Home

The NCTUns 1.0 Network Simulator GUI User Manual

1. EE Fig 6 The packet animation player of the NCTUns 1 0 Summary In this chapter we have briefly discussed the features and capabilities of the NCTUns 1 0 network simulator After reading this chapter readers now should have a high level view about the NCTUns 1 0 network simulator In the next chapter we will present how to install the NCTUns 1 0 network simulator package To enable readers to quickly get a feeling about the operation of the simulator a short tour about running a simple simulation case will be presented Getting Started his chapter presents a simple tour to help i readers quickly learn how to us the NCTUns 1 0 network simulator First we give instructions on how to install the NCTUns 1 0 network simulator package on a single machine Next we use step by step instruc tions to show that a user can immediately run a simple simulation case Installation and Configuration In the following we assume that when installing the package the user uses the default settings A user first extracts the package from the CD or downloads it from the web site at http NSL csie nctu edu tw nctuns html After reading the installation explanation and running the installation script a sub directory named nctuns will be created in the usr local directory which in turn has several sub direc tories The name of these sub directories are bin etc tools BMP and lib res
2. sim directory a directory named mainFileName results is also created This directory will store the generated simulation results when they are transferred back to the GUI program after the simulation is done It is important to note that before a user runs a simulation case he or she can still switch the mode back to the Edit Topology or even the Draw Topology mode to change any setting of the simulation case However when the mode is switched back into the Run Simulation mode all simulation files will be re exported to reflect the most recent settings Before a user runs a simulation he or she must make sure that the dispatcher and coordinator are already running Suppose that the user uses the single machine mode of the NCTUns 1 0 he she will have to run up the dispatcher and coordinator programs first The following procedure assumes that the user uses the single machine mode If the user uses the multiple machine mode to use a simulation service center that is already set up by some person or institute he she can skip the following two steps 1 Run the dispatcher program located in usr local nctuns nctuns bin 2 Run the coordinator program located in usr local nctuns bin The default values of the parameters needed by this program is stored in usr local nctuns etc coordinator cfg Now we need to let the GUI program know the IP address and port number used by the di
3. During the play of a packet animation trace a user can change some options of the GUI program to suit their needs These options are described below Time Bar The time bar contains icons and buttons related to packet animation Now we will examine every function from left to right non OM Onin monn LILILI LILILI LILILI LILILI Current simulation time timer This timer icon shows the current simulation time By double clicking the icon a user can set the timer to any desired simulation time This feature is very useful when the traffic is sparse This is because the user does not need to wait a long time before seeing packet transfers Instead the timer can go directly to any interesting time Of course to know at what time there is a packet transfer in the log file the user needs to peek into the trace file There is a utility program printptr that can convert a binary packet animation trace file into a text trace file for this purpose This program is located in usr local nctuns tools O TEDIN mN GD e A Simulation time bar The time bar shows the packet animation progress in a period between two times called a time window Users can drag the time bar knot to any desired time Two icons are provided here to change the size of the time window by a factor of 10 That is the time window size can be either increased 10 times larger or decreased 10 times 43 smaller A user can conveniently perform this job
4. Inter Process Communi cation The NCTUns 1 0 network simulator uses a distributed architecture to support remote and concurrent simulations As such an Inter Process Communication mechanism is needed to connect all components together In the chapter many commands that are related to controling the execution of simulations are presented References 1 S Y Wang and H T Kung A Simple Methodology for Constructing Extensible and High Fidelity TCP IP Network Simulator IEEE INFOCOM 99 March 21 25 1999 New York USA 59 60
5. Under Speed tab the tick time and simulation speed can be specified Note The GUI user is discouraged to change these settings Right now for the beta version only the As Fast As Possible mode is supported 33 Simultan Spoed GU Syetem command Onetick ig ranmmord Eimuaiw Spaan E As tet as pocsble As tact as ihe makeri clock Under GUI tab the ratio of meter pixel can be specified e eae BES Te amd ation Speed E System connand Proportion 10 meber piel 34 Under System command tab to be executed system commands and their output file names can be specified here A system command is a command that when executed will get or set an object s value at a specified time The output of the command will be saved to the specified output file which will later be transfered back to the GUI program when the simulation is finished In addition to getting setting a single object s value the values of all objects of the same kind can be get or set at the same time to take a global snapshot of the network For example this function can be used to take the snapshot of the current routing tables of all routers This global snapshot information can help a researcher study the convergence of a routing protocol Tl et Simuation Speed GU Systm command Output le nar Time the starting time for triggering this command Command the system
6. gt skip the animation time window by one time window size in the backward direction Qtps 100 The first option eoms 4 is to alter the frame rates of packet animation Users can change the frame rate by left clicking the increase decrease icons or directly typing in a number as input The second option 100 is to change the animation speed Using a larger value will speed up the animation by using a larger time quantum when advancing the time However more packet transfers will not be displayed This is because the packet transfers that occur during the time leap will not be displayed Animation Effects Wired network and wireless network have different characteristics Therefore we demon strate their corresponding animation effects separately Wired Network We use two screen shots to illustrate and explain wired network packet animation te T Hbu bmili Seen TEI 1S eee te m 2 TIES 2 Oo eS i oe er 2 oP bein packet drop amp collision represented by cross 1 A link is painted yellow if there is any packet flowing on it 2 A packet is depicted by an arrow with a DATA annotation 3 A collided packet is depicted by an arrow with an cross mark on it 4 During a packet transfer If a link is painted in red it means that this link is an intermediate link for this packet In contrast if this link is painted in yellow it means that either the source of this link is the
7. It s convenient for a user to save mobile nodes current moving paths to a file and later reload and reuse them Generate Random Waypoints There are two ways to help a user generate random waypoints The first one is to generate the next waypoint randomly for each mobile node When the user clicks the button one more random waypoint will be generated for every mobile node The user can press the button continuously to continuously generate more random waypoints Generate the next point The other way is to automatically generate random waypoints until the specified time in virtual time e g 10 sec has elapsed a sequence of points until E Sec Generate Infrastructure Node IP and Mac Addresses This command can automatically generate IP and MAC addresses for a large number of infra structure mode mobile nodes In the Getting 30 Started Chapter we mentioned that the GUI program will not automatically generate and assign IP addresses to an infrastructure mode mobile node because it does not know to which subnet that infrastructure mode mobile node should belong However to save the user a lot time spent on manually assigning IP addresses to a large number of infrastructure mode mobile nodes the GUI program still provides this function here If the user knows to which subnet a group of infra structure mode mobile nodes should belong e the subnet ID he or she can use this function to insert a group o
8. icon Fener C T Fiama pa j Ferir Fpi e a cs evs Lome Ee do le Pe ae E F U ifarra JE i EEEN In the second way a user can use the node editor to specify the protocol module parameters used inside a network node To enter the node editor first a user double clicks the node s icon to pop up its dialog box Then the user double clicks the node editor button in the dialog box The following shows the popped node editor and the protocol modules used by the router a l i e HHHH i ns L One important task in the Edit Property mode is to specify which application programs traffic generators will run on which nodes during simulation to generate network traffic Application programs are allowed to run on hosts routers and mobile nodes including both the ad hoc and infra structure modes Therefore in these devices dialog boxes there is an Appli cation tab for a user to specify the commands for launching the user s desired application programs The following shows the Application tab Pla i T Application Ceram im Hoot ait te rare For example suppose that a user wants to sets up a greedy TCP connection between two nodes He can specify the invocation command rtcp p 8000 on the receiving node s Application tab and specify the command stcp p 8000 1 0 1 2 on the sending node Application tab In this case rtcp a
9. a RED module Step 0 The initial protocol module chain is shown as follows Step 1 Then we choose the RED module from the top and place it in the middle working area The resulting screen is shown below 39 Step 4 Then we link modules together To link two modules together a user performs the same operation as he she does when placing a link between two nodes in the topology editor At the top and bottom of a module there is a small box A link must start and end on these small boxes After linking up modules the result is shown below Step 2 Then we delete the FIFO module The result is shown below me Step 5 Since the job is finished now we redraw mee the node editor to make it look beautiful The ela result is shown below View Module Parameters To view a module s parameters a user can double click a module Then its module parameter dialog will appear The following shows the parameter dialog of the ARP module Parameters setting ARP Mode Flush Time Interval 3000 imsi Build ARF Table In Advance 7 D I a Ta TT EL Lo La lo _ Ai File Mame ftestbyHsivun Wo_P1 arp m Run Time Query Create Your Own Module The NCTUns 1 0 provides a simple method for a user to add a new module to the node editor Detailed procedure is documented in the NCTUns 1 0 Module Writer Manual Here let s take the ARP module to briefly
10. assign an appropriate IP address to an infrastructure mobile node Due to the reason this task thus must be left to the user as his or her responsibility Beside config uring the IP address manually the user also needs to manually configure the gateway IP address for the infrastructure mobile node Otherwise its packets cannot get forwarded beyond the subnet that it is attached to Configuring the gateway IP address can be done in the mobile node s dialog box under the Wireless Interface tab A user should be aware that if he she switches the mode back to the Draw Topology mode when he again switches the mode back to the Edit Property mode nodes IP and MAC addresses will be re generated and assigned to layer 3 inter faces Therefore the application programs traffic generator now may use wrong IP addresses to communicate with their partner In this mode since the IP and MAC addresses and the port ID of an interface are already automati cally generated and assigned the GUI will automatically show these information when a user moves the mouse cursor and place it over the blue interface box on the screen for a while This can conveniently let the user see the results of the automatic IP and MAC address and the port ID assignments Beside automatically generating IP and MAC addresses to save a user s time the GUI program also automatically and silently perform many tasks for the user Many of these
