatLabel activeLabel passiveLabel feedbkFieldsLabel abel TextField gText String gField Total Bytes
107. nd assist a network administrator in managing the traffic on an Intranet The client main window displays the total bandwidth occupied by the multicast traffic and gives a graphical breakdown of the traffic by application type as shown in Figure 2 4 MultiMON Multicast Monitor File Options Help Multicast types on localhost 10 current 416 1 kb s v 28 wv 84K 128 256 512K 2048 10000 zz Figure 2 4 Multi MON client window Robinson et al 96 11 The software includes an RTCP monitoring and recording tool MERCInari that allows an analysis of the RTCP data for QoS management A session can be recorded for later analysis Multi MON is written in tk tcl but needs tcpdump xplot the distributed processing additions and the object oriented additions to tk tcl It runs in Sun workstations but it can be ported to other platforms including Windows 95 98 and NT 5 MHealth MHealth the Multicast Health Monitor is a graphical multicast monitoring tool Makofske et al 99 By using a combination of application level protocol data for participant information and a multicast route tracing tool for topology information MHealth is able to present a multicast tree s topology and information about the quality of received data Figure 2 5 contains a screenshot of MHealth MHealth also provides data logging functionality for the purpose of isolating and analyzing network faults Logs
108. ners RTPSessionListener RTPSendStreamListener RTPReceiveStreamListener and RTPRemoteListener These listeners provide a mechanism of event notification on the state of the RTP session and its streams The RTPSessionListener interface detects events related to the RTP session as a whole rather than a particular stream or participant Two types of events can be posted NewparticipantEvent generated when a RTCP packet from an unknown participant was received and LocalCollisionEvent generated when a SSRC collision was detected between the local participant and a remote one The RTPSendStreamListener interface detects state transitions that occur on a RTPSendStream Four types of events can be posted NewSendStreamEvent generated when a new transmitting stream has been created ActiveSendStreamEvent generated when the transfer of data from the DataSource object has started arriving after a previous stop nactiveSendStreamEvent generated when the transfer of data from the DataSource object has stopped e SendPayloadChangeEvent generated when the payload type of the DataSource object has changed The RTPRecvStreamListener interface detects state transitions that occur on a RTPRecvStream Seven types of events can be posted e NewRecvStreamEvent generated when a new incoming stream has been detected This means that RTP data packets has been received from a SSRC that had not previously been sending data 46
109. netAddress getByName session address fails sending RTCP packets false otherwise lt P gt param willPlayStreams true if the Monitor will play the receiving streams false otherwise lt P gt param willRecord true if the Monitor will record statistical i data about the session false otherwise lt P gt Qparam recordInterval the time between data recordings in seconds exception MalformedURLException if the locatorString argument does not conform to the syntax p exception UnknownHostException P 181 exception SessionManagerException Exception thrown when there is an error starting an RTPSessionManager exception IOException Exception thrown when there is an error in RTPSessionManager p public RtpMonitorManager String locatorString boolean willParticipate boolean willPlayStreams boolean willRecord double recordInterval throws MalformedURLException UnknownHostException SessionManagerException IOException flgPart willParticipate flgPlay willPlayStreams flgRecord willRecord creates the RtpMediaLocator object rtpml new RtpMediaLocator locatorString creates an empty RtpSessionManager object mgr new RTPSessionMgr if the user select to play the streams registers as a listener for received streams if flgPlay mgr addR
110. nitorCommandLine 180 package org web3d vrtp im im im por por por im im im im im im RT por por por por por por PSessionMgr class java io java net java util javax media er er cT javax media rtp javax media rtp javax media rtp rtp event com sun media rtp javax media protocol F public class RtpMonitorManager implements Receiv A class that encapsulates all operations necessary to start a new monitoring session play its streams and record statistical data lt P gt This class does not display statistics on screen That must be done by another class usually a frame using data from a SessionManager object see method getSessionManager author Francisco Afonso version 1 0 afonso cs nps navy mil StreamListener priva m priva priva priva priva priva priva priva RtpMediaLocator rtpml null SessionManager mgr null SessionAddress sessaddr boolean flgPart boolean flgPlay boolean flgRecord Hashtable windowlist RecordTask recTask null param locatorString the session description string format e g rtp 224 2 134 67 50980 127 lt P gt param willParticipate true if the Monito r will participate in the session if I
111. nterval seconds System out println monitoring duration endsInHours hours Method that will create the RtpMonitorManager object and will exit the program when the user defined duration is elapsed public void run tries to create the RtpMonitorManager object try monMgr new RtpMonitorManager locator willpart willplay willrecord interval catch MalformedURLException e System err printlin MalformedRTPMRLException creating RTPMonitorManager System err println e getMessage System exit 0 catch UnknownHostException e System err printlin UnknownHostException creating RTPMonitorManager System err println e getMessage System exit 0 catch SessionManagerException e System err println RTPSessionManagerException creating RTPMonitorManager System err println e getMessage 179 System exit 0 catch IOException System err println IOException creating RTPMonitorManager System err println e getMessage System exit 0 runs until the user aborts the program ctrl C or the monitoring period is over while true tests if the monitoring period is over if endDate compareTo new Date lt 0 System exit 0 try Thread sleep 50000 catch InterruptedException e end of class RtpMo
