lbi-38961a - edacs data gateway - The Repeater Builder`s Technical
Contents
1. The fan tray has five air movers that provide an air flow of 250 CFM and use ball bearings for high reliability A front access filter can be removed and replaced without removing the fan tray from the rack BACKPLANE The processing cards communicate over an industry standard VMEbus backplane The backplane has slots for ten circuit boards The first and last slot are terminated on the rear of the backplane as per the VMEbus specification 25 Ericsson Inc Private Radio Systems Mountain View Road Lynchburg Virginia 24502 1 800 528 7711 Outside USA 804 528 7711 Printed in U S A2. another radio or a group of radios An RDT can access the full range of IP Addressable hosts Acknowledgments and Error Reporting At the data link layer END uses positive acknowledgment The RDT receives a positive or negative acknowledgment from the RDI when it receives the data transfer request when the RDI receives the data and when the EDG receives the data There is no positive or negative acknowledge back to the RDT after the data leaves the EDG END returns the status back up to the IP product At the network layer the IP product may receive an ICMP message as a negative acknowledgment If an error occurs it may be logged at the host other components in the Ethernet Network the EDG the radio the RDI or another EDACS component depending on the error 17 RDTs with a Null Network Layer This configuration is useful in situations similar to those where a customer supplied network layer on the RDT would be useful In both situations IP host computers are used but END is not used The primary difference is that radio to radio messages messages larger than 512 bytes and multiple transport layer protocols are not needed Since the mobile applications developer is not using the network layer functionality the layer can be omitted The main difference between this configuration and RDTs without a network layer is that this is an unbalanced configuration The hosts use a network layer but the RDTs do not Protoco
3. 38961 RADIO DESTINED MESSAGE The following provides a simplified call flow for an RDI Host to radio message transfer Steps 2 and 9 do not apply to IP Host Computers and radio to radio messages 1 The host sends a message to the EDG 2 The EDG sends an acknowledgment to the host after the entire message is received forwards the burst to the radio as it receives it After the radio receives the entire burst it sends an ACK Map back to the EDG via the site informing it of the packets that the radio correctly received If necessary the EDG sends another burst containing packets the radio did not correctly receive and packets the EDG has not previously sent This sequence continues until the radio receives the entire message or until the EDG exhausts its retries 3 The EDG sends a call request to the IMC via a DIM 8 The radio sends the message to the RDI If the link message is large enough the radio sends the initial part of the message to the RDI while the radio is still 4 The IMC sends the call request to the site where the receiving the message from the EDG radio is located 9 If requested the EDG returns the acknowledgment to 5 The site tells the radio to go to a working channel to the host indicating whether the message was receive the message successfully transferred to the radio 6 The site returns the channel assignment to the IMC 10 The RDI acknowledges to the radio it has successfully The IMC connects
4. Over Current Protection Line Regulation Load Regulation Ripple Dynamic Response Filtering Status Indicators LBI 38961 SPECIFICATIONS Up to 8 control lines operating at either 19 200 or 9600 bps Up to 32 data lines minus the RDI Host Interface connections operating at 9600 bps EDACS Proprietary EDACS Network Layer selectable on a per unit and group basis Up to 16 RS 232 data lines operating at 9600 bps using DB25 connectors RDI Protocol versions 1 8a 1 91 and 1 92 None DB15 AUI Ethernet Connector Ethernet II aka IEEE 802 3 DIX Internet Protocol IP Version 4 RS 232 serial interface supporting VT100 type terminals or remote access via Telnet Centronics parallel printer interface 245 Mbyte fixed disk drive with SCSI interface 1 44 Mbyte 3 5 removable diskette drive with SCSI interface MS DOS format diskettes supported Conforms to FCC 20780 Part 15 Subpart J A and EN 55022 Class B Conforms to EN 60950 UL 1459 and CSA 225 110 VAC 10 60 Hz 220 VAC 10 50 Hz single phase 12 volts DC at 10 amps each 5 volts DC at 100 amps For all three channels 120 to 130 of nominal output on all channels On all channels 0 2 of rated output 0 8 of rated output 1 peak to peak at 50 MHz 3 max deviation to 25 75 step change Power line filter and internal filter for conducted emissions AC POWER ON indicator LBI 38961 Average Power Consumption EDG with no ports Each
5. on the type of the error Queuing and Flow Control Each HDI board has approximately 300K bytes of buffer space for queuing messages to the host computer The HDI usesthis queue when all of the ports to the host are busy Conversely the TSIs queue messages to radios if necessary If an RDI Host Computer and the EDG try to initiate a data transfer over the same port at the same time the EDG queues its message and services the host s transfer first When a port frees up the EDG sends out the message that was preempted before sending out any other queued messages IP HOST INTERFACE Protocol Layers The EDG physically connects to an Ethernet Network using a DB15 AUI Ethernet Connector This can be used with thick coax thin BNC coax or twisted pair 10BaseT using an IEEE 802 3 standard off the shelf transceiver The transceiver is purchased separately based on the network requirements The data link layer uses Ethernet II Protocol This is also known as IEEE 802 3 DIX Standard IEEE 802 3 Ethernet Protocol is not supported at this time The network layer uses Internet Protocol IP version 4 The Internet Activities Board defines the official standard for the InternetProtocol Internetworking with TCP IP Volume I by Douglas E Comer is an excellent but unofficial source of information about IP Except for the following the EDG fully supports the major features of the Internet Protocol 1 Subnetting is not supported at
6. that can be used when passing data The EDG connects to host computers using Internet Protocol IP over Ethernet and or Radio Data Interface RDI protocol over RS 232 serial links The EDG connects to the rest of the EDACS System through either an Integrated Multi site LBI 38961 Coordinator IMC for multi site systems or a Console Electronics Control CEC for single site systems not shown RDTs use the 9600 bps serial interface of the RDIs to connect to radios Depending on the radio it can contain an internal RDI or use an external RDI The EDG provides the ability to send data across multiple RF sites The EDG manages speed addressing and protocol differences so IP Host Computers on a Local Area Network LAN can communicate with radios on an EDACS Wide Area Network WAN In addition the EDG can be configured to minimize or eliminate custom communications software Ethemet Network RDI Host Computers Single Node EDACS Network Figure Equipment Overview LBI 38961 FEATURE LIST The Ericsson EDACS Data Gateway supports the following features e Call Types Individual Data Call Host Originated Group Data Call Multi site or Single site Radio to Radio Data Calls via the EDG e Non Proprietary Host Computer Interface 64K bytes per message Ethernet physical connection and Data Link Layer Standard IP Network Layer supporting class A B or C IP addresses Simultane