11. by left clicking the time plus icon U or the time minus C icon Right at the bottom of the time bar a red vertical line indicates that a wired packet trans mission starts at this time In a similar way a green vertical line indicates that a wireless packet transmission starts at this time Note that the ending times of packet transmissions are not depicted here Therefore it may cause difficulty if a user wants to move the time knot to the time when a packet transmission exactly ends Thus these vertical lines are depicted here for reference purposes only To know exactly when a packet transmission starts and ends a user can use the printptr utility program to convert the binary animation trace file into a text file and then search it in the file gt Tl m Animation playing buttons Animation playing buttons are provided to alter playing sequences They can be executed by left clicking their corresponding icons plays the animation If a user clicks it while the animation player is idle the player will start to play the simulation trace If a user clicks it while the animation player is already running the time bar knot will jump directly to the nearest time where there is a packet transmission This feature is very useful when the traffic is sparse pauses the animation Hl stops the animation Haf skip the animation time window by one time window size in the forward direction
12. command string Output file name the name of the output file The system commands provided by the NCTUns 1 0 network simulator are listed below Their syntax and meanings are also presented below Set set a value to a variable in a module Set node port module tag value Get get the value of a variable from a module Get node port module tag GetAll like Get but get the requested variable s value from the same modules used in all ports of all nodes GetAll module tag Note that a tag is a string associated with a particular variable declared and used in a protocol module A variable here can be a single value variable e g a FIFO queue s maximum queue length or a multi column multi row table e g a switch table that has multiple IP address MAC address mapping entries It is the protocol module developer s job to write a command function in his her module to recognize a tag and get set the value of its corresponding variable More information about the get set command can be found in the Module Developer Manual Running the simulation Run Pause Continue Abort Reconnect gt Disconnect co Ub mit the simulation command list Menu gt Simulation gt Run Pause Continue Stop Abort After a user switches to mode 3 the user can start running the simulation by executing commands in this group NCTUns 1 0 has a convenient way to handle the progress of a sim
13. dialog a user can specify whether routers should run routing daemons e g RIP OSPF to construct their routing tables or their routing tables should be calculated in advance by the GUI program Run time routing table content lookup 2I can also be performed by clicking the Show routing table button when a simulation is running e Switch 4itoh iD Coan tng Moe ecinr Lx cancel e Access Point AP property Wireless interface Wireless Interface D Frequency frenge q 30 00000 Under the wireless interface tab a user can examine the interface attributes e g the used frequency channel and the wireless signal trans mission range 28 e Mobile Node Ad hoc and Infrastructure mode z Piok 10 Hare HODES an i Fath Orania imcraca Applicatan Sigic hap core f Ara imei D S660 J6E 10 i Add 1 63A 000000 505 000000 Th22kis2 Z a35 000000 S55 000000 31 3730 age 0000 432 000000 ii A oe 4 284 000000 61 5 000000 AS a22 bon 5 220000000 397 000000 TIIMIN Leirie HG a Mavirg Pah Biring speed fi canna rare Genemi one nore random we pomt Gener abe Inport a seance of palrni trom ike Eeponitha cumani moving pain io tle OEE 3 regente Of randan war pede intl fo P Gener ae r Alter nggiyiy Aitua node kaap nong spaced Lekt 0 Emp athall ine hade edini z Show p h Show tanmon range Show wiererence range A powerful
14. editing the configuration file at SNCTUNSHOME etc dispatcher cfg and restarting the dispatcher Currently the email field in the dialog box is optional In the future version of the NCTUns this information will be used by the dispatcher to send back a job finished notification email to the user e Switch to Run Simulation Mode When the network topology and the properties of the network are set a user can choose to run the simulation on line or submit it as a background job Before he she can do that he she needs to switch the GUI mode to the Run Simulation mode The user can do this by executing File gt Operating Mode gt Run Simulation as shown in Fig 2 Tes OA Fede Fee bratr fel hm u Fig hip ere z Beko Eb bps peep lt n an a A G qp a Hem Im H Fig 2 Switch to the Run Simulation mode Basic Simulation Operation With the friendly GUI design it is very easy to run a network simulation Most of the commands needed are located in the Simulation menu see Fig 3 We will explain the usage of each of these commands in the following sections Fig 3 the Simulation menu e Run a Simulation After switching to the Run Simulation mode a user can submit his her job to a simulation server by executing the Simulation gt Run command Three different outcomes may be possible after the command is executed In the first outcome the simulation is submitted successfully In t
15. here They can be deleted stopped aborted or retrieved Setting the simulation Menu gt Setting gt Dispatcher Job dispatcher IP address hao E Pia E Fot fiom Leer inim ation lka nare himu Passim E Enai address frun the dispatcher setting dialog This dialog sets up the IP address and port number used by the dispatcher The GUI user s login account and password for using the remote simulation server should also be entered here It is VERY important that the account name of the GUI user used on the local GUI machine and that used on the remote simulation server should be exactly the same Otherwise the network simulator cannot work correctly For the single machine mode the user name specified here MUST be the same user account name by which the user logs into this local machine Otherwise the simulation cannot run correctly If the user is using the single machine mode the IP address entered here can be 127 0 0 1 the IP address of the loopback interface and the port number must be the same as the CLIENT_PORT specified in the dispatcher cfg Menu gt Setting gt Simulation the simulation setting dialog Under Simulation tab the total simulation time in virtual time and the maximum of X Y Z coordi nates should be specified Seer Snukio Spaed GU Syston command Slmuaiion tne fas TEL Ham s ini retur bias 1150 reter Wia 150 meter F iGenerate packs aninaton tog Me pr
16. mmn paa F yu ee rat feili jth marn bya a a a alan ae ele re Ee See Ue Lee a a oe ed Cont igurat ion uth Lita i abome to che thie login eL Tau haw wil command console login screen The command console is a very useful feature A user can also use this console to launch application programs at run time to generate traffic For example while the simulation is running the user can open a sending node s command console to launch the step p 8000 1 0 1 2 program and open a receiving node s command console to launch the rtcp p 8000 program assuming here that the receiving node has an interface configured with 1 0 1 2 In addition executing the ping command in a command console is also very useful This is because doing this can help a user find whether the routing path between two nodes is correctly set up during simulation Beside the above shared tabs each device has its own ones that will be presented below e Host H rrei j E Fbi ama pomi Appii am iire l Sip irae corea inp e rare Hada aiin Hub EARTEN Down time Ata AAA Stat 3 Add Delete hub Node editor Cancel Because every port of a hub must use the same bandwidth A field is provided here to set up the hub s bandwidth e Router Freier fF He Pone BETT mgpa prsa mme p le be ehoe ain ryti fee Baar iim ips Fay airy Oe ao aa m E Guid in siea In this
17. real source destination of the packet or the destination of this link is the real source destination of the packet 5 The arrow length is determined by the packet s packet length Therefore a user can expect that the arrow length is proportional to the packet length In fact a packet s arrow length on a particular link is determined by the transmission time of that packet on that link relative to the signal propagation delay of the link Wireless Network Similarly two screen shots are given as illustrations ECP 1 Be ok Ebh Hi Hille Teele fe H a k i E z i i 1a is y L i fey i i n E amp a a L a m g E k amp hy h 4 k h k ak i b i Bj h m i au 15 a i Cs fe z ti h FE pii FE FTI wireless packet transmissions IEEE 802 11 DATA frame 45 oE 4 h li E a k 4 IL 4 4 he hy amp 4 he oe IL amp i Sa i k b i bi al y W 7 i k a Li dii a 4 4 h ioe Gt 4 i a 4 he hy G k 4 k E I 7 f GC 2 a8 oy s EF z 1 amp k k x 4 k L oe oS a lear vrata an A ee TEH cs hii g Wireless transmission IEEE 802 11 ACK frame 1 Two concentric circles are centered around a transmitting node The smaller circle stands for the transmission range while the larger one stands for the interference range Within the interference range a station can sense the existence of other nodes signals However only when the receiving station is
18. tasks are performed underground to automatically correct a user s configuration mistakes This is to avoid generating wrong simulation results or even causing simulation crashes For example the GUI program will automatically set the promiscuous mode of the 802 3 MAC modules that are used inside a switch to ON no matter how the user set them The promiscuous mode is default to OFF because the 802 3 MAC modules used inside hosts and routers need to filter out unwanted frames This ensures that frames can be forwarded by the switch without any problem Otherwise if the promiscuous mode is not turned ON frames will be discarded by the switch s 802 3 MAC modules Another task that the GUI program does for the user is to ensure that all interfaces that connect to a hub uses the hub s bandwidth as their interface bandwidth and the operating mode of these inter faces 802 3 MAC modules all be set to half duplex In the GUI program a user can indepen dently set different bandwidths for different inter faces and set a 802 3 MAC module s mode to either full duplex or half duplex without considering whether these interfaces are connected to a hub These wrong configurations surely will generate wrong simulation results and may even cause crashes This kind of misconfigu ration bug is difficult to detect for a careless user As such the GUI program does several under ground tasks to save the user s time an
19. the network topology he or she will need to explicitly switch the mode back to the Draw Topology mode However when the mode is switched back to the Edit Property mode many settings that were automatically generated and assigned by the GUI program will be re generated automati cally by the GUI program These new settings may be different from the old settings For example the IP and MAC addresses automatically assigned to a layer 3 network interface may have been changed The user thus better re checks the settings for application programs traffic generator that he she has specified while he she was in the Edit Property mode The is because these appli cation programs now may use wrong IP addresses to communicate with their intended partners 2 Move the cursor to the toolbar WX Moomersvy ag 3 Left Click the router icon amp on the toolbar 4 Left Click somewhere in the blank working area to add a router to the current network topology which is empty now 5 Left Click the host icon 4 on the toolbar Like step 4 let s add three hosts to the current topology The result is shown below iP Tri bruen Er mm e Sem fe ww 4 i A O a SA AHF I eo 6 Now we want to add links between the hosts and the router Left Click the link icon 7 from the toolbar to select it 7 Left Click some host and hold the mouse button Drag this link to the router Then release the mouse l