112. o windows could not be closed e After a session had been stopped and a new session had been initiated the global statistics about the previous session were still being considered In JMF 2 0 Early Access and JMF 2 0 Beta the only observed error is related to the Cumulative Number of Packets Lost Packets Lost in the Feedback Area which returns wrong values after some time This problem has been reported to Sun s JMF bugs e mail box jmf bugs sun com and to Sun s JMF interest mailing list jmf interest java sun com D EXTENDING DIS JAVA VRML PDU HEADER Protocol Data Units PDU currenty used by the vrtp protocol Brutzman 99 are based on the Distributed Interactive Simulation IEEE 95 standard As the vrtp protocol intends to use the Real Time Transport Protocol as the transport protocol an RTP Header should be added to the existing DIS PDU Although such a modification is no longer strictly compliant with DIS over the wire formats it nevertheless provides and interesting opportunity for research and testing 70 As a product of this thesis a new Java class for extending the DIS PDU with RTP header information was created This class is specifically designed to be part of the DIS package mil nps navy dis used by the DIS Java VRML application a component of the vrtp protocol Brutzman 99 This class was named RtpHeader Appendix F contains the RtpHeader Javadoc and Appendix G contains the RtpHeader source code
113. omponents and Interface Components e Component View contains the Component Diagrams Deployment View contains a Deployment Diagram To create a new diagram the user has to select the branch he wants the diagram in click with the mouse right button and select what type of diagram is to be created A new blank diagram is shown and the components can be created and placed on the diagram by selecting the appropriate component in a tool bar and clicking in the place the component must be positioned in the diagram Depending on the type of the component different information should be provided By right clicking on a component a pull down menu is shown and the user can invoke the component specification as long as the option setting feature Reverse Engineering of Java Source Code Reverse engineering is the process of creating or updating a model by analyzing Java source code As Rational Rose reverse engineers each java or class file it finds the classes and objects in the file and includes them in the model 77 To reverse engineer all or part of a Java application 1 If you are updating an existing model open the model otherwise create a new model 2 On the Tools menu point to Java and then click Reverse Engineer 3 From the directory structure select the classpath setting and folder where the files you re reverse engineering are located If the list is empty check your classpath For details see How Rose J Models t
114. one week default 1 hour e External viewer textbox defines an external text editor that will be called to present the output files generated by the monitor default MS Windows Wordpad The selected preferences will be saved on file and will be available in the next time the program is executed 5 Starting a session After entering the session address and the desired option the user can click on the start button to start a monitoring session If the supplied session address is invalid or if any other problem in establishing a session occurs an error message will be displayed in the feedback text area 6 Statistics The program displays the following types of information about the session Global statistics general information about the whole session e Active Participants the username of the participants actually sending data streams e Passive Participants the username of the participants that do not send any stream e Stream the stream that is currently being monitored That stream can be changed in a session with multiple incoming streams by clicking in the change button and selecting another stream in the stream selection box Feedback that display area presents the RTCP feedback data related to the selected stream Usually the participants in the session send feedback data about all streams 84 7 Stopping a session Clicking the stop button can stop a session After stopping a session the user is allow
115. ons data via the command line The format is java org web3d vrtp rtp RtpMonitor sessionAddress options The options are part the monitor participates in the session sends RTCP packets as a receiver in the session play the monitor play streams record the monitor records statistics i nnn nnn defines the recording interval in seconds default 30s e ppp ppp defines the monitoring duration in hours default 168 hours 1 week help displays the options on the console Example java org web3d vrtp rtp RtpMonitor rtp 224 120 67 46 64542 127 play record e 24 Action runs the program for monitoring the session in the IP address 224 120 67 46 port 64542 with TTL 127 It does not participate in the session but plays the incoming streams and records statistics on files The recording interval will be 30 seconds and the monitoring duration will be 24 hours To stop the program press lt Ctrl C gt 10 Wrong behaviors and results bugs Several early bugs were related to JMF1 1 and were corrected in JMF2 0 Early Access new bug was observed in JMF 2 0 Early Access the Cumulative Number of Packets Lost Packets Lost in the Feedback Area is returning wrong values after some time This problem was reported to Sun s JMF bugs list in 08 Jun 1999 but it is still present in JMF2 0 Beta 88 11 Running the program in other directory To run the program in another directory copy the files bookmarks txt
116. ormation about the session address and other settings used in a session like TTL and SSRC The format is similar to an URL The RTP MediaLocator string is of the form rtp address port SSRC content type TTL 47 Optional parameters are enclosed in brackets Address is the IP address of the session Port is the port number used for RTP packets It must be an even number according RFC1889 SSRC is optional Content type can be either audio or video TTL is the time to live also optional The string above is used to create a RTPMediaLocator object If the media locator is invalid a MalformedRTPMRLException will be thrown The class RTPMediaLocator has several methods to retrieve the above information about a session For example the method getSessionAddress returns a string with the IP address and the method getSessionPort returns an integer with the RTP port number However to create a session and instantiate a RTPSessionManager under JMF another object has to be created first an RTPSessionAddress RTPSessionAddress is a class that encapsulates a pair of multicast addresses each constituting of an IP address and a port number One multicast address is used by RTP and the other by RTCP In fact this definition of a RTPSessionAddress is too broad because RFC1889 says that the RTCP multicast address must have the same IP address and a immediately higher port with relation the RTP address Also RTP port must be even by RFC