7. this time 2 A Host ID of all ones does NOT refer to all radios on an EDACS network The protocols that are used above the network layer are end to end conversations between the host and RDT Any headers they use are simply passed as data through the network to the RDT Except for the Transport Layer 13 LBI 38961 Protocol when the RDT is using a Null Network Layer the upper protocols are of no concern to the EDACS System The RDT Interface section explains this more fully Addressing From the host s perspective the RDTs are peer devices on another network In a simple configuration the EDG is the next gateway to use to send data to the RDTs In a more complex configuration there could be multiple gateways between the EDG and the host In either case the host is only concerned with the next gateway to use not the full topology of the internet The EDG Installation and Maintenance Manual contains information on the format of IP Addresses and assigning them EDACS RF Network Host Network Figure 8 Simple Configuration As Seen By the Host At the data link layer the EDG and host computers communicate using Ethernet Addresses The host computers and th DG_ useAddress Resolution Protocol ARP to learn each others Ethernet Addresses based on their IP Addresses The network layer uses the IP Address to decide where to route the message next For host originated messages the host addresses a
8. 15 Anti Biasin e e EE 15 RD Ts without a Network Layer cisrenan AEE ANE E e EERTE EE ETE AE 15 Protocol EE 15 E E 16 Acknowledgments and Error Reporting pt 16 RDTs with a Standard Network Layer Nt 16 Protocol ayers ws EES EES 16 E EE 17 Acknowledgments and Error Reporting Ne 17 RDIS with a Null Network Layer rii penini aia E R E A T A O 17 erte RTE 17 Addressin 352 55 0s Sekt kee E 18 Acknowledgments and Error Reporting pt 18 ADDRESS CONVERSIONS AND MESSAGE ROUTING A 19 RDI HOST COMPUTERS AND NON NETWORK LAYER RDTS ppp 19 IP HOST COMPUTERS AND NETWORK LAYER RDTS pp 19 Message from Host toRDT iis ni See ee Eer EE E 19 Message from RDT to HOSt succsitvtarentiecinn reindeer al ere 19 Copyright June 1995 Ericsson Inc 2 LBI 38961 TABLE OF CONTENTS CON T Page IP HOST COMPUTERS AND NON NETWORK LAYER RDTS ppp 20 Message from Host to RDT urinii ee ses een cat oan ee eit conta Miocene ceiver geed 20 Messages from RDT to Hostessen ae shack esceustbenecte ESA SESE EE eEE euas a eSEE 20 MESSAGE FLOW WITHIN THE EDACS SYSTEME cc eeeecccceeeseneeeceeseeeeeeceeenaeeeeeesnaeeeeeeees 21 RADIO ORIGINATED MESS AO 21 RADIO DESTINED MESSAGE Ne 22 OPTIMIZATIONS TTT 23 MAXIMIZING RF EFFI CIENO Y eeror poorest per sca Ser eet ee ee Eeer 23 LOAD DISTRIBUTION FOR RADIO ORIGINATED MESSAGES RN 23 RDTs Without a Network Layer 23 RDTs Watha Network Layers e
9. 32 modules see below The board attaches directly to the rear of the backplane and has four mass termination connectors Four ribbon cables distribute the serial interface signals RxD RxC TxD TxC and modem control signals DCD DTR RTS RI CTS from these connectors to the four SCI 232 modules SCL232 An SCI 232 converts serial I O signals from TTL to RS 232 voltage levels and routes them to a DB 25 connector One VCOM24 needs four SCI 232 modules to support all four ports The SCI 232 module includes jumpers to configure the port as DCE or DTE FIXED DISK DRIVE The fixed disk drive has a formatted capacity of 245 megabytes It is used for EDG software configuration files and activity logs The drive has a 3 5 form factor and has an internal SCSI bus controller The hard disk formatting is proprietary and is not compatible with MS DOS FLOPPY DRIVE The floppy disk drive has a 3 5 form factor and supports floppy disks with an MS DOS compatible formatted capacity of 1 44 megabytes The floppy disk drive is provided for transferring files to and from the hard disk DIAGNOSTIC TERMINAL The EDG includes a VT100 compatible terminal that connects to a serial port on the CAP board Using this terminal the system operator can view or print the EDG configuration and errorlog shutdown and restart the EDG or set the system time See the EDG User s Reference Manual for information on the commands available from the Diag
10. IONS AND MESSAGE ROUTING Installations may contain additional equipment between the host computers and the EDG Possible address conversions and message routing performed by additional equipment is not documented in this manual RDI HOST COMPUTERS AND NON NETWORK LAYER RDTS RDI Hosts and radios communicate using only EDACS Addresses The EDG is a transparent bridge between them and does not conversions IP HOST COMPUTERS AND NETWORK LAYER RDTS Message from Host to RDT 1 The host looks up the RDT s IP Address in its routing table and finds the IP Address of the EDG s CAP Board listed as the next gateway for the EDACS Network The host then forwards the message to the CAP Board using its Ethernet Address If the host does not know the CAP Board s perform any address LBI 38961 Ethernet Address it uses Address Resolution Protocol ARP to ask the CAP Board The CAP Board forwards the message to a TSI Board The TSI Board converts the destination IP Address to either an EDACS Logical ID LID or Group ID GID The TSI Board then sends the message to a radio or group of radios The radio RDI sends the message to the RDT using an XFERB command The EDACS Network Layer Header contains the IP Address of the host The TSI Board uses one of the LIDs assigned to it as the source EDACS Address in the XFERB Message from RDT to Host 1 The RDT sends the message to the radio RDI using an XFERB command T
11. LBI 38961A Technical Description EDACS Data Gateway ERICSSON 2 LBI 38961 TABLE OF CONTENTS Page PREBA EE 4 SPECIFICATIONS EE 5 OVERVIEW ET 7 FEATURE LIST een eaae coe aces ooh crate taeda cuccasPesaseon ceca cue tee thes ces esussahensb dpoetrowe reaped asec S Eata Toot 8 SYSTEM ARCHITECTURE eege ANE EE gen 8 TRUNKED SYSTEM INTERFACE OS 9 CENTRAL ACTIVITY PROCESSOR CAP 9 HOST DATATNIERRACROHDIL NEEN gedd eer dee 9 EDG SIZING rria eegene eseu sion wane cach eet Ee Eeer 10 NETWORKING CONCEPTS o earn reae eE TN NENNEN 10 SINGEE NEFWORKS n cerieirar ee e EEEO EEE ADOR E E T EE a 10 BRIDGING HOSTS AND EDACS NETWORKS 2 00 0 ceeeececcccccccceeeeeeseeeeeeeeeeeennaeeeeeeeeeeeeeaaaes 11 CONNECTING MULTIPLE NETWOR SN 12 INTERFACE SPECIFICATION T tataa N E TSSEA TEE 13 RDI HOST DATA INTERFACE AA 13 Protocol EE 13 Elte EE E 13 Acknowledgments and Error Reporting 3 13 Queuitig and Flow Controli geesde gees esha SE Pa ee ST eens a eg een ete ta 13 IR HESE INTERFACE EE ee REENEN 13 Protocol EE 13 E EE 14 Acknowledgments and Error Reporting 14 Que uins lt and Flow Control satiare at hee ee eee sete ese deed get 14 RADIO DATA TERMINAL ORDTINTERPRACR cc cecccccccceeeessteceeeeeeeeenaaeeeeeeeeeseeenaaees 15 Messaging Between the EDG and Radio eee eeeesesecesseeeseessseecscecseeceseeeesaeecsaeessaeesseesesaeeesaes 15 Queuing and Flow Controls nir ned ER lana da hipieii dete bates ia ehindaaniscadae de