20. this time asking the user to specify one As explained before to greatly save the user s configuration time the IP and MAC addresses used by layer 3 network interfaces are automati cally generated and assigned by the GUI program In addition the MAC addresses used by layer 2 network interfaces are automatically generated Layer 3 interfaces are used by layer 3 devices such as hosts routers and mobile nodes Layer 2 interfaces are used by layer 2 devices such as switches and wireless LAN access points 11 12 The generated IP addresses use the 1 0 subnetID hostNumOnThisSubnet format where subnetID and hostNumOnThisSubnet are automatically assigned As such the NCTUns 1 0 network simulator can allow a simulation case to have up to 254 subnets subnet ID 0 and 255 are excluded for broadcast purposes each of which can have up to 254 nodes hostNum 0 and 255 are excluded for broadcast purposes That is in total 254 254 64 516 nodes can be supported in a simulation case Although in theory the NCTUns 1 0 can support this large number of nodes in a simulation case in practice this is rarely done This is because each layer 3 interface needs to be simulated by a tunnel interface and currently we create only 4 096 tunnel interfaces in a UNIX machine So precisely speaking currently the NCTUns 1 0 can support any simulation case using up to 4 096 layer 3 interfaces This means that currently the maximum number of mobil
21. to the GUI program and then saved in the user s local hard disk Suppose that the simulation case s topology file is named test tpl Then the name of the resulting packet animation trace file will be test ptr Later when the user wants to do post analyses about the simulation results he or she can use the Packet Animation player to play back the animation This is a very useful feature for both educations and research purposes Reloading Simulation Results To watch a previously generated packet animation trace a user should open its corresponding topology file first menu gt file gt open FRE gre esip Fie fpe ipaa iie T 7 The user then switches to the Play Back mode The GUI program then will automatically reload the simulation results including the packet animation trace file Since the animation file is usually very large this process may take a while To give the user an idea of the progress a progress bar will be shown during the loading process nctunsclient Loading Uswlocalnctuns bintestl resultstestl ptt status window for loading a packet animation trace file After the animation trace file is loaded the user then left clicks the start icon of the time bar located at the bottom The player will then start playing back the logged packet transfer animation Some control button icons of the time bar General Options for Packet Animation
22. use this console to log into the current node the node whose dialog box is shown right now A xterm terminal window will appear In this terminal window a user can run the tcpdump program to capture packets passing through one of this node s interface For a router suppose that the user wants to capture the packets flowing through one of its interfaces Further assume that this particular interface is configured with 1 0 2 3 IP address The user can first type in ifconfig a command to find out the information about all of the router s interfaces From the output the user can find the name of the desired interface which is configured with 1 0 2 3 In the NCTUns 1 0 network simulator an interface s name is in the fxpX XX format where XXX is the interface s port ID After finding the name of the desired interface the user now can type in the following command tcpdump 1 fxpXXX to launch the tcpdump program GE K Beppe Pee ee ele jig eet tht ERRATA rt ie for er releees Firet ar jitu uke F Tu j Freee ce Tem Hered aed FAD romarir mo gi hiipii uaa Foa JET mm7 arri Sling with rie madi Lies an be Seed ba ea in LE ps fae Free ore Vf iha dee dictrcytion bar been invbelded Hey rma ales resi jebla Porestted jn dorth te F gp hill Fee a phim or probles plass tep bha cert o PER i bliig RE Fpj EIFLE HP hhli ji Ti Hiki a oa Queetion be the etic reo wili dict imh j wich Pee a iren y bpa fbi HA CD I
23. within the trans mission range of the sending node will the packets be guaranteed to reach the receiving station successfully 2 A data packet is depicted by an arrow with a DATA annotation 3 An acknowledgement packet is depicted by an arrow with a ACK annotation 46 Summary This chapter presents the Packet Animation Player capability of the GUI program Relevant options are covered and some animation effects are illustrated and explained in detail Performance Monitor erformance monitor is a useful tool that p graphically generates and displays graphs of some performance metrics It can help users monitor a links utilization or a TCP connection s throughput This chapter gives an overview of the functions that the performance monitor provides Running Performance Monitor Choose Tool gt Plot Graph This will launch the performance monitor s window mie erie eh Graph Fici performance plot window From the performance monitor window choose File gt Open Then a user can select a desired log file to open The user then can left click the start icon gt of the time bar As the packet animation proceeds the performance monitor window will display the corresponding performance curves over time Note that the performance monitor can be used as an independent tool without the animation player running up That is it can read a log file generated by any other application
24. y axis X tics This field sets the interval of the x axis Y min This field sets the minimum value of the y axis Y max This field sets the maximum value of the y axis Show grid This field sets whether the grids should be visible Line Points Specify that the performance curve should be drawn using straight lines to connect adjacent points State Transition Specify that the performance curve should be drawn using horizontal lines to connect adjacent points X axis width Specify how many seconds data should be displayed in this graph window e Global Setting This option associates a graph source with a log file Up to six associations can be specified in this dialog To select a log file from the local host a user can press the Browse button e Graph Mode This option controls how to display a perfor mance curve Currently there are two modes The first mode is line points while the second mode is state transition The following two screenshots clarify the differences between these two modes Irgi Title mh Lie raph Titla im en i FEI fi Summary This chapter is about Performance Monitor The functions and relevant settings of the performance monitor are discussed Users can make good use of this tool to help them analyze performance results Users can also easily take interesting snapshots of some performance curves t
25. 0 adopts a distributed architecture It can be viewed as a package consisting of eight components 1 The first component is the GUI program by which a user can edit a network topology configure the protocol modules used inside a network node specify mobile nodes moving paths plot performance graphs play back the animation packet transfer trace etc 2 The second component is the simulation engine which provides basic but useful simulation services e g event scheduling timer management and packet manipulation etc to protocol modules 3 The third component is the set of various protocol modules each of which implements a specific protocol or function e g packet sched uling or buffer management 4 The fourth component is the simulation job dispatcher that can manage and use multiple simulation servers at the same time to increase aggregate simulation throughput 5 The fifth component is the coordinator On every machine where a simulation server program resides a process called the coordi nator exists The coordinator process is alive as long as the simulation machine is alive When a simulation machine is powered on and brought up the coordinator running on that machine will register itself with the dispatcher to join the dispatcher s simulation machine farm Later on when its status idle or busy changes it will notify the dispatcher of its new status This enables the dispatcher to choose an avail
26. E will be replaced with the main file name For example if a simulation case s topology file is saved as test tpl then CASES will be replace with test NID will be replaced with the ID of the node to which this module is attached PID will be replaced with the ID of the port to which this module is attached When the parameter s value is evaluated variable substitutions will occur Example Suppose that the saved topology file name is testArp tpl Further suppose that an ARP module is in a node with ID being 5 and in a port with ID being 1 Suppose that a user sets the ArpTable FileName to CASE N NID _P PID arp autogendonotsave Then when this parameter is evaluated its value will become testArp N5_Pl arp The value of a parameter of this kind will always be automatically re generated by the GUI program A user cannot change its value and save it Summary In this chapter we present the concept of protocol modules and the node editor The node editor is an environment in which a user can flexibly configure the protocol stack and parameter values used inside a node The NCTUns 1 0 network simulator provides some pre built protocol modules A user can add his or her own protocol module to the node editor to test its performance 41 42 Packet Animation Player fer a user s simulation job is finished the A generated simulation results will be automatically transferred back
27. PUR Dp m on eg eee nj j Peony CET Ci ema a ST TIT 2 Choose Simulation gt Run Executing this command will cause the current simulation job to be submitted to one available simulation server managed by the dispatcher ee 1 8 l 3 When the simulation server is executing the user can see the time bar at the bottom moves The time bar will reflect the current virtual time progress of the simulation case 18 Playing Back the Packet Transfers After the simulation is finished the simulation server will send back the simulation result files to the GUI program After receiving these files the GUI program will store these files in the results directory It then automatically switches to the Play Back mode To save the network bandwidth required for trans ferring these huge file across a network especially across the slow Internet these result files are tarred using the tar command and gzipped using the gzip command into a tar ball before being sent to the GUI program This can effectively reduce the bandwidth usage by a factor of 10 or above After receiving the tar ball the GUI program needs to untar and ungzip the tar ball before using these files As such a user may experience some delay of up to a few seconds depending on the machine s speed without any progress update on the screen At this moment the user needs to be patient These files include a packet animation trace file and a
28. Sonny Snes Fee Ee SFL L PEINT ESFi T a A G H pe l o a e ARRE While the packet animation player is running the user can also launch the performance monitor to plot performance curves of logged performance metrics over time For example a TCP connection s achieved throughput or a link s utili zation The time used by the performance monitor and the packet animation player are synchronized with each other The following shows the perfor mance monitor while it is plotting a performance curve Fia Area Dii gpn 19 At this stage the whole process of using the NCTUns 1 0 network simulator to perform a simulation case study is over The user may quit the GUI program at this time while leaving the dispatcher and coordinator program running in the background Post Analyses Later on when the user wants to review the simulation results of a simulation case that has been finished before he can run up the GUI program and then open the case s topology file ee ee a ba La is m ie pig H Jamaj AA N A i ETN NE MEL TRUE mmni gal n oe 00 a0 oe a ee eae BiT The user then can switch the mode directly to the Play Back mode The GUI program then will automatically reload the simulation results the animation file and performance plotting log files Because the animation file size is usually very large this loading process may take a while After the loading is finished t
29. Such a design is to save disk space However in some normal cases result files may be generated and temporarily left on the remote simulation machine For example the results of a background job that is finished are left on the remote machine In some abnormal cases result files can also be left on the remote machine For example the GUI machine is accidentally powered off Due to these reasons the GUI program provides the File gt Remote File Management command command for a user to clean up unused files stored on a remote server If the user is using the single machine mode the user can also do the clean up without executing this command He she can directly process the files stored in the nctuns coordinator workdir located in his her home directory Background Job Management As explained before a background job is a job submitted by executing the Submit command After being submitted a background job may wait in the dispatcher s job queue waiting for an available simulation server to service it being currently executed by a simulation server or may have finished its simulation Depending on which state a background job is currently in a user can use appropriate commands to either cancel it 21 reconnect to it or retrieve its simulation results This function is provided by the File gt Background Job Management command Summary In this chapter we present how to use the NCTUns 1 0 network simul