117. orrectSSRC stream getSSRC A public void showFeedbacks Updates the stream feedbacks if flgUpdateStreams return Participant part Vector reports feedbacks Report rep Feedback feedbk feedbkArea setText Vector aux for int ii part reports ii lt aux size part getReports for int 33 0 11 lt repor rep Report repor feedbacks for int kk 0 feedbk Feedback if feedbk getSSRC feedbkArea app RtpUtil getU double fraction dbkArea app fillBlanks dbkArea app fillBlanks S dbkArea app fillBlanks ts size ts elementAt jj rep getFeedbackReports kk feedbacks size mymgr getAllParticipants 1 Participant aux elementAt 0 Ttjg kk feedbacks elementAt kk SSRCtoShow nd fillBlanks sernameOrCNAME part 19 ee feedbk getFractionLost 256 0 String valueOf fraction nd tring valueOf f nd String valueOf f font 6 dbk getJitter 8 dbk getNumLost 10 173 Take action when selection boxes are used public void itemStateChanged ItemEvent ie if ie getSource streamChoice SSRCtoShow Long streamTable get i flgUpdateStreams true changeStream setEnabled true streamChoice setEnabled false
118. ot be implemented using JMF e Detect what JMF statistics are not part of RTP MIB Some of the JMF statistics can be added to the RTP MIB 66 The comparison was sent to the JMF and IEFT AVT mailing lists The comments made by Bill Strahm one of the authors of the RTP MIB Internet Draft are included in the table of Appendix E Sun Microsystems software engineers have not replied with any comments E SUMMARY The Real time Transport Protocol RTP Management Information Base MIB consists of a new Internet Draft proposed by the AVT group of the IETF to be applied in RTP network management with SNMP A number of significant differences were found between JMF 2 0 Sun 99 and the RTP MIB Baugher et al 99 Further work will need to be performed by one or both organizations to resolve these discrepancies 67 THIS PAGE LEFT INTENTIONALLY BLANK 68 EXPERIMENTAL RESULTS A INTRODUCTION This chapter presents the experimental results achieved with the rtpMonitor application and describes problems faced during the testing phase Furthermore this chapter presents the work on an RTP header for the Distributed Interactive Simulation DIS protocol IEEE 95 B TEST RESULTS The Java application rtpMonitor described in Chapter V was tested using the versions 1 1 7 1 2 1 and 1 2 2 of the Java Development Kit JDK in combination with versions 1 0 2 0 Early Access and 2 0 Beta of the Java Media Framework JMF Bet
119. ot provided by JMF payload type from the RTP Header SenderStartTime TimeStamp the value of Not implemented It is the time when the Monitor detected SysUpTime at the time this row was created this source It can be derived by the JMF application 196 Not provided by MIB Not provided by MIB Not provided by MIB Not provided by MIB RevrTable LostPDU int the difference between the number of packets expected as determined by the RTP sequence number range and the count of packets actually received and validated MisorderedPDU int the total number of data packets that came in out of order as per the RTP sequence number InvalidPDU int the total number of RTP data packets that have failed to be within an acceptable sequence number range for an established SSRC id DuplicatePDU int the total number of RTP data packets that match the sequence number of another already in the input queue Desirable Bill Strahm comments RcvrLostPackets in the Receiver Table Desirable Bill Strahm comments Not available in the MIB It would have to be in the RcvrTable Desirable Bill Strahm comments Not available in the MIB It would have to be in the RcvrTable Desirable Bill Strahm comments Not available in the MIB It would have to be in the RcvrTable RTP MIB JMF based RTP Monitor Application RcvrSRCSSRC Unsigned32 the SSRC of RcevrSRCSSRC long the sender
120. our data files p param pref a string containing the directory where the data must be written public FileCatalog String pref prefix pref creates File objects mind new File prefix LastFiveMinutes txt min5last new File prefix PreviousFiveMinutes txt hour new File prefix LastHour txt hourlast new File prefix PreviousHour txt header new File prefix Header txt retrieves the date of last record for this session String lastDateRef retrieveDateRef copies the header file to the session directory if it does not exit if header exists concatenate prefix Header txt Header txt 147 if min5 exists if there is a last five minutes file transfers its contents to the last hour file and deletes the last five minutes file if lastDateRef null concatenate prefix LastHour txt prefix LastFiveMinutes txt min5 delete deletes the previous five minutes file if it exists if mindlast exists min5last delete if hour exists if there is a last hour transfers its contents to the related date file file and deletes the last hour file if lastDateRef null String dateFileName new String prefix Date lastDateReft txt concatenate dateFileName prefix LastHour t
121. pound RTCP packet Each participant must send RTCP compound packets with at least one SR or RR and one SDES with his CNAME 1 Sender Report SR A Sender Report is issued if the participant has sent any RTP data packets since the last report otherwise a Receiver Report RR is issued A sender report besides having statistical information about itself may contain reception statistics of a maximum 24 of 31 other senders If a sender has more than 31 receiver statistics to send then it must add a RR to the compound packet The format of the Sender Report is shown in Figure 3 4 The Sender Report packet consists of three sections a header section a sender information section and a receiver information section A fourth profile specific extension section can be defined The fields have the following meaning e Version V 2 bits Identifies the version of RTP The version defined in RFC1889 is two 2 0 3 8 16 31 V P RC PT 200 SR length SSRC of sender NTP timestamp most significant word NTP timestamp least significant word RTP timestamp sender s packet count sender s byte count SSRR 1 SSRC of the first source fraction cumulative number of packets loss loss extended highest sequence number received interarrival jitter last SR LSR delay since last SR DLSR SSRR 2 SSRC of the first source profile specific extensions
