Manuals / AT&T / Computer Equipment / Network Router

AT&T 7100 series, 7500 series, 2500 series, 7200 series Communication System Networking AN Overview

Models: 7400 series 2500 series 7200 series 7500 series 7300 series 7100 series

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2. COMMUNICATION SYSTEM NETWORKING — AN OVERVIEW

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A network is an interconnected group of communications systems that can exchange voice and data across the transmission media that connect them. Arranging communications systems into networks involves physically linking the systems (nodes) together with the appropriate hardware. In addition, it involves installing and administering the networking software.

Chapter 1 of this manual tells you about the hardware that you can use to physically link communications systems with each other. This chapter provides an overview of the software that you must activate and administer for network communication.

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AT&T 7100 series, 7500 series, 2500 series, 7200 series, 7400 series, 7300 series Communication System Networking AN Overview

Contents

Definity Communications System Page Contents Communication System Networking AN Overview Multiplexing Outside the SwitchTandem TIE Trunk Networks Data Connectivity AN Overview Distributed Communications System DCSData Communications Capabilities Special Data FeaturesRelated Documents Synchronization of Digital Facilities Data Communications ConfigurationsGlossary Trunking Terms and Capabilities Communications ProtocolsIndex List of Figures Mpdm DSUFigure B-1 Options for Synchronization Figure B-11 External and Internal Reference Levels BCC List of TablesEIA RS-232D V.28 LEADS/DEFINITIONS EIA RS-232C V.28 LEADS/DEFINITIONSEIA RS-449 V.24 LEADS/DEFINITIONS EIA RS-366 LEADS/DEFINITIONSXvi Contents Prerequisite Skills and Knowledge About this DocumentDocument Organization ∙ Glossary ∙ Index PartAT&T HOW to Make Comments about this DocumentXx about this Document Introduction to Connectivity 2INTRODUCTION to Connectivity Analog Transmission Transmission TypesDigital Transmission Analog-to-Digital Conversion Analog VS. Digital 6TRANSMISSION Types Transmission States Entering the SwitchVoice Transmission 8TRANSMISSION States Digital Switch ⎜ Module Exiting the SwitchCircuit Packs Protocol Layers Data Transmission12TRANSMISSION States Originating Switch Destination Layer 1 Protocols Protocols UsedProtocol States Layer 2 ProtocolsConnectivity Rules ⎜DMI Mode Code16TRANSMISSION States Types of Multiplexing Multiplexed CommunicationFrequency-Division Multiplexing Time-Division MultiplexingMultiplexing Over DS1 Facilities Statistical MultiplexingAlternating Mark Inversion Line CodingZero Code Suppression ZCS Line Coding B8ZS Line Coding Restricted ⎜ Unrestricted Signal Inversion⎜ DMI 7Data-Module Capabilities Part 2 Framing D4 FramingD4 Framing SignalingESF Framing Robbed-Bit Signaling ⎜ Channels 24th Channel ⎜ 24th Channel 24th-Channel SignalingESF ⎜ Frame No⎜ DMI-BOS Trunk Types/Destinations ⎜ Signaling Types⎜ Isdn PRI Multiplexing onto T1 Trunks Multiplexing Outside the SwitchCDM CEM Host Digital DMI PBX Getting the Signal Ready for the Central Ofﬁce Compressing the SignalAltering Channel Assignments on T1 Trunks Microwave System T1 Trunk Capacity Multiplexing with MicrowaveDR23N DR18M DR18W DR23W Demultiplexing10.Possible Multiplexed Connections Statistical Multiplexing Application TrunkingLocal Exchange Trunks Tie Trunks Auxiliary Trunks Special-Access TrunksMiscellaneous Trunks Release Link Trunks RLTsHost-Access Trunks Remote Access TrunksAdvanced Private Line Termination Aplt Trunks ConnectivitySystem 85/G2 Administration Administration OptionsSignaling Types Trunk Type Signaling ProtocolsComm Type System 75/G1 AdministrationGroup Type DS1 OptionsTrunk Tables Interface CircuitTrunking 44TRUNKING 11.Generic 1 and Generic 2 Digital Trunks Voice BCC 46TRUNKING Trunking 48TRUNKING Trunking 50TRUNKING Trunking 52TRUNKING Communication System Networking AN Overview Types of Networks