30. The NCTUns 1 0 Network Simulator GUI User Manual Last revision date 12 10 2002 Authors Shie Yuan Wang Ao Jan Su Kuo Chiang Liao Hsi Yun Chen and Meng Chen Yu Note Because the GUI is still under constant changes the infor mation contained in this document may be out of date It is thus provided as a reference only Produced and maintained by Network and System Laboratory Department of Computer Science and Information Engineering National Chiao Tung University Taiwan Introduction elcome to the user manual of NCTUns W 1 0 a high fidelity and extensible network simulator In this introduction we will briefly introduce the capabil ities and features of NCTUns 1 0 Also to help users understand how NCTUns 1 0 works the high level structure of NCTUns 1 0 will be presented in detail Some screenshots will be presented at the end of this chapter Capabilities and Features NCTUns 1 0 uses a novel kernel reentering simulation methodology 1 As such it provides many unique advantages that cannot be achieved by traditional network simulators Support for Various Networks It can simulate wired networks with fixed nodes and point to point links It can also simulate wireless networks with mobile nodes and IEEE 802 11 b wireless network interfaces Support for Various Networking Devices It can simulate various networking devices such as Ethernet hubs switches routers hosts IEEE 802 11 wireles
31. able machine from its simulation machine farm to service a job When the coordinator receives a job from the dispatcher it forks a simulation server process to simulate the specified network and protocols It may also fork several real life application program processes specified in the job These processes are used to generate traffic in the simulated network When the simulation server process is alive the coordinator will communicate with the dispatcher and the GUI program on behalf of the simulation server process For example period ically the simulation server process needs to send the current virtual clock of the simulated network to the GUI program The is done by sending the value to the coordinator then the coordinator forwards this information to the GUI program This enables the GUI user to know the progress of the simulation During a simulation the GUI user can also on line set or get an object s value e g to query or set a switch s current switch table Message exchanges that happen between the simulation server process and the GUI program are all done via the coordinator 6 The sixth component is the kernel source patches that need to be made to the kernel source codes so that a simulation server process can run on a UNIX machine correctly 7 The seventh component is the various user level application programs Due the novel kernel reentering simulation methodology any real life existing or to be deve
32. and flexible configuration dialog box is provided for mobile nodes Under Path tab the moving speed position X Y of each turning waypoint pause time during which mobile node stays at the current turning waypoint can be configured Note that two methods of adding new waypoints are provided here Keep moving speed will calculate the arrival time of the next point by the current default speed and the distance between the current and next points On the other hand Keep arrival time will calculate the needed speed based on the arrival time of the next point and the distance between the current and next points To generate random waypoint paths two methods are provided A user can ask the GUI program to generate random waypoints on the fly He or she can also import the path from a file The user can also export the mobile node s current moving path to a file for later uses Under Single hop connectivity tab the GUI program will calculate and list when a mobile node other than the current one can and cannot be reached by the current mobile node in its single hop transmission range On the other hand under Multi hop connectivity tab the GUI will calculate and list when a mobile node other than the current one can and cannot be reached by the current mobile node in multiple hops through the help of the ad doc mode forwarding These two functions are provided for research results comparison purposes This is bec
33. ator to quickly build a simulation case The package installation process and initial environment configuration are covered in detail We also provide a quick tour to help users learn how to run up his or her simulation case right away In later chapters the functions and capabilities of the GUI program will be explained in more detail In the next chapter we will begin with the topology editor 22 Topology Editor uilding a new network topology is the B first step toward running a simulation It s an easy job through the use of the topology editor of NCTUns 1 0 The topology editor not only provides friendly GUI but also provides various attribute dialogs The following steps will show you how to build a network topology quickly Four Modes in Topology Editor Menu gt File gt Operating Mode gt Draw Topology Edit Property Run simulation Play Back P Draw Topology Run Simulaton Play Back Four modes exist in the NCTUns 1 0 network simulator A user must switch the mode at proper times to make the topology editor work correctly Mode 1 Draw Topology In this mode a user can add new nodes or links He she can also delete nodes or links Mode 2 Edit Property In this mode a user can edit the property of any node and specify the appli cation programs that will run on some particular nodes during simulation However in this mode a user can no longer change the topology of the network fixed in m
34. ause their results represents the most accurate and most optimal routing paths that only God can achieve at any time Advanced method to add Mobile Nodes Beside the simple way to click the mouse to add one mobile node at one time there are several other methods that can be used to add multiple mobile nodes at one time Insert Mobile Nodes Multiple mobile nodes that use the same protocol stack and parameter settings could be added by a user at the same time This is very convenient and efficient for a user The following is an effective way to add a large number of mobile nodes The generated mobile nodes can be placed at random positions or can be placed in an m n mobile node array It is worth reminding that before generating a large number of mobile nodes that use a protocol stack other than the default one the user better first invokes the node editor in this dialog to specify the protocol stack used by them If this operation is not done before generating a large number of nodes the user later will suffer from invoking all mobile nodes node editors to configure their protocol stacks This would be a pain Insert mobile nodes array Top lett position Jao y a0 Dimension Row f Column i Mode spacing fz00 meter rotocol stack P _ Mode editor 29 Import Export all moving paths from to file This operation saves loads mobile nodes moving paths into from a mdt file
35. can be used as an independent tool If a user wants to see the animation of a simulation case whose simulation had been finished long time ago and does not want to re run the simulation he she can switch the mode directly to mode 4 after reloading the case The user then can play the animation immediately Summary The topology editor provides a user with a friendly and easy to use interface Through this interface a user can build network topologies and specify application programs quickly A user can also easily add delete and configure different network devices Node Editor he node editor provides a convenient T environment for flexibly configuring the protocol modules used inside a network node By using this tool a user can easily add delete or replace a module with his her own module to test the performance of a new protocol Protocol Module Concept A protocol module usually implements a particular protocol such as ARP or a particular function such as the FIFO packet scheduling disci pline In the node editor all modules that are grouped in the same module group displayed at the top of the node editor share similar properties For example in the 802 11 MAC group we may have one module called 802 1 IMAC while another may be called my802 1 IMAC The NCTUns 1 0 network simulator provides several pre developed protocol modules Users can add new protocol modules to the node editor or replace some e
36. control the execution of the simulation For a session to re own the GUI program the user must execute the Simulation gt Reconnect command After the Simulation gt Disconnect command is executed an input session name dialog will show up and prompt the user to input a session name see Fig 6 After the session name is entered all information about this session is automatically recorded by both the dispatcher and the GUI programs The simulation currently running on the server side will continue its execution However the user now is free to use the GUI program to handle another simulation case Due to this feature a user can run as many simulations as he she wants at the same time provided that there are enough simulation servers in the server farm To avoid session name conflicts a user should give each session a unique name lt Session name Session name Hella MCTUns Cancel Fig 6 The Disconnect dialog box Reconnect A user can reconnect a disconnected session by executing the Simulation gt Reconnect gt Session Name command see Fig 7 The session name chosen here is the name that the user entered when he she disconnected the session Fig 6 After the user reconnects a session one of two different cases may happen In the first case the simulation is still running Every soon the user will see the time bar resumes ticking as if the user have never disconnected the simulation In t
37. d by the dispatcher to that server to run the simulation lt Submit job as a background Background Job Mame Job After a background job is submitted you can View its status and progress by using the File Backgroaund Job Management command cece Fig 8 Submit a background job e Background Job Management After several background jobs are submitted a user can manage these background jobs through the background job management window see Fig 9 To pop up the window a user can execute the File gt Background Job Management command In the window a user can easily check the current status of his her background jobs To get the most updated information a user can press the Refresh button on the upper left To close the window a user can press the Cancel button on the upper right A background job may be in one of three different possible statuses First the simulation job is finished In this case the user can click on the job name and then press the Retrieve button at the button of the window to transfer the log files back to the GUI program Second the job is currently running on a simulation server In this case the user can reconnect abort or stop the simulation by pressing the corresponding buttons These operations do the same thing as those described in previous sections Note that internally a backgound job is processed like a disconnected session As such it is possible for the GUI program to r
38. d increase his her productivity Yet another task that is automatically done by the GUI program is that the GUI program will force the switch module used inside an access point to use the Run_Learning_Bridge mode despite that the user may configure it to use the Build in Advance These two modes affect how the switch forwarding table used inside the switch module is built The first method is a dynamic method while the second is a static method The second method works very well for fixed networks However in mobile networks where mobile nodes move around and change their associated access points constantly the static method will no longer work correctly To avoid the user to suffer from unexpected wrong simulation behavior and results the GUI program thus automatically forces the switch module inside all access points to use the dynamic Run_Learning_Bridge method to dynamically build their switch forwarding tables 14 So in the future when you see that the GUI program does not honor your settings for some devices or protocol modules do not be surprised You know that the GUI program is doing this for your good Editing network nodes properties can be done in two ways In the first way a user can use the mouse to double click a network node s icon A dialog box will soon appear in which a user can set parameter values or option values The following shows the results of double clicking the router