122. r this add sessionNamesList 189 Activated when a bookmark choice is made lt P gt param parent the parent frame public void itemStateChanged ItemEvent e int index sessionNamesList getSelectedIndex theParent sessionText setText String sessionAddressVec elementAt index theParent sessionNameText setText sessionNamesList getItem index setVisible false Loads the session bookmarks from file bookmarks txt hf private void loadBookmarks sessionAddressVec new Vector try BufferedReader input new BufferedReader new FileReader bookmarks txt String line while line input readLine null int pos line lastIndexOf rtp if pos 1 sessionAddressVec addElement line substring pos sessionNamesList add line substring 0 pos input close catch FileNotFoundException e System out println Select Bookmark 4 getMessage catch IOException e System err println Exception reading bookmark 4 getMessage end of class SelectBookmark 190 APPENDIX E COMPARISON RTP MIB VERSUS JMF STATISTICS 191 SessionTable RTP MIB JMF based RTP Monitor Application SessionIndex Integer32 an index of the conceptual row which is for SNMP purposes only and has no relation with any protocol value SessionDomain TDomain the
123. r object in JMF Figure 5 3 shows a UML sequence diagram representing the steps taken by RtpMonitorManager in creating and initializing the session manager Figure 5 4 shows a class diagram of the classes related to RtpMonitorManager RtpUtil is a class that has only static methods for performing some extra functionality to JMF For example there is a method to return the username given a RTPParticipant object 2 RecordTask and FileCatalog RecordTask is a class used by RtpMonitorManager objects to write the statistics periodically to disk It is created as a separate thread that waits for a fixed period of time after writing data to disk This class writes data to the file called statisticsLastReport txt that contains the last single report only The FileCatalog class is actually responsible for transferring data to other files as well last five minutes last hour and so on 60 RtpMonitorManager RtpMediaLocator InetAddress RtpSessionAddress RTPSessionMgr address getSessionAddress port getSessionPort destaddr getByName address sessaddr create destaddr port destaddr port 1 start sessaddr t 2 Figure 5 3 RTPSessionManager Initialization UML Sequence Diagram 3 RtpPlayerWindow RtpPlayerWindow is a class used to create a window for playing an audio video stream It is a subclass of PlayerWindow adding the capacity of modifying the window name Both cl
124. ronization source identifier SenderCNAME DisplayString the SenderCNAME String canonical name of the sender SenderAddress Taddress the unicast Not provide by JMF i transport source address of the sender SenderPackets Counter64 count of RTP SenderPackets int Called ProcessedPDU by JMF number of packets sent by this sender or observed by an valid packets received from the selected RTP Monitor since SenderStartTime source Possible type issue It can overflow SenderOctets Counter64 count of RTP Not provided by JMF JMF only has a corresponding session count octets sent by this sender or observed by an RTP Monitor since SenderStartTime SenderTool DisplayString Name of the Not implemented It can be read from JMF application program source of the stream RTPSourceDescription object SRs Counter32 a counter of the number of Not implemented Not part of native JMF statistics It can be RTCP Sender Reports that have been sent derived in an JMF application by from this sender or observed if the RTP entity monitoring RecvSenderReportEvents is a monitor since SenderStartTime SenderSRTime TimeStamp the value of Not implemented It can be read from JMF RTPSenderReport SysUpTime at the time that the last SR was object received from this sender in the case of a monitor or receiving host or sent by this sender in case of a sending host SenderPT integer 0 127 static or dynamic N
125. s to recurring problems that occur during software development In 1995 the book Design Patterns Gamma 95 has started popularizing the idea of patterns In recent years new patterns have been proposed and several books about patterns have been released Frequently books about Design Patterns give examples of pattern implementations in some computer language A good book for studying patterns in Java was written by Mark Grand Grand 98 Sun Microsystems Java Application Programming Interfaces APIs contain plenty of examples of pattern 15 use Design patterns provided great benefit during the software analysis design and implementation work in this thesis 16 REAL TIME TRANSPORT PROTOCOL RTP A INTRODUCTION This chapter presents the Real time Transport Protocol RTP functionality and packet format RTP is a header format and control protocol designed to support applications transmitting real time data such as audio video or simulation data over multicast or unicast network services RTP was proposed by RFC1889 Schulzrinne et al 99 and has received wide acceptance B OVERVIEW OF TRANSPORT RELATIONSHIPS The transport layer provides a flow of data between hosts In the TCP IP protocol suite there are two vastly different transport protocols the Transmission Control Protocol TCP and the User Datagram Protocol UDP While TCP provides a reliable flow of data between two hosts by using packet ackno
126. session Appendix C contains the rtpMonitor Javadoc and Appendix D contains the rtpMonitor source code RtpMonitorManager RtpUtil The RtpMonitorManager class is the main interface between a user application and JMF It performs the following functions e Creates and starts a session represented by a RTPSessionManager object in JMF e Records session statistics in files e Presents i e plays incoming media streams 58 RtpMonitor DOS UNIX prompt RtpMonitorCL RtpMonitor Manager and RtpUtil RecordTask RtpPlayer and Window FileCatalog _ Audio or Video Figure 5 2 RTPMonitor Data Flow Diagram RtpMonitorManager does not have methods to retrieve each single statistic in an RTP session If an application needs access to individual statistics e g for display purposes it is necessary to retrieve the RTPSessionManager object and use its methods to get the desired set of statistics 59 The following parameters are necessary for instantiating new RtpMonitorManager object e The session address string e g rtp 224 2 134 67 50980 127 e A Boolean variable indicating if the statistics are to be recorded on files e A Boolean variable indicating if the incoming streams are to be played e A Boolean variable indicating if the monitor will actively participate in the session i e send RTCP packets During instantiation RtpMonitorManager creates a RTPSessionManage