12. The TSIs and sites send data via the Rockwell Modems at 9600 bps Each TSI can provide up to four communication ports with each communication port handling one data call at a time TSIs can be used in pairs with one designated as the Master and providing the control link to the IMC or CEC This allows two TSIs to share a single DIM Controller reducing the IMC hardware required without reducing throughput The EDG and EDACS Sites send data calls over audio lines using Rockwell Modems CENTRAL ACTIVITY PROCESSOR CAP The CAP Board supports the disk drives Diagnostic Terminal and optional printer It processes the configuration file and passes configuration information to the other boards It also provides an optional interface to host computers using Internet Protocol IP over Ethernet HOST DATA INTERFACE HDI Each HDI Board can support up to four ports The ports are individually assigned to hosts allowing a single HDI to support multiple hosts multiple HDIs to support a single host or multiple HDIs to support multiple hosts LBI 38961 EDG SIZING The number of TSI Boards should be selected based on the expected load This should include expected messaging between IP Host Computers and radios between RDI Host Computers and radios and between radios For most applications one TSI Board is needed for each HDI Board if any This is in addition to any TSI Boards needed to support the expected load from the other messa
13. This manual contains information for using the EDG command shell The command shell services the Diagnostic Terminal and Telnet logins EDG Configuration Reference Manual LBI 38964 This manual documents the commands used to configure the EDG Internetworking with TCP IP Volume I by Douglas E Comer This is an excellent but unofficial source of information about Internet Protocol EDACS Network Driver User s Manual LBI 39161 This manual documents how to install and use the EDACS Network Driver END This product provides a Medium Access Control MAC sublayer driver for use with off the shelf IP protocol stack products The END product is for use with MS DOS EDACS CommServ Programmers Guide LBI 38835 This manual documents the CommServ product CommServ provides an application program interface that simplifies RDT programming by providing an RDI Data Link Layer It is for use with MS DOS and PC DOS Radio Data Interface Protocol Specification Version 1 92 ECX 922 This manual documents the RDI Interface EDACS Interface Physical Layer Data Link Layer Network Layer RDI Protocol Host Interface Physical Layer Data Link Layer Network Layer Internet Protocol Host Interface Physical Layer Data Link Layer Network Layer General Specifications Diagnostic Terminal Printer Drives EMI Regulations Safety Power Supply Input Voltage Autosensing Output Voltage Remote Sense Over Voltage Protection
14. a DB 15 connector for Ethernet and a Centronics compatible printer connector Jumpers on the I O Transition Module allow the serial ports to be configured as DTE or DCE Like the P2 Adapter Assembly the I O Transition Module has sockets for SCSI terminating resistors VCOM24 SERIAL COMMUNICATIONS CONTROLLER The VCOM 4 is a high speed serial communications controller that supports the EDG s serial interfaces The VCOM24 can be configured as a TSI Master TSI Slave or HDI Powered by a 68020 microprocessor and two serial communications controllers the VCOM24 offers four full duplex serial ports that support asynchronous or byte synchronous protocols The VCOM24 alsohas a single full duplex asynchronous serial port that is used for the 24 DIM control data link when the VCOM724 is configured as a TSI Master The Reset button resets the EDG The Abort button is disabled During normal operation the VCOM24 Status indicators display the following INDICATOR Mode INDICATES RUN Flickers Local bus activity HALT OFF__ Boardisnothalted SYSFAIL OFF No board failure The Boot Sequence section of the EDG Installation and Maintenance Manual explains the meanings of the eight small LEDs The eight dip switches are not used and can be set to any combination VMEADAPT Module The VMEADAPT Module is a small circuit board that connects the I O signals from the VCOM24 s P2 connector to the SCI 2
15. a data path between the EDG and received the message the working channel and notifies the EDG 11 The RDI forwards the message to the RDT 7 The EDG breaks the message down into packets and sends the first burst of packets to the site The site RDT RDI Radio Site IMC EDG Host lt 1 2 gt lt 3 lt 4 lt en gt lt gt 7 lt 8 9 gt optional 10 gt lt 11 22 OPTIMIZATIONS MAXIMIZING RF EFFICIENCY In most configurations the wide area RF link has the lowest effective data transfer rate Normally it is also the most expensive area to add capacity Several methods can be used to maximize throughput 1 Minimize the amount of data being sent over the air Maintenance of forms and other static information at the RDT is one method of accomplishing this 2 Keep duplicate or unnecessary acknowledgments to a minimum 3 If possible send one 500 byte message instead of two 250 byte messages Unlike systems that use dedicated resources the EDG and radio must establish a link for each individual message 4 If messages are larger than 512 bytes split them on 511 byte boundaries if possible For example a 600 byte message would be split into a 511 byte message and an 89 byte message If the EDG receives a large message from an IP Host computer it will perform this optimization 5 Minimize collisions caused by trying to send and
16. addition to providing the Ethernet IP interface and servicing the EDG peripherals the CAP reads the configuration file and loads application software and 23 LBI 38961 configuration parameters onto other processor boards in the system Finally the CAP processes commands from the diagnostic terminal The Reset button resets the EDG The Abort button is disabled During normal operation the CAP indicators display the following INDICATOR Mode _ INDICATES FAIL OFF No board failure STATUS Flickers CPU activity RUN Flickers Local bus activity SCON ON Board is VMEbus Master Adapter Board The Adapter board is a small circuit board that routes the I O signals and grounds from its concentrated VMEbus backplane connector P2 to the Transition Module The board plugs directly onto the rear of the backplane and has two mass termination connectors Two ribbon cables carry the I O signals from these connectors to the transition module Also the Adapter Board has sockets for SCSI terminating resistors if the Adapter Board s SCSI interface is at the end of the SCSI bus Transition Module The Transition Module is a separate circuit board that receives the I O lines from the P2 Adapter Assembly ribbon cables and routes them to the appropriate industry standard connector on its panel The I O Transition Module has four DB 25 connectors for serial I O a 50 pin SCSI port connector