39. describe it Suppose that we want to replace the built in ARP module with ours then we can use the following steps to do it Define a module s Parameters To let the node editor know that a new module has been added to the node editor the user must add and place the definition of the module into a module description file mdf cfg To understand the detailed format and meanings of the module description file readers should refer to that file stored in usr local nctuns etc and the NCTUns 1 0 Module Writer Manual 1 parameter attribute local means that this parameter is used only in this module Its value if updated should not be copied to other modules of the same kind global means that this parameter s value if updated should be automatically copied to all other modules in the network of the same kind autogen means that the parameter s value will be automatically generated and determined by the GUI program Examples include the IP and MAC addresses autogendonotsave this is very similar to autogen except that there will be variable substi tutions when evaluating the parameter s value Beside since its value is automatically generated based on a formula any change made by the user will not be saved 2 CASE NID PID variable substi tution Normally an autogendonotsave parameter s value is a formula consisting of the following variables CAS
40. dispatcher and coordinator Their names are mdf cfg dispatcher cfg and coordinator cfg respec tively 4 usr local nctuns BMP This directory stores the icon bmp files used by the GUI program These icon files are used for displaying various devices icons and control buttons 5 usr local nctuns lib This directory stores the libraries needed by the GUI program and simulation engine For example Qt 3 0 5 library and TCL 8 3 library need to be installed for the GUI program and the simulation engine respectively Installation Procedure Before starting the installation a user should carefully read the README and INSTALL files first Both of these two files contain important installation information A user then runs the install sh shell script This script will make changes to the kernel source code of the simulation machine and then re build the kernel It will also build all executable programs and copy them to their default directories In addition it will create 4 096 tunnel special files tunnel interfaces in dev These steps may take some time After these tasks are done the machine must be rebooted to use the new kernel Next time when the machine is boot up again the whole instal lation is finished and can be viewed as successful After the installation before using the GUI program the first time the user should create two directories in his or her home directo
41. e nodes in a mobile ad hoc network simulation case cannot excced 4 096 This is because each mobile node uses a layer 3 interface The used subnet number starts from 1 and automatically grows upward The used host number on a subnet also starts from 1 and automatically grows upward If there are ad hoc mobile nodes in the network the subnet ID 1 is reserved and used for the ad hoc subnet formed by these ad hoc mobile nodes In such a case the subnet number used for fixed subnets will start from 2 On the other hand if there is no ad hoc mobile nodes in the network the subnet number used for fixed subnets will start from 1 Note that the GUI program only automatically generate and assign IP addresses to ad hoc mobile nodes te and hosts and routers on the fixed network For infrastructure mobile nodes alll the GUI program does not automatically generate and assign IP addresses to them The reason is that an infrastructure mobile node needs to use an access point to connect itself to the fixed network To be able to successfully send and receive packets to and from the fixed network the infrastructure mobile node needs to use an IP address whose subnet ID is the ID of the subnet that the access point belongs to However during the automatic IP generation process the GUI program does not know which subnet the user would like an infrastructure mobile node to belong to As such the GUI program cannot intelligently generate and
42. e simulation is finished To do so the user can execute the Simulation gt Stop command The simulation engine and traffic generator processes will be stopped and killed immediately The current results will be trans ferred back to the GUI program for further analyses Abort a Simulation When a user aborts the simulation by executing the Simulation gt Abort command the simulation engine and all traffic generator processes will be killed immediately The current results will be completely deleted without being transferred back to the GUI program It is recommended that a user either aborts or stops a running simulation before quiting the GUI program Otherwise the currently running simulation will keep running and full results will be generated on the disk This will only unnecessarily waste CPU cycle and disk space resources Session Management Most modern GUI program uses the MDI multiple document interfaces design However the NCTUns GUI program uses the SDI single document interface design To run multiple simulations concurrently using a single NCTUns GUI program the GUI program uses a session management mechanism which is discussed below Disconnect After a simulation is run a user can make it as a session by executing the Simulation gt Disconnect command A session is defined to be a simulation job that currently does not own the GUI program As such the user can no longer use the GUI program to
43. econnect to a background job Third the job is still in the job queue waiting for execution The user can delete it from the job queue if he she no longer wants the job to be run This operation can be done by pressing the Delete button Note that a user has to select a background job from the table before he she can perform any management operation on it The command buttons that are allowed for the selected job will be enabled Background Job Management Current Waiting Jobs 0 Refresh i FINISHED Fri Nov 15 20 56 21 2002 Fri Nov 15 20 56 21 2002 Fri Nov 15 21 04 46 2002 1037364981 999 RUNNING Fri Nov 15 20 56 40 2002 Fri Nov 15 20 57 37 2002 1037365000 999 RUNNING Fri Nov 15 20 56 47 2002 Fri Nov 15 21 04 47 2002 1037365007 999 WAITING Fri Noy 15 21 05 08 2002 1037365508 999 Fig 9 The Background Job Management window 37 Remote File Management e Remote File Management The remote file management utility is a conve nient tool for a user to manage his her files that are generated and stored on a remote server Note that when a user is using the single machine mode of the simulator generated files actually are stored on the local machine s disk However the remote file management utility can still be used correctly To pop up the remote file management window a user can execute the File gt Remote File Management see Fig 10 command The file management window is like a file browser on Wi
44. eft button on top of the router 8 Add the other two links in the same way Now our simple topology is done im a FE irr g en ji ee Py Te TST a A HE a g 9 Remember to save this network topology by choosing File gt Save For this simple case we will save the topology file as test tpl Fie Ear Yra Tok Brine ap Dgan Hin Hal Open Soe AE Erri Ga aide pansy i EAA E Ei It is not necessary to save the network topology into a file in this mode A user can also save it in the Edit Property mode Depending on in which mode a network topology file was saved when the file is opened again its current mode will be automatically set to the mode when it was saved Editing Nodes Properties A network node device may have many param eters to set For example we may want to set the maximum queue length of a FIFO queue used inside a network interface For another example we may want to specify that some application programs traffic generators run on some hosts or routers to generate network traffic Before a user can start editing the properties of network nodes he or she should switch the mode from the Draw Topology to Edit Property mode In this mode topology changes can no longer be made That is a user cannot add or delete network nodes or links at this time If the user has not given a name to this simulation case the GUI program will pop up a dialog at
45. f infrastructure mode mobile nodes with their IP addresses automatically assigned Note that when you want to automatically generate IP addresses for infrastructure mode mobile nodes the total number of these nodes must not exceed 255 Otherwise the 255 IP addresses on the specified subnet will be used up and will not be sufficient for all of these nodes Remove All Moving Paths Executing this command can delete all mobile nodes moving paths This will give the user a clean working area to start with Enter See Movement Mode When studying a mobile wireless network problem a user usually needs to specify many mobile nodes moving paths in such a way that their wireless signals can reach or cannot reach each other at particular times or at particular locations To help a user do this tedious job the ruler tool is provided by which a user can measure the distance between two nodes To further help the user the GUI program provides the See Mobile Node Movement mode In this mode mobile nodes will move along their moving paths over time and a red line connectivity indication will show up between two mobile nodes whenever their wireless signals can reach each other This way the user can easily see whether his or her mobile path configurations really match his or her expectations To enter this mode a user can simple check this mode Then the user can use the control buttons of the time bar located at the bot
46. he second case the simulation is already finished before the user reconnects it In this case file transfers will automatically be started to transfer the result and log files back to the GUI program 0 0 0 ee A A Ol Fig 7 The Reconnect session dialog box 55 56 Background Job Management Background job management is a useful facility that allows a user to submit several simulation jobs almost at the same time A background job is a simulation job that does not intend to use the GUI program After a simulation is submitted as a background job it will be sent to the dispatcher program immediately and the GUI can be immedi ately used by other simulation cases Thus a user can submit a background job without waiting for the job to finish It is very useful when running a time consuming network simulation e Submit a Background Job It takes three easy steps o submit a simulation as a background job First a user needs to open edit a network topology and switch to the Run Simulation mode see Fig 2 Second the user then executes the Simulation gt Submit command Third when the submit dialog box shows up the user then enters a desired job name and press the Submit button see Fig 8 The job will then be sent to the dispatcher and stored in the dispatcher s job queue Immediately when any simulation server in the server farm is available the first background job in the job queue will be dispatche
47. he user can use the control buttons located at the bottom of the screen to view the animation just like what he she would do when a simulation job is done 20 Simulation commands After running up a simulation and before it is finished a user can have control over its execution Job control commands are grouped in Menu gt Simulation The following will explain the meaning of each job control command e Run Start to run the simulation e Pause Pause the currently running simulation e Continue Continue the simulation that was just paused e Stop Stop the currently running simulation e Abort Abort the currently running simulation The difference between Stop and Abort is that a stopped simulation job s results will be transferred back to the GUI program However an aborted simulation job s results will not be transferred back They will be immediately deleted on the simulation server to save disk space Reconnect the Reconnect command can be executed to reconnect to a simulation job that was previously disconnected All disconnected jobs that have not finished their simulations or have finished their simulations but their results have not been retrieved back to the GUI program by the user will appear in a session table When executing the Reconnect command a user can choose a disconnected job to reconnect from this session table Disconnect Disconnect the GUI from the currently running simulat