127. should be increased by 160 each 20 ms The timestamp initial value should be random e SSRC 22 bits This field identifies the synchronization source It is a number chosen randomly It must be unique among all participants in a session There is a mechanism to solve conflicts when two sources choose the same number described in Session 8 of RFC1889 A participant need not use the same SSRC identifier in all sessions of a multimedia session e CSRC list 0 to 15 items 32 bits each The CSRC list identifies the contributing sources for the payload contained in this packet It is used only by mixers which combine several streams from different sources in a single stream 3 Profiles and RTP Header Extension The RTP protocol is designed to be malleable and to allow modifications and additions as defined by the corresponding media profile specification Typically each application only operates under one profile For example RFC1890 Schulzrinne et al 99 defines a profile for audio and video conferences 20 In the RTP fixed header the marker bit M and the payload type PT fields carry profile specific information If the marker bit is set a header extension will be added to the RTP fixed header to provide the additional data functionality required for the profile The header extension has the following format seen in Figure 3 2 0 16 31 defined by the profile Length of 32 bit words header extension data
128. st send a BYE packet listing its SSRC and the CSRC of all sources it handles The last section is optional It gives a reason by leaving a section like bad reception or time for lunch The length and reason for leaving fields have the same behavior as length and context fields of the SDES item 32 F MULTIMEDIA IN RTP Each media must be carried in a distinct RTP session Interleaving packets with different RTP media types but using the same session and SSRC is not permitted in order to avoid the following problems An SSRC has only one single timing and sequence number Different payload types would require distinct timing spaces Also there would be no means to identify which media suffered losses The RTCP sender and receiver reports can only describe one timing and sequence number space per SSRC and do not carry a payload type field An RTP mixer would not be able to combine interleaved streams of incompatible media onto one stream It would not be possible to use different network paths or resource allocations for each media ANALYSIS OF SR AND RR REPORTS It is expected that reception quality feedback data will be useful not only for the senders but also for receivers and third part monitors The senders can modify its transmission based of the feedback receivers can determine where the problems are local regional or global network managers may use profile independent monitors that
129. static void main String args int nArgs args length if args length 0 RtpMonitor myProg new RtpMonitor else RtpMonitorCommandLine myProg new RtpMonitorCommandLine args myProg run end of class RtpMonitor 176 package org web3d vrtp rtp line inputs import javax media rtp import javax media rtp event import javax media rtp rtcp import java io import java net import java util A class used to start a RTP monitor from command p This monitor does not have the option of playing streams author Francisco Afonso afonso8cs nps navy mil version 1 0 public class RtpMonitorCommandLine boolean willpart false boolean willplay false boolean willrecord false String locator null double interval 30 0 int endsInHours 168 Date endDate RtpMonitorManager monMgr Method called upon executing class RtpMonitorCommandLine XA public static void main String args RtpMonitorCommandLine myProg new RtpMonitorCommandLine args myProg run variables flags lt P gt part monitor sends RTCP packets lt P gt play monitor play streams lt P gt record monitor records statistics lt P gt hs P ox F Xo X Xo F 177 Constructor It reads the command line arguments and sets The comman
130. stream and RR if the participant is passive If the participant sends more than one stream this method will return the same number of SR reports because each SR report is associated to one stream SSRC RTCPReport has a method called getFeedback that returns a vector of RTCPFeedback objects Each RTCPFeedback object conveys information about the 44 reception of one incoming stream In other words it represents a feedback from a SSRC about other SSRC that originates a stream Feedback information includes fraction lost cumulative number of packets lost etc Figure 4 3 contains a class diagram describing the relationship between RTPParticipant and other classes interfaces discussed so far This class diagram uses the standard notation specified for the Unified Modeling Language UML Booch et al 97 Interface RTPParticipant Interface getStreams Vector RTPStream getSourceDescription Vector 1 getReports Vector N P4 1 1 Interface Interface RTPRecvStream RTPSendStream generates Interface RTCPReport getFeedbacks Vector contains p 1 M Interface RTCPFeedback Interface Interface RTCPReceiverReport RTCPSenderReport Figure 4 3 RTPParticipant Class Diagram 45 5 Event Listeners The RTP API has four types of event liste
131. tamp LSR 32 bits The middle 32 bits out of 64 bits in the NTP timestamp received as part of the most recent RTCP SR packet from the source SSCR n e Delay since last SR DLSR 32 bits The delay expressed in units of 1 65536 seconds between receiving the last SR packet from source SSRC n and sending this reception report block Based on this information and the LSR the sender can compute the round trip propagation delay to this receiver This can be done by the following formula Round Trip A LSR DLSR where A is the time the receiver gets the RR message Figure 3 5 is a time diagram that represents the DLSR 2 Receiver Report RR The format of the Receiver Report RR is the same of the Sender Report SR except that the packet type field contains the value 201 and that there is no sender information section An empty RR packet RC 0 must be put at the head of a compound packet when there is no data transmission or reception to report Figure 3 6 shows the Receiver Report packet format Figure 3 6 represents a Receiver Report packet format 21 receiver Figure 3 5 Delay Since Last SR DLSR Time Diagram 28 0 3 8 16 31 V P RC PT 201 RR length SSRC of sender Gt SSRR_1 SSRC of the first source Fraction cumulative number of packets loss loss Extended highest sequence number received interarrival jitter last SR LSR delay since last SR DLSR a e