17. ecture of the EDACS Data Gateway its external interfaces to the rest of the EDACS System and the EDGs external interfaces to host computer equipment The EDG can be configured with either an IP Host Interface RDI Host Interfaces or both The TSI HDI and CAP boards communicate over the system bus One or more Trunked System Interface TSI Boards handle all communications to the rest of the EDACS trunked radio system The Central Activity Processor CAP provides the IP Ethernet Interface to host computers and system services such as disk I O printing and the local Diagnostic Terminal interface Optional Host Data Interface HDI Boards provide an interface to host computers using RDI Protocol LBI 38961 IMC CEC DATA INTERFACE MODULE TO HOSTCOMPUTERS CONTROL ROCKWELL UNK MODEMS ROCKWELL MODEMS TRUNKED SYSTEM INTERFACE MASTER TRUNKED SYSTEM INTERFACE SLAVE PORTS 1 4 PORTS5 8 Centronics Printer optional Diagnostic Terminal CENTRALACTIVITY PROCESSOR Ethernet ee HOSTDATA INTERFACE PORTS 1 4 FIXED DISK FLOPPY DISK SCSI BUS TO HOSTCOMPUTERS Figure 2 Internal EDG Architecture TRUNKED SYSTEM INTERFACE TSD TSIs connect to the rest of the EDACS System through one or more Data Interface Modules DIM in the IMC The TSIs and IMCs exchange control messages over the control link at 19 2k or 9 6k bps
18. ge paths listed previously While most configurations only require two or three TSI and HDI Boards an EDG can support up to eight TSI or HDI Boards For example if only IP Host Computers are used up to eight TSI Boards could be used If RDI Host Computers are used up to four TSI Boards and four HDI Boards could be used If both host interfaces are used a full EDG might consist of five TSI Boards and three HDI Boards NETWORKING CONCEPTS SINGLE NETWORKS For the purposes of this discussion a network is a physical media and protocol that allows multiple devices to communicate In the terms of the International Standards Organization s Open System Interconnection Reference Model OSI Model these are the Physical and Data Link Layers Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer Figure 3 OSI Model 10 Any device wishing to communicate with devices on a network must directly connect to the network using an interface that is compatible with the network A simple network could connect three host computers to each other using Ethernet Figure 4 Ethernet Network Each of the devices would physically connect to the Ethernet cable They would communicate with each other using Ethernet Addresses and Ethernet Protocol Unfortunately there is no single type of network that is best for all situations Ether
19. gram could be written to receive all ICMP messages filter those of interest and return them to the application program on request 3 Errors logged by other components in the host network 4 Errors logged by the EDG The severity of errors logged by the EDG is selectable See the log command in the EDG User s Reference Manual for more information 5 Errors logged by other EDACS components such as the IMC Site Controller or radio RDI It is also possible for a message to successfully reach the radio and the acknowledgment to fail to reach the EDG In this case the EDACS System treats the message as if it errored even though the radio RDI and RDT see it as a successful message The EDG will send an ICMP Message back to the host computer Queuing and Flow Control The EDG s IP Host Interface uses several queues to send and receive IP fragments Under normal conditions fragments spend very little time in these queues In extreme cases the IP Host Interface could receive messages at a faster rate than it can handle In this situation the interface accepts as many messages as it can and issues ICMP Source Quench messages for the rest RADIO DATA TERMINAL RDT INTERFACE RDTs can be configured in a variety of ways Normally the RDT configuration is chosen for close compatibility with the type of host interface Generally if the host has a network layer then the RDT should also have a network layer If the host does no
20. group of 4 TSI Ports Each group of 4 HDI Ports Fan Power requirements Air flow rate Filter Physical EGE Standard Cabinet Cabinet Colors Housing Trim Cabinet Dimensions Height Width Depth Material 16 gauge cold rolled steel Status Inputs and Outputs Board LEDs General Purpose CPU Intelligent Serial I O Controller Drive LEDs Fan LED Remote Reset Input Connector Environmental Temperature Operating Non Operating Humidity Diagnostics Error Detection System Configuration Controlled Shutdown 280W 70W 40W 12 VDC from power supply 250 CFM Removable aluminum filter Light Gray Black 69 1 6 175 5 cm 24 61 cm 24 61 cm FAIL STATUS RUN and SCON RUN HALT and SYSFAIL Disk activity lamps on both drives 12 VDC power indicator lamp Shorting the Remote Reset pins on front panel of CAP Board forces a system RESET 0 to 40 C 20 to 85 C to 95 noncondensating except for removable diskette drive Run time errors logged in a file for viewing or printing Configuration file can be viewed from the Diagnostic Terminal System operator can cause a graceful system shutdown so calls in progress are completed OVERVIEW The Ericsson Inc EDACS Data Gateway EDG allows Radio Data Terminals RDT to communicate with stationary host computer equipment and other RDTs through the EDACS trunked two way radio system The block diagram below gives an overview of the equipment
21. he EDACS Network Layer Header contains the IP Address of the host The destination EDACS Address in the XFERB is one of the IDs in the block assigned to the EDG One of the TSI boards receives the message from the radio The TSI routes the message on to the CAP or out to another radio based on the IP Address in the Network Layer Header If the message is to a host the CAP Board forwards it using its Ethernet Address If the CAP does not know the host s Ethernet Address it uses ARP to ask the host Ethemet Network Intemal EDG Network EDACS Network Figure 14 IP Host Computers And Network Layer RDTS 19 LBI 38961 IP HOST COMPUTERS AND NON NETWORK LAYER RDTS Message from Host to RDT 1 The host looks up the RDT s IP Address in its routing table and finds the IP Address of the EDGS CAP Board listed as the next gateway for the EDACS Network The host then forwards the message to the CAP Board using its Ethernet Address If the host does not know the CAP Board s Ethernet Address it uses ARP to ask the CAP Board The CAP Board forwards the message to a TSI Board The TSI Board converts the host s IP Address to an EDACS Logical ID LID The TSI Board converts the destination IP Address to either an EDACS Logical ID or Group ID GID The TSI Board then sends the message to a radio or group of radios 4 The radio RDI sends the message to the RDT using an XFERB command It contains