48. his case the user will see the time bar located on the bottom left start ticking In the second outcome a Log in Failed message box will be shown up see Fig 4 which means that the provided user name and password are wrong and thus do not allow the user to log in to the local machine In the third outcome a No idle server message box shows up see Fig 5 This means that currenly all of the simulation servers are all busy executing simulation cases The user can try to re run this simulation case at a later time He she can also choose to submit it as a background job which will then be queued at the dispacther waiting for its turn NcTuUns A Login Failed Fig 4 The Login Failed message dialog 53 54 NCTUns AA Mo Idle Server Fig 5 The No Idle Server message dialog box e Pause a Simulation When a simulation is running a user can pause it by executing the Simulation gt Pause command The simulation engine process and all traffic generator processes will then be paused immedi ately e Resume a Simulation A user can resume a paused simulation job by executing the Simulation gt Continue command The simulation engine process and all traffic generator processes will be waked up and continue the job from the point where you paused 1t e Stop a Simulation Sometimes a simulation run may take too long and a user may thus want to retrieve the current results before th
49. his program is also located in usr local nctuns bin Draw a Topology After the starting screen of the NCTUns 1 0 disap pears a user will be presented a working window as shown below E pii jiii e oe he khh 9 et oer es C ee eet oa non Gt AA dP a Rie Oe a fot The initial working window To edit a new network topology a user can perform the following steps 1 Choose File gt Operating Mode and make sure the Draw Topology mode is checked Actually this is the default mode which the NCTUns 1 0 will be in when it is launched 10 iw Draw Topology Run Simulaton Play Back It is important to note that only in this mode can a user draw a new network topology structure or change an existing simulation case s topology When a user switches the mode to the next mode Edit Property the simulation case s network topology can no longer be changed Instead only devices properties attributes can be changed at this time The GUI program enforces this rule because when the mode is switched to the Edit Property mode for the user s convenience it will automatically generate many settings e g an layer 3 interface s IP and MAC addresses Since the correctness of these settings depends on the current network topology if the network topology gets changed these settings will become wrong If after editing some devices properties the user would like to change
50. ight 2002 Network and System Laboratory Department of Computer Science and Information Enginccring National Chiao Tung University Taiwan All rights reserved Fig 1 The starting screen of the NCTUNS 1 0 Topology Editor The topology editor provides a convenient and intuitive way to graphically construct a network topology A constructed network can be a fixed wired network or a mobile wireless network Due to a user friendly design all GUI operations can be done easily and intuitively Sie tem jmp prem r r Te CIFTET EEE Sy 5 ry is ls sma SS A HP j ee Fig 2 The topology editor of the NCTUns 1 0 Attribute Dialog Box A network device node may have many attributes Setting and modifying the attributes of a network node can be easily done Just double clicking the icon of the network node An attribute dialog box will pop up You then can set the device s attributes in the dialog box O OB OO ima maan A A e jl a e ae Fig 3 A popped up attribute dialog box in the NCTUns 1 0 Performance Monitor The performance monitor can easily and graphi cally generate and display the plots of some monitored performance metrics over time Examples include a link s utilization or a TCP connection s achieved throughput Because the format of its input data file uses the general two column x y format and the data is in plain text the performance monitor can be used as an i
51. in the same window It is particularly useful for comparing different performance metrics that are collected at the same time Menu gt Color e Background This option is to select a color from the palette and set it as the background color of the current graph window e Axis This option is to select a color from the palette and set it as the color of axes of the current graph window 49 e Grid This option is to select a color from the palette and set it as the color of grids of the current graph window Graph This option is a sub menu from which users can choose a different graph source to display Then the user can select a color from the palette and set it as the color of the performance curve in the current graph window Menu gt Option eneral 5 etting Global setting Graph Mode e General Setting Fara u l Ta a ea TA f g Ti U pka FL F g f p Tem a name a 4 Maba ed SEE L E ika bih in ieii B p Ee Ppetereree Seep ri E Linea U Soe are i coe a e pac Graph Title This field sets the title of the graph Y label This field sets the label of the y axis 50 X label This field sets the label of the x axis Note that a performance curve s label and color can be easily set by double clicking the curve s label located at the upper right corner For example a user can double click the graph X default curve label Y tics This field sets the interval of the
52. ink s bandwidth signal propagation delay bit error rate BER and down time periods for each direction of the link The picture below shows the link property editing dialog box The link property setting dialog The down time period information will be propa gated to and be set in the Phy or Wphy module of the two nodes that connect to this link Therefore the down time periods set in an interface s Phy or Wphy module actually is the union of the down time of the node to which this interface belongs and the down time of the link to which this interface connects Beside the down time information other attributes of a link are also propagated to the appropriate modules of the two nodes that connect to this link For example the bandwidth signal propagation delay and BER are all propagated and set in these Phy or Wphy modules It is worth noting that this automatic link parameter propagation process will override the settings specified by the user in the node editor for these Phy or Wphy modules The GUI program adopts this design because it is more intuitive and natural to set a link s attributes by double clicking it Individually invoking the node editors of the two nodes that are at the ends of a link to set the link parameters is less intuitive and natural 25 26 Command console is equipped by Host Router and Mobile Nodes This function is enabled only when a simulation is currently running A user can
53. ion job The GUI now can be used to service another simulation job A disconnected simulation job will be given a session name and stored in a session table e Submit Submit a job to the dispatcher without first running it in the GUI then immediately disconnecting it Its net effect is the same as first running a simulation job and then immediately disconnect the GUI program from it A job submitted in this way is called a background job It does not need the GUI s support or occupy the GUI while its simulation is ongoing A background job may wait in the dispatcher s job queue if currently there is no available simulation server to service this job Whenever a Simulation server becomes available on behalf of the GUI program that submitted this background job the dispatcher will automati cally start the background job s execution on that simulation server Remote File Management If the GUI user uses the NCTUns 1 0 network simulator s multiple machine mode e g submitting his or her jobs to the simulation service center located at NCTU since the machine on which the GUI program runs is different from the machine on which the simulation server running this simulation runs the generated simulation results will temporarily be stored on the remote simulation server By default the files generated on a simulation server will be automatically deleted after they are automatically transferred back to the GUI program
54. is 9 800 for the dispatcher to receive messages sent from GUI program s These default settings can be found and changed in the dispatcher cfg file which is located in usr local nctuns etc 3 Start up the coordinator Now a user can run up the coordinator which is located in usr local nctuns bin Since the coordinator needs to register itself with the dispatcher we must let the coordinator know the port used by the dispatcher to receive regis tration messages It is 9 810 in the above example This port information is specified and can be changed in the coordinator cfg file located in usr local nctuns etc The second important information for the coordi nator to know is the IP address used by the dispatcher If the user is using the single machine mode since the dispatcher and the coordinator are running on the same machine the IP address can be specified as 127 0 0 1 which is the IP address of the look back network interface On the other hand if a user is using the multiple machine mode and the dispatcher is running on a remote machcine the IP address specified should be the IP address of that remote machine If the settings specified in the coordinator cfg file are all correct then the user can start up the coordinator now 4 Start up the nctunsclient After all of the above steps are successfully done now the user should be able to launch the NCTUns 1 0 GUI program called nctunsclient success fully T
55. ll log files that the user specified to generate while in the Edit Property mode The packet animation trace file can be replayed later by the packet animation player while the performance curve of these log files can be plotted by the performance monitor Details about the animation player and the performance monitor will be explained in later chapters For this simple case the packet animation trace file is named test ptr which uses the main file name of our topology file test tpl The ptr is a logged packet transfer trace file Its animation can be played by the animation player at any specified speed When the GUI program has untarred and ungzipped the ptr animation log file it automati cally switches to the Play Back mode In this mode the control buttons of the time bar located at the bottom of the screen can be used to play stop pause continue jump forward jump backward intelligently jump forward the animation The user can also directly move the time knot to his her desired time to see the packet transfers occurring at that time For example the user can left click the start icon gt of the time bar located at the bottom The animation player then will start playing the recorded packet animation The following shows these control buttons Q AJM gt Im p The following shows the animation player when it is playing an animation log file Lisia ee Seeder ioe he ies il op Bi Toa
56. loped application program can directly run on a simulated network to generate network traffic 8 The eighth component is the various user level daemons that are run for the whole simulation system For example the NCTUns 1 0 provide RIP and OSPF routing daemons By running these daemons the routing entries needed for a simulated network can be constructed automati cally Due to this distributed design a remote user can submit his or her simulation job to a specified dispatcher and the dispatcher will then forward the job to an available simulation server for execution The server running the simulation engine will process simulate the job and later return the results back to the remote GUI program for further analyses This scheme can easily support the server farm model in which multiple simulation jobs are performed in parallel on different server machines Compared to the above described multiple machine mode there is also a single machine mode In such a mode all of these components are installed on a single machine Although in this mode simulations cannot be run concurrently since most users have only one machine to use this mode may be the best mode for them Screen Shots To give users a quick idea about what the multi purpose GUI environment may look like some screen shots are presented below Starting Screen Every time when you launch the GUI program you will see this screen popped up Copyr