132. tatistics window of each VIC video stream consists of a grid with three columns Figure 2 1 The first column EWA Exponentially Weighted Average is the change since the last sampling period i e change over the last second the middle column Delta is a smoothed version of the EWA and the last column Total is the accumulated value since start up Clicking any of the buttons in the left column opens a Plot Window displaying the statistics for that parameter graphically UCL 99 Figure 2 1 contains example RTP statistics for video VIC streams vic Capitol Connection Capitol Connection GMU Tv Piel E3 7 7 Capitol Connection Copyright c George Mason Uni 14fis 148 kb s 14 a color Kilobits Frames Packets Missing Misordered VIC 2 8 4 Menu Help Quit Runts Dups vic plot window Capitol Connection Bad S Ver Missing Bad S Opt Bad Sdes mmm J Playout range Oto 20 2 div Dismiss Dismiss ge Ee Eg Figure 2 1 RTP Statistics in VIC showing video stream available statistics right side and a 10 second trace of missing packet data lower left corner Recorded July 1999 2 Robust Audio Tool RAT RAT is an audio conference application developed by U
133. teractive fully internetworked 3D worlds RTP is an integral part of the vrtp architecture used in both the streaming and monitoring components Figure 2 6 shows the functional design of the vrtp streaming behaviors component Universal client Internet 0 Figure 2 6 vrtp streaming behaviors component Brutzman 99 14 E INTERNET 2 SURVEYOR The university community has joined together with government and industry partners to accelerate the next stage of Internet development The Internet2 project is bringing focus energy and resources to the development of a new family of advanced applications to meet emerging academic requirements in research teaching and learning Advanced Networks 97 Surveyor is a measurement infrastructure that is being currently deployed at participating sites around the world Based on standards work being done in the Internet Engineering Task Force IETF Surveyor measures the performance of the Internet paths among partcipating organizations The project is also developing methodologies and tools to analyze the performance data The project aims to create the infrastructure and tools that will improve the ability to understand and effectively engineer the Internet infrastructure Advanced Networks 97 Surveyor monitoring workstations installed at NPS are expected to provide a controlled network environment supporting RtpMonitor work F DESIGN PATTERNS Design Patterns are reusable solution
134. tf avt rtp format guidelines 03 txt Internet Engineering Task Force 24 June 1999 Available at http www ietf org internet drafts draft ietf avt rtp format guidelines 03 txt Internet Engineering Task Force Request for Comments RFC 2327 SDP Session Description Protocol April 1998 Available at http ietf cnri va us rfc rfc2327 txt 213 Institute of Electrical Electronic Engineers IEEE Standard for Distributed Interactive Simulation IEEE Std 1278 1 1995 Macedonia M R and Brutzman D P MBone Provides Audio and Video Across the Internet IEEE Computer vol 27 no 4 pp 30 36 April 1994 Available at ftp taurus cs nps navy mil pub i3la mbone html Makofske D and Almeroth K MHealth A Real Time Multicast Tree Visualization and Monitoring Tool http imj ucsb edu mhealth June 1999 Rational Software Corp Rational Rose http www rational com products rose index jtmpl August 1999 Robinson J L and Stewart J A Multi MON an IPmulticast Monitor http www merci crc doc ca mbone MultiMON June 1998 Sarac K and Almeroth K SDR Session Monitoring Effort Global Sessions http imj ucsb edu sdr monitor global index html September 99 Schulzrinne Casner and others RTP A Transport Protocol for Real Time Applications Internet Draft draft ietf avt rtp new 04 txt RFC 1889 Internet Engineering Task Force 25 June 1999 Available at http www ietf org
135. the RTCP bandwidth to be allocated to Sender Reports RFC1889 recommends 25 of the RTCP bandwidth At this moment the RTPSessionManager is still not active The method startSession must be called in order to cause RTCP reports be generated and callbacks to the several listeners to be made This method must be called prior to the creation of any streams on a session The required parameters are e The session address as a RTPSessionAddress object e The time to live TTL e ARTPEncryptionInfo object if any encryption is desired 8 Receiving and Presenting RTP Media Streams After RTPSessionManager has been started any receiving stream will generate a RTPRecvStream object and a NewRecvStreamEvent event In the update method of the interface RTPRecvStreamListener the RTPRecvStream object can be obtained by the method getRecvStream of NewRecvStreamEvent By retrieving the DataSource from the RTPRecvStream object and passing it to the Manager we can create a Player for the received stream The class PlayerWindow supplied by Sun receives a Player plays back the media audio or video and creates a control window Figure 4 5 contains a collaboration diagram describing the sequence above This collaboration diagram uses standard notation for showing logical relationship between instantiated objects as specified by UML Booch et al 97 50 event NewRecvStreamEvent 1 update event 2 stream getRecvStr
136. the experimental results achieved and problems observed Finally Chapter VIII presents conclusions and provides recommendations for future work THIS PAGE LEFT INTENTIONALLY BLANK Il RELATED WORK A INTRODUCTION This chapter presents some related work in the area of RTP monitoring RTP monitoring is closely related to the RTCP protocol but some applications discussed here combine RTCP data with multicast route tracing improving the monitoring quality Applications are considered in into two categories media conference applications with monitoring features and dedicated monitors This chapter also contains pertinent information about the vrtp protocol and the Internet 2 Surveyor project B RTP MONITORING IN MEDIA CONFERENCE APPLICATIONS Most conference applications used in MBone can display some sort of RTP monitoring data As the emphasis of these applications is media presentation and stream quality assessment the statistical data is usually not enough for network administration or diagnostic purposes The RTP statistics features of some conference applications are described here 1 Video Conferencing Tool VIC VIC is a video conferencing application developed by the Network Research Group at the Lawrence Berkeley National Laboratory LBNL in collaboration with the University of California Berkeley UCB The software was improved by University College of London UCL The latest version is 2 8ucl4 UCL 99 The RTP s