22. ia the IMC The bottom LED indicates modem data from EDG During a successful Individual Data Call all of the LEDs are lit regardless of the direction of the data being transferred During a successful Group Data Call all of the LEDs but LBI 38961 the fourth LED are lit This is because radios do not acknowledge receipt of data during a Group Data Call Rockwell Modem The Rockwell Modem is designed for multipoint and networking applications It allows full duplex operation over 4 wire dedicated unconditioned telephone lines or half duplex operation over the general switched telephone network at 9600 baud CROSS CONNECT PANEL The Cross Connect Panel is a printed circuit board that allows cables from the VCOM24 boards with DB 25 connectors to plug into the Modem Unit Shelf backplane jacks One side of the Cross Connect Panel has connectors that mate with the Modem Unit Shelf backplane jacks The panel routes signals off those connectors to DB 25 connectors mounted on the opposite side of the panel POWER SUPPLY The EDG uses a triple rail supply offering 5 12 and 12 VDC in a single nineteen inch rack mounted chassis The AC input circuitry is autoranging capable of using 110 VAC at 60 Hz or 240 VAC at 50 Hz The power supply has remote sense lines for all three voltage rails and includes an AC POWER solid state LED indicator FAN A removable fan tray positioned directly under the card cage cools the EDG circuit boards
23. ing The addressing in this situation is a hybrid of the network layer and non network layer methods From the host s perspective the RDTs are peer devices on another network just as in any network layer configuration However from the RDTs perspective the host is on the EDACS Network An RDT can access a maximum of sixty three different hosts EDACS RF Network Host Network Figure 12 Configuration As Seen By the Hosts 18 VM Radio RDT amp RDI Radio RDT amp RDI Radio amp RDI Radio amp RDI Figure 13 Configuration As Seen By the RDTs The host computers send and receive messages using IP Addresses The RDTs send and receive messages using EDACS Addresses The EDG converts between them using a configuration table Acknowledgments and Error Reporting At the data link layer the RDT receives a positive or negative acknowledgment from the RDI when it receives the data transfer request and when the RDI receives the data The data link layer can ask for a positive acknowledgment when the EDG receives the data The EDG filters outs network layer error messages to RDTs without a network layer The EDG drops all ICMP messages except Echo Requests and Echo Replies components in the Ethernet Network the radio the RDI or If an error occurs it may be logged at the host other EDG the component another EDACS depending on the error ADDRESS CONVERS
24. ing MS DOS It complies with the Network Driver Interface Specification NDIS and advertises itself to off the shelf IP products as an Ethernet Driver An off the shelf IP product provides an IP Network Layer END converts between IP headers and EDACS Network Layer Headers END also handles ARP and RARP requests locally The protocols used above the network layer are of no interest to the EDACS System Any headers used by these protocols look like part of the data message to the EDACS System LBI 38961 Applications TCP UDP EDACSNL Ethemet themet IP Ethemet Host EDAC S System Applications TCP UDP Transport Layer Network Layer Data Link Layer Physical Layer RDT Figure 10 Typical Protocol Stack With a Standard Network Layer Addressing The various layers in the protocol stack use several different types of addresses to perform different functions At the data link layer the EDG and radios communicate using EDACS Addresses For a message to a radio or group the EDG uses a configuration table to convert the IP Address to the EDACS Address For messages from radios the EDG reserves the EDACS Addresses one through fifteen END sequences through these addresses to distribute the load in case the EDG is configured with multiple TSI Masters All radio originated messages are sent to the EDG even messages to another radio The network layer uses the IP Address to route the message to a host
25. it receives it After the EDG receives the entire burst it sends an Ack Map back to the radio informing it of the packets the EDG correctly received If necessary the radio sends another burst containing packets the EDG did not correctly receive and packets that the radio has not previously sent This sequence continues until the EDG receives the entire message or until the radio exhausts its retries The radio tells the RDI the status of the message transmission to the EDG lt 12 optional 4 The radio informs the site that it has a message 11 If the EDG successfully received the message the EDG sends the message to the destination The message 5 The site assigns a working channel and informs the transfer from the EDG to the destination proceeds radio independently of any other signaling from the RDT 6 The site sends the call assignment to the IMC The 12 If requested the RDI tells the RDT whether the EDG IMC sends it on to the EDG successfully received message or not Note that the RDT does not receive any direct confirmation the host 7 The EDG selects a TSI Port and informs the IMC The successfully received the message IMC sets up a data path between the EDG and the working channel RDT RDI Radio Site IMC EDG Host 1 gt 2 gt lt 3 4 gt lt 5 6 gt lt 7 lt 8 Q lt gt lt 10 11 gt 21 LBI
26. l Layers RDTs physically connect to radio RDIs via a 9600 bps asynchronous serial link The data link layer uses RDI Protocol If the RDT is using MS DOS the CommServ product can be used to reduce the coding effort The EDACS CommServ Programmers Guide lists the minimum requirements for using CommServ There is no network layer on the RDTs For radio originated messages the EDG adds a network layer For messages to the radios the EDG strips the network layer It is expected that a relatively simple transport layer protocol such as UDP would be used above the network layer and the application would provide some transport layer services such as performing retries Normally the transport layer protocol is of no concern to the EDACS System and there are no restrictions placed on it However in this configuration only one transport layer protocol can be used at a time The IP Network Layer Header contains a LBI 38961 Applications and some Transport IP Ethemet Host EDACS System Applications and some Minimal Transport Layer Network Layer Data Link Layer Physic al Layer RDT Figure 11 Typical Protocol Stack with a Null Network Layer Protocol field which is used by the network layer on the host computer to determine which transport layer protocol to pass the data up to Because the IP Network Layer Header is built by the EDG it must be configured with the protocol the customer wishes to use Address