57. nd stcp are the pre installed application programs that greedily send and greedily receive TCP data respectively Also we assume that the receiving node has an assigned IP address of 1 0 1 2 and the rtcp program binds its receiving socket on port 8000 From the above example we see that the specified invocation commands are exactly the same as a user would type in a UNIX terminal to invoke run up these application programs by himself herself For a large network that has hundreds or thousands of nodes hosts routers or mobile nodes the user can use the GUI s Tools Insert Applications command to read in a traffic config uration file tfc The format of a tfc file is the same as the tfc file exported by the GUI program for a simulation case when it switches its mode to Run Simulation Normally a tfc file used in such a case is generated by a script or a program written by the user Each traffic generator 1 e application program command string specified in the tfc file will be put to the Applications tab of the specified node This operation can greatly save a lot time because now the user need not invoke each node s dialog box individually The following shows where this command is located Mobile nodes Insert Spplications Plot Graph Running the simulation When a user finishes editing the properties of network nodes and setting up application programs he or she can start to run the simulati
58. ndependent tool that is it can be used to plot graphs from data generated by other application programs pe aree e a 7i Ee im Pa a m u cone eee D ae E E l D 4 eon ba thee PETIT TTT rel hae ee 19 od il Fig 4 The performance monitor of the NCTUns 1 0 Node Editor The node editor provides a convenient environment in which a user can flexibly configure the protocol modules used inside a network node By using this tool a user can easily add delete or replace a module with his her own module This capability enables a user to easily test the performance of a new protocol Regarding how to add a new protocol module to the node editor 1 e to let it know you have added a new protocol module to the simulation engine readers should refer to the NCTUns 1 0 module write manual 4 p al le Peek ar l TERN Fig 5 The node editor of the NCTUns 1 0 Packet Animation Player By using the packet animation player a logged packet transfer trace can be replayed at a specified speed Both wired and wireless networks are supported This capability is very useful because it can help a researcher visually debug and test the behavior of a network protocol It is also very useful for educational purposes because students now can see how a protocol behaves ta Bie Teak jnn Soar Few Hip Bee sete wv SN d Ns EA A E r AA A A e m p
59. ndows operating systems A user can change to a directory by double clicking on the desired directory name To transfer a file from the remote machine to the local machine a user can simply click on the file and press the Get button A user should specify the local directory to store downloaded files This can be done by editing the Dir Name text field To delete a file on the remote server a user can click on the file and press the Delete button Finally a user can close the window by pressing the Cancel button Remote Files File Type Last modifed a directory Tue Oct 29 20 32 25 2002 L netuns 1035841954 job directory Tue Oct 29 22 07 17 2002 J netuns 1035854084 job 3584 directory Wed Oct 30 01 29 21 2002 C netuns 1035874066 job 3584 directory Tue Oct 29 23 02 42 2002 C netuns 1035877820 job 5120 directory Wed Oct 30 00 04 59 2002 J netuns 1035893672 job 3584 directory Wed Oct 30 04 29 27 2002 C netuns 1035895062 job 3584 directory Wed Oct 30 04 52 37 2002 C netuns 1035896875 job 10240 directory Wed Oct 30 05 22 55 2002 C nctuns 1035949585 job 1024 directory Thu Oct 31 04 00 56 2002 J netuns 1035966595 job 1024 directory Thu Oct 31 01 17 50 2002 C netuns 1036019966 job 6192 directory Thu Oct 31 23 45 04 2002 A netine1N3RNP5R1 7inh A197 diractnry Eri Mau 1 01 11 27 20N x File Name fhctuns 1035841954 job Cance Dir Name fimp Delete Fig 10 The Remote File Management window Summary This chapter is about
60. ng gt Mobile node gt show mobile node flag This command can turn on off a flag to display not to display the mobile node s icon Doing this can clean the working area Menu gt Setting gt connectivity color This command sets the color used by the connec tivity indication line Each different frequency channel can use a different color During a simulation different mobile nodes may be configured to use different frequency channels Using different colors for different frequency channels enables a user to easily distinguish them Menu gt Setting gt wireless Frame color This command sets the colors used by various wireless frames Each different frequency channel can have a different color scheme This is useful when the packet animation player is running File manipulation Menu gt File gt New Close the current simulation case and clear the working area for a new case Menu gt File gt Open Save Save as Save the current simulation case s topology and node configurations into the tpl and tcl file respectively This case can later be reloaded Menu gt File gt Print to File The graph shown on the screen can be saved to a bmp file for printing purposes Menu gt File gt Remote File Management Files generated at remote simulation servers can be retrieved or deleted by this function Menu gt File gt Background Job Management Any background job submitted to the dispatcher can be manipulated
61. o make reports 51 32 Inter Process Communications nter process communication enables the l NCTUns GUI to connect to both the dispatcher and the simulation engine We detail how to use the facilities provided by inter process communication in this chapter Preparation e Connect to the Dispatcher Before submitting a job to the simulation enigne a user should check whether he she has correctly set the information about the dispatcher A user can do this job by executing the Setting gt Dispatcher command The configuration dialog box is shown in Fig 1 Preference Job dispatcher IP address he7 fo fp ft Port faaoo User information User name nctuns Fig 1 The dispatcher dialog box If the user is running a simulation engine on the local machine the IP address can be 127 0 0 1 which normally is the IP address assigned to the loopback interface lo0 Of course if the machine has an IP address say 140 113 1 1 assigned to one of its interfaces that IP address can be typed in here The user name and password should be the same ones as those that the user uses to log in to the local machine If the user would like to use the simulation service center located at the Network and System Lab NSL NCTU he she needs to obtain his her username password by registering with the NCTUns web site at http NSL csie nctu edu tw nctuns html The default port number is 9800 A user can modify this number by
62. obile node has its own moving path To specify a mobile node s moving path a user can first click the icon RA on the tool bar He she then clicks the mobile node and start dragging and dropping repeatedly to construct its whole moving path This operation continues until the user clicks the mouse right button 23 24 A moving path is composed of a sequence of turning points and segments After a moving path is constructed any of its turning points can be moved to any place to adjust the shape of the path Each turning point is represented by a grey dashed square box and contains the X loc Y loc arrival time pause time speed to the next point infor mation This information can be changed by double clicking the box When a mobile node is moving from one point to the next point 1 e moving on a segment its moving speed is fixed There are some other useful tools on the tool bar They are select l delete X ruler zoom in and zoom out er ey The operation of the ruler is the same as setting up a link between two device nodes A message box will show up telling the distance in meter between the selected two nodes It is primarily used to place mobile nodes and access points at proper locations so that their wireless signals can or cannot reach each other as planned Editing the attributes of Nodes After nodes are added a user can enter mode 2 to set the detailed attributes of any node by double clicking i
63. ode 1 Mode 3 Run simulation In this mode a user can run pause continue stop abort disconnect reconne ct a simulation in this mode No simulation settings can be changed in this mode Mode 4 Play Back After a simulation is finished the ptr packet animation trace file will be automatically sent back to the GUI program The GUI program will then automatically enter into mode 4 Adding Nodes with Tool Bar There are several types of network device icons on the tool bar including host hub router switch ral access point mobile node ad hoc mode we and mobile node infra structure mode a A user could choose a device for insertion by clicking the mouse left button on it He she then can move the mouse cursor to a location in the working area and then click again to place the chosen device on the current position of the cursor The following shows the topology after a user has put some node in the working area o gt ra amp Of course a network topology consists of not only nodes but also links between them Links also can be added to the network topology very easily A user can click the link icon a move the cursor to one device node click the device node to fix one end of the link drag the link to another device node then click the selected node to fix the other end of the link The user can see that a straight line between the two selected nodes is established The following shows the
64. on In order to do so the user must switch the mode explicitly from Edit Property to Run Simulation Entering this mode indicates that no more changes can should be made to the simulation case which is reasonable The simulation is about to be started At this moment of course any of its settings should be fixed 16 Whenever the mode is switched into the Run Simulation mode the simulation files that describe the simulation case will be exported These simulation files will be transferred to the remote or local simulation server for it to execute the simulation These files are stored in the mainFileName sim directory where mainFileName is the name of this simulation case chosen in the Draw Topology mode For example if the topology file is named test tpl these exported simulation files are stored in a directory named test sim Among these exported files the test tcl file stores the configuration of every node s protocol stack This file is very important and should always goes with the test tpl file For example if a user wants to move or copy a simulation case from one place to another place in a file system he she must move or copy the tpl and tcl files at the same time Otherwise the moved or copied simulation case cannot be successfully reloaded For this particular example he she must move test tpl and test sim test tcl at the same time Beside the
65. pec tively In the following we will explain each of these subdirectories 1 usr local nctuns bin This directory stores executable programs of the GUI program dispatcher coordinator and the simulation engine Their names are nctun sclient dispatcher coordinator and nctunsse respectively 2 usr local nctuns tools This directory stores executable programs of various applications and tools pre installed by the NCTUns 1 0 network simulator For example tcpdump stg 99 66 99 66 99 66 currently step rtcp ttep ripd ospfd nctunsTcsh script 66 99 66 99 99 rtg tsetenv ifconfig are supported Due to the use of a novel kernel reentering simulation methodology 1 one unique advantage provided by the NCTUns 1 0 is that any real life application program can run on a simulated network to generate traffic During simulation in order to run up an appli cation program that is not pre installed in this directory the user must first copy that program into this subdirectory i e usr local nctuns tools so that the NCTUns 1 0 can find it during simulation Detailed information on how to specify which application programs should be run on which nodes in the GUI program is presented in the Topology Editor Chapter 3 usr local nctuns etc This directory stores the configuration files needed by the GUI program
66. program as long as the log file uses the common X Y format Operations for Performance Monitor Many operations are provided in the menu of the performance monitor window Here we will give a full description Menu gt File snapshot onapshot All uit e New Open a new graph window Up to six graph windows can be shown on the screen at the same time 48 e Open This option is to open a desired log file as a graph source A graph source will then be associated with a graph window e Snapshot Graph 1 Graph z Graph 3 Graph 4 Graph 3 This option is to pop up the snapshot window for capturing the content that is currently displayed in the window This window will show the captured snapshot Pressing Re snapshot button will re capture the performance curve that is being displayed Pressing Save button will save the snapshot as an image file of the bmp type Pressing Cancel will quit the window Snapshot All This option will take snapshots of all existing graph windows The feature is very useful for comparing different performance metrics results e Quit This option will quit the current graph window Menu gt Window Add Remove Graph e Add Remove Graph This option is a sub menu from which a user can choose different graph sources Selected graph sources are headed with check marks Users can use this option to display more than one graph sources