137. tocolDataUnit pdu public int public void number th takes the timestamp from the DIS pdu and sets the SSRC be transmitted assigns a sequenc static variable sequenceNumber new increments th next sequenc number kept by a nexu incrementSequenceNumb assigns as a times timestamp pdu getTim assigns the common SSRC new UnsignedInt return Returns return the header siz sequenc estamp SSRC mySSRC the size of the header length return RtpHeader sizeOf Serializes the header Qparam outputStream the stream serialize Da creates the first a UnsignedByte RTP PADDING 32 UnsignedByte secondBy RIP PAYLOAD serializes firstByte serialize ou secondByte serialize o sequenc timestamp serialize ou SSRC serialize outputs return firstByte into a Da UnsignedShort nextSequenceNumber number variable tamp the Dis Java Vrml timestamp taOutputStream that will receiv the serialized header taOutputs nd second new UnsignedByte RTP_EXT te new E FOR DIS ENSION 16 UnsignedByte tputStream utputStream Number serialize outputStream tputStream tream 211 tream outputStream byte from the header RI P_VERSION 64 RTP CSRC COUNT RTP MARKER
138. transport layer protocol used for sending or receiving the stream of RTP packets in this session SessionRemAddr Taddress the remote destination transport address on which the RTP data packet is sent and or received SessionLocAddr Taddress the local destination transport address on which the stream of data packet is being sent and or received SessionIfIndex InterfaceIndex this value is set to the corresponding value from the Internet Standard MIB This is the interface that the RTPStream is being sent to or received from SessionSenderJoins Counter32 the number of senders that have been observed joined the session since SessionStartTime see below SessionReceiverJoins Counter32 the number of receivers that have been observed joined the session since SessionStartTime see below Not applicable Not implemented Not implemented Not implemented Not applicable Not implemented Not implemented 192 It can be added JMF uses UDP as the transport protocol Extensibility to other protocols is possible but not provided It can be added In RTP Monitor the session transport address names the directory where the files are created and updated e g session224 2 2 2port88888 It can be added Not part of native JMF statistics It can be derived in an JMF application by monitoring NewRecvStreamEvents Not part of native JMF statistics It can be derived in an JMF applic
139. tream addActionListener this changeStream setEnabled false changeStream rLab new Label 5 rText new TextField 5 for int 1 0 ii lt 5 rLab ii new Label rField ii rLab ii setBounds 500 170 ii 25 100 20 add rLab ii rText ii new TextField rText ii setBounds 605 170 11 25 90 20 rText ii setEditable false add rText ii feedbkLabel new Label Feedback Reports feedbkLabel setBounds 510 315 100 20 add feedbkLabel feedbkFieldsLabel new Label Username Fraction Lost Jitter Packets Lost feedbkFieldsLabel setBounds 420 340 350 20 add feedbkFieldsLabel feedbkArea new TextArea 0 0 TextArea SCROLLBARS VERTICAL ONLY feedbkArea setBounds 410 360 360 180 feedbkArea setFont new Font Courier Font PLAIN 12 feedbkArea setEditable false add feedbkArea setVisible true streamTable new Hashtable this addWindowListener new WindowAdapter public void windowClosing WindowEvent System exit 0 167 public void actionPerformed Action Takes action when buttons are selected if e getSource start set if if e getSource start Enabled false Event e modPrefDialog intervalText getText
140. tring return a string Ee private String fillBlanks String strin int size StringBuffer spaces new StringBuffer for int ii 0 ii lt size Spaces append String newString new String strin spaces return newString substring 0 size 175 Runs an external program specified in the preference menu to display output files param locator the session RtpMediaLocator param fileName the name of the file to be displayed S private void runViewer String locator String fileName String prefix Runtime Runtime getRuntime try RtpMediaLocator rtpml new RtpMediaLocator locator String session rtpml getSessionAddress String port new Integer rtpml getSessionPort toString String dir new String session session replace port port prefix new String dir statistics catch MalformedURLException e System out println e getMessage return try String prog new String modPrefDialog viewerText getText prefix fileName Process r exec prog catch IOException e System err println e getMessage Method called upon executing class RtpMonitor If there is no argument an object of class RtpMonitor will be instantiated and executed otherwise the same will happen with an RtpMonitorCommandLine object public
141. uk multimedia software rat June 1999 UCL Networked Multimedia Research Group Session Directory UCL Networked Multimedia Research Group August 1999 Word Wide Web Consortium Extensible Markup Language http www w3 org XML August 1999 215 THIS PAGE LEFT INTENTIONALLY BLANK 216 INITIAL DISTRIBUTION LIST Defense Technical Information Center No Copies 8725 John J Kingman Rd STE 0944 Ft Belvoir Virginia 22060 6218 Dudley Knox Library Naval Postgraduate School 411 Dyer Rd Monterey California 93943 5101 Chair Code CS Department of Computer Science Naval Postgraduate School Monterey California 93943 5121 Dr Michael J Zyda Code CS Zk Naval Postgraduate School Monterey California 93943 5121 Dr James Eagle Code UW Naval Postgraduate School Monterey California 93943 5121 Dr Don Brutzman Code UW Br Naval Postgraduate School Monterey California 93943 5121 Rex Buddenberg Code SM Bu Naval Postgraduate School Monterey California 93943 5121 Don McGregor Code C3 Naval Postgraduate School Monterey California 93943 5121 Dr Michael R Macedonia Chief Scientist and Technical Director US Army STRICOM 12350 Research Parkway Orlando FL 32826 3276 217 10 11 12 13 14 15 16 17 Drej Mark 2 2 et iet t Department of Computer Science and C3I Center George Mason University Fairfax VA
142. viors and results bugs 11 Running the program in other directory 12 Reinstallation recommendations SO NI Cn 05 79 1 Execution a In the command line type cd vrtp rtpMonitor java org web3d vrtp rtp RtpMonitor b or run the batch file rtpMonitor bat in the c vrtp rtpMonitor directory There is a Windows shortcut to this file in the same directory This shortcut can be copied to the Desktop to create an icon for the rtpMonitor program Using this call with no arguments the GUI version of the program will be executed The following window is presented 2 RtpMonitor OF xi File Bookmarks Preferences Help Session Name Start Stop Global Statistics Total Bytes Bad SDES Packets Stream 7 Total Packets Bad BYE Packets Lost PDUs RTCP Packets Local Collisions Processed PDUs SR Packets Remote Collisions MisOrdered PDUs Bad RTP Packets Looped Packets Invalid PDUs Bad Packets Failed Transmission Duplicate PDUs Bad SR Packets Unknown Bad RR Packets Feedback Reports Active Participants Passive Participants Username Fraction Lost Jitter Packets Lost 80 Defining a session In the session box enter the session address port ttl as in the example below rtp 224 2 125 60 55690 127 where Multicast IP address 224 2 128 60 RTP port 55690 TTL 127 3 Sess