27. net networks perform well when used to connect devices at the same location However Radio Data Terminals RDTs could not be used in mobile applications if they were connected to an Ethernet cable running through a building This leads to multiple network types to solve different networking needs The devices on the Ethernet Network use Ethernet cable as their physical media and use Ethernet Addresses and protocol to communicate The devices on the EDACS RF Data Network use radio frequencies as their physical media and use EDACS Addressesand protocol to communicate This configuration works well until an RDT on the EDACS Network needs to communicate with a host on a different site or on the Ethernet Network The EDG provides two solutions to this problem that can be used individually or together LBI 38961 Ethemet Network EDACS RE Data Network Figure 5 Two Unconnected Networks Host Computers EDACS Network Figure 6 Host Computers Bridged To an EDACS Network BRIDGING HOSTS AND EDACS NETWORKS The EDG can be used as a bridge between RDTs on an EDACS Network and host computers using the RDI Host Data Interface Connecting host computers and RDTs by bridging has the following advantages 1 Host computers and RDTs can communicate regardless of the RF site the radio is logged into A single host computer can communicate with multiple radios simultaneously Host comp
28. nicate regardless of the RF site the radio is logged into 2 A single host computer can communicate with multiple radios simultaneously 3 The EDG connects to the host computer using non proprietary protocols This reduces the amount of custom software required 4 The EDG is compatible with the EDACS Network Driver END software for the RDT This allows the use of off the shelf IP protocol stack products In this configuration applications written for TCP and UDP can be used or developed Ethemet Network EDACS Network Figure 7 Internetworking Using an EDACS Data Gateway EDG 12 INTERFACE SPECIFICATION RDI HOST DATA INTERFACE Protocol Layers RDI Hosts physically connect to EDG Host Data Interface HDI ports via one or more 9600 bps asynchronous serial links The data link layer supports RDI Protocol Version 1 92 is recommended for new applications Versions 1 91 and 1 8a are supported for existing applications In addition to the standard RDI Protocol features the minimum time before retrying a message is not a fixed 45 seconds The EDG can be configured to raise or lower this time For more information see the MSG_TIMEOUT command in the EDG Configuration Reference Manual LBI 38964 If the RDI Host is using MS DOS the CommServ product can be used to reduce the coding effort The EDACS CommServ Programmers Guide lists the minimum requirements for using CommServ There is no netwo
29. nostic Terminal One Diagnostic Terminal is directly connected to the EDG The EDG can be configured to allow zero to four terminals to remotely log in at the same time using Telnet Access to the Diagnostic Terminal is restricted by user id and password User ids can be added and removed by the customer Passwords can be changed by the customer Some Diagnostic Terminals do not save their tab settings between power cycles The tab settings should be restored to the default tab every 8 columns after each power cycle Some of the Diagnostic Terminals have a Block Mode key near the enter key Pressing this key disables the terminal until it is pressed again MODEM UNIT SHELF The Modem Unit Shelf is a rack that holds the Modem Interface Modules Rockwell Modem Modules and Cross Connect Panel These modems provide the audio data path between the EDG and an EDACS System The EDG uses one Modem Interface module and one Rockwell Modem card per TSI port While the shelf can hold up to ten Modem Interface Modules and Modems normally a maximum of eight per shelf is used to simplify the wiring Modem Interface Module A Modem Interface Module is used with each modem to convert the TTL modem input and output signal levels to RS232 signal input and output levels see LBI 38564 for more information Each Modem Interface Module contains 5 Status LED s The top three are normally on The fourth Status LED indicates modem data from the site v
30. ost If an error occurs it may be logged atthe EDG another EDACS component the radio or at the RDI depending on the error ICMP messages from IP Hosts are not used to return error codes to RDTs in this configuration The EDG filters out all ICMP messages to RDTs except Echo Requests and Replies 16 negative RDTs with a Standard Network Layer This configuration eliminates the need for custom communications software when used with an IP Host computer Applications can be written using standard TCP or UDP transport layers This configuration also supports radio to radio messages and messages larger than 512 bytes The use of Telnet terminal emulation and FTP file transfer is not recommended at this time To achieve maximum performance it is important to keep collisions to a minimum This is true for any transport layer However with TCP s sliding window protocol it is especially important that protocol stacks in the RDTs and Hosts are configured correctly The EDACS Network Driver User s Manual contains the correct settings for the RDT In some situations the TCP software in the Host cannot be configured to reduce collisions to an acceptable level Using UDP may be a better solution in these situations Protocol Layers RDTs physically connect to radio RDIs via a 9600 bps asynchronous serial link The data link layer uses the EDACS Network Driver END END is a Medium Access Control MAC sublayer driver for PCs runn
31. ous use of multiple Transport Layer Protocols TCP UDP or customer defined Proprietary Host Computer Interface 512 bytes per message RS 232 Physical connection RDI Data Link Layer with positive acknowledgment Protocol Conversion The EDG converts data messages addresses and error messages between the various interface types e Flow Control and Queuing The EDG manages the speed differential between the various interface types Configurable queues and message timers are available for messages destined for radios and RDI Hosts Queuing is not needed for IP Hosts due to the 10 MHz speed of the interface e Robust Operation The EDG continues call processing when an EDACS System is in Failsoft The EDG helps prevent data corruption due to radio biasing e Flexible Configuration The EDG is configured through an ASCII text file The configuration can be verified on an MS DOS PC e Error Logging The EDG can log detected errors to a disk file the Diagnostic Terminal a remote terminal and or to a printer as desired Three levels of reporting can be selected Remote Login and File Transfer The EDG can be accessed using Telnet to login or FTP for file transfer Remote Software Upgrades are supported e Statistics Gathering and Display The EDG maintains loading statistics that can be displayed and cleared as desired SYSTEM ARCHITECTURE The block diagram below shows the system archit