67. ral control buttons The Cancel button discards all changes that have been made to this node s protocol modules The OK button accepts all of the changes made so far The Undo button removes the effect of the last delete operation Note only the LAST delete operation can be undone The Redraw button re layouts the protocol modules so that they look nice when shown on the screen This is particular useful after a user performs the insert or delete operation The Copy To All Port CTAP button copies the values of the currently selected module s param eters to the same modules in all ports of this node The Copy To All Node CTAN button does the similar job However it copies the values to the same modules in all ports of all nodes in the whole network The X button means delete After pressing this button now the node editor s mode enters the delete mode From now on whenever the user uses the mouse to left click a module or a link that object will be deleted The Arrow button means select After pressing this button now the node editor s mode enters the select mode From now on the user can move a protocol module to any desired place The user can also choose a module from the top module groups insert and place it in the middle working area Operations Insert Delete Replace a module As an example here we demonstrate how to replace a FIFO module with
68. ry The first directory is nctuns in which several GUI temporary files will be stored The second is nctuns etc in which the GUI program s preference setting file will be stored Note that the creation of these two directories should be done only once More detailed and up to date installation and usage information can be found in the package of the NCTUns 1 0 network simulator A Quick Tour Setting up the environment Suppose that a user uses the single machine mode of the NCTUns 1 0 before he she starts the GUI program he she needs to do three things The first is setting environment variables The second is Starting up the dispatcher and the last is starting up the coordinator 1 Set up environment variables Before a user can run up the dispatcher coordi nator or nctuns GUI program he she must first set up the NCTUNSHOME envronment variable To do this a user can type in and execute the setenv NCTUNSHOME usr local nctuns shell command in his her terminal window e xterm For the GUI program an additional environment variable LD_LIBRARY_PATH must be set The following shell command setenv LD_LIBRARY_PATH usr local nctuns lib can be executed to do this job 2 Start up the dispatcher Now a user can run up the dispatcher which is located in usr local nctuns bin The default port number used by the dispatcher to receive messages sent from coordinator program s is 9 810 It
69. s access points and interfaces etc Support for Various Network Protocols It can simulate various protocols such as IEEE 802 3 CSMA CD MAC IEEE 802 11 b CSMA CA MAC learning bridge spanning tree IP RIP OSPF UDP TCP HTTP FTP Telnet etc Application Compatibility 1 All real life existing or to be developed UNIX application programs can be run on a simulated network to generate network traffic 2 All real life existing UNIX network configu ration tools e g route ifconfig netstat or performance monitoring tools e g tcpdump traceroute can be run on a simulated network to configure or monitor the simulated network User Friendliness It provides an integrated and professional GUI environment in which users can easily conduct network simulations As a powerful tool the GUI is capable of e drawing network topologies e configuring the protocol modules used inside a node e specifying the moving path of mobile nodes e plotting network performance graphs e playing back the animation of a logged packet transfer trace e more Open System Architecture By using a set of module APIs that are provided by the simulation engine a protocol module developer can easily implement his or her own protocol and integrate it into the simulation engine Details about adding a new protocol module to the simulation engine is presented in the NCTUns 1 0 module write manual High Level Structure NCTUns 1
70. spatcher The user should configure these settings by invoking the Setting gt Dispatcher command The following shows the popped up dialog box di dispatcher IP address flan E Pia E Pont fom Leer inim ation Leer nare imul ETES pea Enad address i The default port number is 9 800 If the user is using the single machine mode the IP address can Cancel be specified as 127 0 0 1 The user name and password must be valid For the single machine mode they are the user s account on this local machine For the multiple machine mode they are the user s account on the remote dispatcher machine During simulation 1 e when the simulation is not finished yet the result files generated by the simulation engine are stored in the home directory of the provided user account Hence this infor mation must be correct and valid Otherwise the GUI program will crash due to access permission error Specifying the email address is not necessary However if this information is provided a remote dispatcher will send back a notice email to the user when the user s background job is finished in its simulation service center 17 Since we have made a complete simulation case and we are sure that the dispatcher and coordinator are ready we can now proceed to run the simulation 1 Choose File gt Operation Mode And check Run Simulation F Ph Ea ee ee a H i ra A R A fm e e Pi iH F ed DH Fiji
71. tom of the screen to control the progress To leave this mode the user can simply check this mode again When a mobile node starts moving in this mode a green box will appear on the screen to indicate its current location To have a clear view of the field the user can choose not to display these mobile nodes moving paths and their icons How to change these settings are explained below Change View of the Mobile Node Menu gt Setting gt Mobile node gt show moving path flag This command can turn on off a flag to display not to display the moving path of each mobile node Menu gt Setting gt Mobile node gt show transmission range flag This command can turn on off a flag to display not to display the transmission range the default value is 250 meters of each mobile node E Menu gt Setting gt Mobile node gt show interference range flag 31 This command can turn on off a flag to display not to display the interference range the default value is 550 meters of each mobile node HEE Hep e E F eo 2 oe eee AA fe he a a S Se a Hea Menu gt Setting gt Mobile node gt show connectivity flag This command can turn on off a flag to display not to display the connectivity indication A shown red line between two nodes is the connectivity indication When a red line is shown it means that the two nodes connected by it are in the trans mission range of each other 32 Menu gt Setti
72. topology after the user has placed several links in the working area to connect these nodes together When nodes and links are added or deleted to form a network topology a node s ID and the ID of its ports interfaces will be automatically assigned and adjusted by the GUI program The GUI program will re number each node s ID when any node is deleted from the topology to make sure that node IDs are continuously numbered For a node when one of its link is deleted the GUI program will also re number the ID of all of its ports interface to make sure that port IDs start at 1 and are continuously numbered inside a node To clearly see where a mobile node has moved to a node s ID is displayed next to its icon on the screen at all time A port interface of a node is represented by a blue box When the user switches the mode to the Edit Property mode a layer 3 port s IP and MAC addresses will be automati cally generated and assigned In this mode if the user moves the mouse cursor and place it over the blue box for a while the port s information port ID and IP address will be shown on the screen Note that the information shown for a layer 1 port e g a hub port or layer 2 port e g a switch port contains only the port ID information This because these ports do not have IP addresses assigned to them The above picture shows that each interface is represented by a blue box In areal network environment a m
73. ts icon Here are some common attribute tabs shared by many kinds of devices Host ID f Mame Host Hri iD ra gap del Bean fra Pad iy D mish Under the Application tab a user can specify which application program to run on this node He she can put the command string into the command field In addition to the command string the start stop time and argument of the specified command program can also be set Hipi iE Aes fi Ap FE Open E F Eri rt Erel pii PEI Soe DP EEH About the Down time tab a user can set the durations during which the node is down cannot send or receive any packet The down time periods configured here will be propagated and set in the Phy or WPhy module of each of the node s interface This is because the Phy or Wphy modules are the right place to disable or enable the transmission or reception of packets To turn down only an interface but not all inter faces of a node a user can open the node s node editor double click that interface s Phy or Wphy module and then enable its Link Failure option to set the down times for that particular interface Module Edil m Paraneters Sating File H me esti phy hd _PZ linETai the Phy module in the node editor Note that a user can also set the down time periods of a link By double clicking a link a link attribute dialog will show up In the dialog a user can set the l
74. ulation These job control commands are Pause Continue Stop Abort Menu gt Simulation gt Reconnect Disconnect A user can disconnect the GUI from a currently running simulation job Doing this allows him her to quit the GUI program to do other things He she can come back later restart the GUI program and then reconnect to the disconnected simulation job Menu gt Simulation gt Submit 35 A user can directly submit a simulation job to the dispatcher for execution Its effect is the same as first running up the simulation and then immedi ately disconnecting the GUI from the just launched simulation job Playing back the Packet Animation Handle animation by Tool Bar at the bottom QA Im pir a When a simulation is completed the GUI system automatically enters mode 4 In this mode the toolbar at the bottom can control the progress of the play of a packet animation trace The 20fps frames per sec selection box can control the displayed animation quality The 100 selection box can control the display speed of the animation To speed up the animation a user can set it to 1000 or a larger value The knot of the time bar can be dragged to any location to jump directly to a desired time When the time bar is moving all the control buttons have their own functions 36 Doss Eee Soe ere Gee Eee co eee MLS oS af 393 000 000 000 The packet animation player
75. xisting modules with his or her own ones For example in the PSBM packet scheduling and buffer management module group three modules FIFO Random Early Detection Deficit Round Robin are currently supported A user may add one new PSBM module such as the RIO module to it Detailed information on how to add a new protocol module to both the simulation engine and the node editor is documented in the NCTUns 1 0 Moduel Writer Manual Screen Layout Explanation The following will briefly explain the screen layout of the node editor To see the node editor in the topology editor a user first switches the mode to the Edit Property mode by checking the File gt Operation Mode gt Edit Property command Then he she can double click a node that he she wants to edit After the node s dialog box shows up the user can then press the Node editor button to invoke the node editor to edit that node s protocol modules The node editor screen shot 38 At the top of the node editor are various module groups The protocol modules that share the same role in a protocol stack are grouped together under the same group name In the middle working area the protocol modules used by this node will be shown Here a chain of protocol modules represent the protocol stack used by a port interface The user can use the mouse to easily add delete or replace protocol modules in the working area At the bottom are seve

The NCTUns 1.0 Network Simulator GUI User Manual

Contents

Download Pdf Manuals

Related Search

Related Contents