143. wledgements and retransmissions UDP just sends single packets with no guarantee that the packets will be received at the other side RTP does not provide all the functionality required by a transport protocol It is intended to run over some transport protocol such as UDP primarily in multicast mode TCP is not suitable for real time audio video transfers because packet loss implies in retransmissions that affect delay sensitive data Also TCP does not support multicasting Despite the implication of its name RTP does not provide any means to ensure timely delivery or to guarantee a desired quality of service In fact RTP was designed to satisfy the needs of multi participant multimedia conferences where the loss of some packets or some small delay will not affect the session significantly 17 Basically the RTP header provides a sequence number and a timestamp in each packet allowing the timing reconstruction of the receiving stream Additionally RTP header specifies a payload type allowing different data formats to originate from different senders in a single session Further parameters in the RTP packet header are defined a media specific manner RTP is used together with the RTP Control Protocol RTCP which provides mechanisms of synchronization source identification and quality of service feedback C RTP This section summarizes RTP which is formally described in RFC1889 Schulzrinne et al 99 1 RTP Units Mi
144. xample of a Processor internal operation In this example the media has one audio and one video track that are demultiplexed and processed individually At the end they are multiplexed again and become available as another DataSource Manager provides access to a protocol independent and media independent mechanism for constructing and connecting DataSources Players Processors and DataSinks A DataSource can be created by the method createDataSouce with a 40 parameter specifying either a MediaLocator or URL A Player or Processor can be created by the method createPlayer or createProcessor The argument may be a DataSource a MediaLocator or a URL In order to create a Player or Processor from a MediaLocator or URL the Manager first tries to create a DataSource At last for creating a DataSink a Manager has to receive a DataSource and a MediaLocator as argument The DataSource represents the input to the DataSink and the MediaLocator describe the destination of the media to be handled by the DataSink Renderer Plug in on Codec Effect Plug in Effect Plug in Plug in Demultiplexer Mutiplexer Plug in O Plug in Track 2 Renderer Plug in Processor Figure 4 2 Processor Decomposition Sun 99 The JMF class hierarchy can be extended by implementing new plug in interfaces to perform custom processing on a track or by implementing new DataSources Players Processors or DataSinks New plug ins
145. xer Translator and Monitor A Mixer is an intermediate system that receives streams of RTP data packets from one or more sources possibly changes the data format combines the streams in some manner and then forwards the combined stream A mixer sends its data just as if it were a new source A Translator is an intermediate system that forwards packets without changing its source description Translators can be used as devices to convert encodings such as replicators from multicast to unicast and such as application filters in firewalls A Monitor is an application that receives RTCP packets sent by all participants to estimate the quality of service for distribution monitoring fault diagnosis and long term 18 statistics The monitor is likely to be built into the applications participating in a session but it may also be a separate application that does not send or receive RTP data packets such as third party monitors RTP is designed to connect several end systems in single or multiple sessions An end system sends and or receives RTP data packets In addition RTP supports the notion of Translators and Mixers which can be considered intermediate systems at the RTP level The need for these systems has been established by experiments with multicast and video applications especially for dealing with low bandwidth connections and firewalls 0 2 RTP Header A RTP header precedes each RTP packet Figure 3 1 represents
146. xt hour delete deletes the previous hour file if it exists if hourlast exists hourlast delete flgFirstDataMin true Method that will update the files transfering data from statisticsLastReport txt to the appropriate files param time the current time as a Calendar object public void update Calendar time rightNow time displays the current time on the console System out println rightNow getTime toString minuteRangeNow represents a block of five minutes int minuteRangeNow rightNow get Calendar MINUTE 5 int hourRangeNow rightNow get Calendar HOUR OF DAY String dateNow new String rightNow get Calendar MONTH 1 rightNow get Calendar DAY OF rightNow get Calendar YEAR 148 if it is the fir if flgFirstDataMin minuteRange mi hourRange hour st report of the session nuteRangeNow RangeNow dateRef dateNow saveDateRef dat flgFirstDataMin if minuteRangeNow if it is new appends data Ref false minuteRange block of five minutes from the five minutes file to the last hour file fix concatenate pr if min5last exi min5last dele rename last f min5 renameTo mi minuteRange mi if hourRangeNow if it is a appends da sts te ive minutes file to previous five minutes file n5last nuteRangeNow
147. xt setEnabled false intervalPresText setEnabled false endChoice setEnabled false viewerText setEnabled false xj EE 153 Saves the preferences in the file preferences txt public void savePreferences try DataOutputStream output new DataOutputStream new FileOutputStream preferences txt output writeBoolean partBox getState output writeBoolean playBox getState output writeBoolean recordBox getState output writeUTF intervalText getText output writeUTF intervalPresText getText output writeInt endChoice getSelectedIndex output writeUTF viewerText getText output close catch FileNotFoundException e System out println File not found 4 getMessage catch IOException e System out println IOException getMessage Loads the preferences from the file preferences txt 34 private void loadPreferences try DataInputStream input partBox setState input playBox setState input recordBox setState inpu interval intervalPresText setTex endChoice select input viewerText setText inpu input close catch FileNotFound catch IOException e lText setText input readul new DatalnputStream new FileInputStream preferences txt readBoolean readBoolean t readBool

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