32. radio or group of radios using the unique IP Address assigned to each radio and group Normally the host has a single entry added to its routing table instructing it to use the EDG s CAP Board as the next gateway for messages being sent to any destination on the EDACS Network For messages from a radio to a host the EDG receives the message examines the IP Address and forwards the message on to the host computer Acknowledgments and Error Reporting The IP Network Layer is a best effort delivery system Successful messages are not acknowledged Typically a positive acknowledgment is built into one of the higher 14 protocol layers The EDACS System generates an error indication if an error occurs after the EDGreceives a message and before the radioacknowledges the receipt of the message Unsuccessful messages may generate one of the following error indications 1 Error return codes from system calls on the host computer These error codes and their meanings vary depending on the host type 2 Internet Control Message Protocol ICMP messages The EDG or another component in the host network may return ICMP messages If an error occurs sending an ICMP message back to the host the ICMP message is dropped The EDG Installation and Maintenance Manual contains a list of the ICMP Messages the EDG returns On most host computers ICMP messages are not returned to the application program that sent the original message If desired a pro
33. ransport RDI Host EDACS System Application and Transport Data Link Layer Physic al Layer Figure 9 Typical Protocol Stack With No Network Layer The protocols that are used above the network layer are of no interest to the EDACS System Any headers used by these protocols look like part of the data message to the EDACS System Addressing RDI Hosts and radios communicate using EDACS Addresses at the data link layer An RDT can access a maximum of sixty three different hosts The EDG routes the messages to and from the host The EDG is transparent to both the host and the RDTs Since there is no network layer there is no network layer address In this configuration RDTs can only send individual messages to hosts RDTs cannot send group messages or individual messages to other RDTs If messaging between radios is desired the originating RDTs must send the message to an application on a host computer The host application would then send the message on to the desired radio s Acknowledgments and Error Reporting The RDT receives a positive or acknowledgment from the RDI when it receives a data transfer request XFERB and when the RDI receives the message If selected in the data transfer request the RDT also receives a positive or negative acknowledgment based on the reception of the message by the EDG There is no positive or negative acknowledge back to the RDT after the EDG begins sending the message to the h
34. receive data on a radio at the same time If a host computer is expecting to receive a reply to a message no other messages should be sent to the same radio while the host is waiting on the response If the RDTs are using END the EDACS Network Driver User s Manual lists the optimal configuration parameters for the recommended third party IP Products LOAD DISTRIBUTION FOR RADIO ORIGINATED MESSAGES If the EDG is configured with multiple TSI Boards throughput may be improved by rotoring radio originated calls between the available TSI Boards to distribute the load The EDG accepts radio originated messages from the IMC using two methods depending on whether the RDT is using a network layer RDTs Without a Network Layer RDTs that do not use a network layer send messages to the EDACS Address of the host Within the EDACS System the EDG acts as a proxy for the hosts so it can intercept and forward radio originated messages This LBI 38961 allows the EDG to be transparent to both the RDTs and the RDI Host Computers Rotoring can be accomplished by assigning multiple EDACS Addresses to the same RDI Host computer in the EDG The RDTs would then sequence through the host addresses on subsequent messages The host addresses would be spread across the TSI Masters distributing the load RDTs With a Network Layer RDTs that use a network layer send messages directly to one of the EDACS Address of the EDG The EDG uses the IP Addre
35. reduce its output rate If the EDG is saturated it sends the source of the message an ICMP control message asking it to reduce its output rate The EDG also deletes messages that have been queued for the specified time and limits the number of messages queued Anti Biasing Protection Large messages that contain a disproportional amount of either binary zeros or ones can bias a radio causing an increase in failed messages Some radios have a greater ability to resist biasing than others but most radios are susceptible The EDG can be configured to support Bias Reduction Encoding BREN Before sending a message to a radio the EDG encodes the message to balance the number of binary zeros and ones The receiving RDI decodes the message before forwarding it to the RDT For radio originated messages the EDG decodes messages encoded by the RDI This feature may increase or decrease the overall throughput depending on the reduction in retries verses the additional BREN overhead RDTs without a Network Layer This configuration is useful when communicating with an RDI Host Computer Protocol Layers RDTs physically connect to radio RDIs via a 9600 bps asynchronous serial link The data link layer uses RDI Protocol If the RDT is using MS DOS the CommServ product can be used to reduce the coding effort The EDACS CommServ Programmers Guide lists the minimum requirements for using CommServ 15 LBI 38961 Application and T
36. rk layer on RDI Hosts While it is doubtful that an RDI Host would be used to communicate with an RDT with a network layer there are no restrictions to prevent this In this case the EDG would add the network layer for messages to the RDT and strip the network layer for messages from the RDT The protocols used above the network layer are of no interest to the EDACS System Any headers used by these protocols look like part of the data message to the EDACS System Addressing RDI Hosts and radios communicate using EDACS Addresses EDACS Addresses can be assigned to hosts individual radios and to groups of radios Acknowledgments and Error Reporting The RDI Host receives a positive or negative acknowledgment from the HDI when it receives a data transfer request XFERB and again when the HDI receives the message Ifselected in the data transfer request the RDI Host also receives confirmation based on the reception of the message by the radio RDI There is no positive or negative acknowledge back to the RDI Host after the message leaves the radio If the RDI Host does not request confirmation the EDG frees the host port immediately after the data transfer LBI 38961 between the EDG and the host is complete If the RDI Host Computer does request confirmation the EDG frees the host port after returning the confirmation If an error occurs it may be logged atthe EDG another EDACS component the radio or at the RDI depending
37. ss in the EDACS Network Layer Header to forward the message to its destination This allows RDTs to use the full IP Address range If any RDTs are configured with a network layer the EDG automatically assigns EDACS Addresses one through fifteen to itself in addition to the addresses of the host computers it is acting as a proxy for If the EDACS Network Driver is being used it sequences through addresses one through fifteen automatically This distributes the load of radio originated calls across the available TSI Masters without requiring the RDT to have knowledge of the EDGs configuration Customers developing their own network layer may wish to do the same thing COMPONENT DESCRIPTION The EDACS Data Gateway is a multiprocessor system consisting of a general purpose microcomputer board and multiple microprocessor based intelligent serial communications controllers These microcomputer boards communicate over an industry standard VMEbus backplane The EDG also includes mass storage devices and data modems for transferring data to the EDACS System CENTRAL ACTIVITY PROCESSOR CAP Using the 68030 microprocessor the CAP Board is a general purpose computing board that provides typical computer peripheral interfaces for the EDG These include disk facilities through a Small Computer Systems Interface SCSD bus a Centronics parallel printer connection an Ethernet connection and four serial port interfaces for ASCII terminals In
38. t have a network layer then the RDT should not have a network layer However this is not required The EDG compensates if an unbalanced configuration is chosen The network layer software on the RDT can either be provided by Ericsson or be supplied by the customer The EDG s configuration tells it which RDTs radios use a network layer In addition to enabling or disabling the network layer for all radios the RDTs can be configured individually or in ranges Messaging Between the EDG and Radio The data link layer protocol used between the EDG and the radios is a hardened protocol designed specifically for the RF environment If necessary portions of the message may be repeatedly transmitted in order to complete the data call Once a call has been established working channel assigned the EDG and radio attempt to get the message through for up to seven seconds before giving up Queuing and Flow Control Each TSI Master has approximately 300K bytes of buffer space for queuing messages to radios Conversely the HDIs queue messages to RDI Host Computers if necessary If the EDG s first attempt to send a message to a radio fails because there are no working channels available or because the radio is in a voice call the EDG tries three additional times at 2 second intervals to get a channel before giving up on the call If all of the attempts fail the LBI 38961 EDG sends the source an ICMP Source Quench message asking it to
39. the EDACS LID of the host Messages from RDT to Host 1 The RDT sends a message tothe radio RDI It contains the EDACS LID of the host The radio sends the message to a TSI board on the EDG The TSI Board converts the radio and host LIDs to IP Addresses It then forwards the message to the CAP Board The CAP Board forwards the message to the host using its Ethernet Address If the CAP Board does not know the host s Ethernet Address it uses ARP to ask the host Ethemet Network Intemal EDG Network EDACS Network 20 Figure 15 IP Host Computers And Non Network Layer RDTS MESSAGE FLOW WITHIN THE 8 EDACS SYSTEM RADIO ORIGINATED MESSAGE 2 The following provides a simplified call flow for a radio to host data message transfer 1 The Radio Data Terminal RDT begins transferring a message to the Radio Data Interface RDI using RDI 1 92 protocol 2 The RDI begins pipelining the message to the radio using Mobile Signaling Protocol 3 The RDI acknowledges tothe RDT that it has successfully received the message This may occur earlier or later depending on the size of the message LBI 38961 The radio acknowledges to the RDI that it has successfully received the message This may occur earlier or later depending on the size of the message The radio breaks the message down into packets and sends the first burst of packets to the site The site forwards the burst to the EDG as
40. ut utiiserbtt a TE sande aizeskea sac E RE E TA 23 COMPONENT DESCRIPTION riren tvs EA AE E AU EA E OAE 23 CENTRAL ACTIVITY PROCESSOR CA 23 Adapter Board ainat rane e eege EE A E dE Ee E R 24 Transition Modules eserini Eeer E E E OTa aE AS geed 24 VCOM24 SERIAL COMMUNICATIONS CONTROLLER ee ecccccccceeeeeeeenneeeeeeeeennnaeeeeeees 24 KREE A UE 24 24 FLEXED BIEI L B iI AVA Bee E E 24 BRORBY DRIVE eeh 24 DIAGNOSTIC TERMINAL cccccccccccceeeeeesnnceeeeeeeeennaeeeeceeeeseeennaaeeceeeeeseeeeaaaeeeeeeeeeeeeeaaeeeeeees 25 MODEM UNIP SHEEP oe iii ieroci a o ter teretea cee tet R ATERRAR ACERRA RE 25 Modem Interface Modules ge eg eg ch 25 Rockwell Modems secs oe seet sees tes deisde e Z n seube e det Eed bens deet EENS de deg 25 CROSS CONNECT PANED sss dices a ANA ee RRR Ani 25 POWER SUPPE Ya OUEN E E A ITST T 25 EE 25 BACKPLANE ee eege 25 CREDITS EDACS is a registered trademark of Ericsson Inc EDG is a trademark of Ericsson Inc MS DOS is a trademark of Microsoft Corporation LBI 38961 PREFACE This is one of four manuals for the EDACS Data Gateway EDG It contains a detailed description of the EDG capabilities interfaces and hardware Other relevant documents are EDG Installation and Maintenance LBI 38962 This manual contains installation and troubleshooting information This manual also includes the boot sequence and network planning EDG User s Reference Manual LBI 38963
41. uters and their applications can easily be migrated from single site EDACS RF Data Networks to bridged networks 11 LBI 38961 4 Host computers can receive a positive acknowledgment that their message has been received by the radio 5 RDI Protocol can be implemented in RDTs with limited processing power 6 Several third party message switches converters exist based on this configuration protocol CONNECTING MULTIPLE NETWORKS The EDG can also be used as a gateway between EDACS Networks and host computers on an Ethernet Network Connecting multiple networks even if they are the same type is known as Internetworking The connected networks become a single internet Internetworking is accomplished by performing two actions First a gateway is connected to both networks The gateway has an interface to each network and is able to translate messages between them Next to simplify internetworking a network layer is used above the data link layers The network layer provides a consistent addressing method protocol and interface across the internet While the network layer address provides a consistent address across an internet it cannot be used to actually send data across a specific network The network layer address must be converted to a data link layer address specific to the network type Connecting host computers and RDTs by Inter networking has the following advantages 1 Host computers and RDTs can commu
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