Network Evolution PEC Software ⎜ Network Type S75/G1 S85/G2 PackageDCS Software CapabilitiesSystem 75 and Generic 1 UDP Package System 75 and Generic 1 PNA Package DIMENSION, System 85, and Generic 2 Multipremises PackageNetwork Call Processing Distributed Communications SystemUniform Numbering Internal Dial PlanRouting the Call DAC + EXT To ARS Auxiliary Call Information Selecting a Routing Pattern Automatic Alternate Routing∙ RNX Selecting a Trunk Group ∙ Where the trunk group appears in the list of preferences∙ The FRL of the call Modifying the DigitsAnalyzing the Dialed Number Automatic Route SelectionCommunication System Networking AN Overview To AAR Selecting the Routing Pattern Networking Feature Parameters Network AdministrationPrivate Network Trunks ⎜ Maap ⎜ Vmaap System Definity Feature PBX 20COMMUNICATION System Networking AN Overview Interactions with Other Networks Tandem TIE Trunk Networks2TANDEM TIE Trunk Networks Attendant Lines ⎜ Main Satellite ⎜ Trunks Main-Satellite Conﬁguration MS/T ConfigurationsMain-Tributary Conﬁguration MS/T Features Networking Package Multipremises with ETA Main Networking Package PNA, ETN Routing Outgoing Calls Routing Incoming CallsEngineering Considerations Other Routing CapabilitiesInteractions Page ETN Configurations ETN Trunks Page Access and Bypass Access Tie Trunks Off-Net Trunks FeaturesUniform Numbering Plan Attendant ETN Interactions with Other Networks Extension Number Portability Clusters Software-Deﬁned Network Call Routing SDN to ETN Call Routing ETN to SDN Release Link Trunk Networks CAS and ACD Automatic Call Distribution Centralized Attendant ServiceMain-Satellite/Tributary Networks Distributed Communications System ClustersDistributed Communications System DCS DCS Clusters Switch Node CapacityDCS Links Switch Physical Links ⎜Logical Channels/Link Signaling LinksSignaling Link Speed Signaling Link ProtocolTransmission Media Direct Link DCS Connections Linkage Design Distributed Communications System DCS Equipment Distance Limitation DCS Signaling Link ConnectionsMTDM/MPDM System 75 or Generic 1 G1 to System 75 or G1System 75/G1 Signaling Channel DCP System 85 or Generic 2 G2 to System 85 or G2 MtdmModem System 75 or Generic 1 G1 to System 85 or Generic 2 G2 RS232C to RS449 Conversion Dciu Transparent Features Dimension Signaling LinksTransparent Attendant Features Attendant Call Waiting⎜ ACA Attendant Control of Trunk Group AccessAlphanumeric Display Automatic Circuit AssuranceTrunk Group Busy/Warning Indicators Class-of-Service/Restriction DisplayBusy Veriﬁcation of Terminal Lines Calling Number DisplayAlerting-Distinctive Ringing Transparent Voice Terminal FeaturesAutomatic Callback on Busy or No Answer Call Forwarding Call Coverage ToneCall Waiting Leave Word Calling LWC Without APCall Transfer/Conference Audio Information Exchange Audix Features Transparency20.AUDIX in a DCS Network Definity PBX ⎜ Feature 22DISTRIBUTED Communications System DCS Distributed Communications System, Issue 3 Administration ConsiderationsDimension PBX Data Connectivity AN Overview Communications Protocols Data Communications VariablesDigital PBX Public Switched Network Pooled Modem Synchronous vs. Asynchronous Analog vs. DigitalSimplex vs. Half-Duplex vs. Full-Duplex ∙ ∙ ∙Transmission Speed Parallel vs. SerialType of Communications Channel Creating Switch Packet vs. Circuit SwitchesTransmission Mode Changes and Modem Pools Channel Information Bearer vs. Signaling ChannelsChannel Assignment Dial-up vs. Dedicated Connections Terminal Dialing Special Data FeaturesData Call Setup From a Voice Terminal ⎜Data Services FeaturesComputer Dialing Data Hot LineData Privacy Data ProtectionData Restriction Data Only Off-Premises ExtensionOff-Premises Data-Only Extension Conﬁgurations Data Communications Capabilities 2DATA Communications Capabilities DTE Compatibility DTE ConnectionsProtocol Converters PC/PBX or PC/ISDN Terminal EmulatorsData Modules DCE PossibilitiesVoice Terminal Adjunct Data Modules Standalone Data Modules Data Module CharacteristicsADUs ModemsDTE Connections Dtdm PC/PBX ⎜ PC/PBXADM PC/ISDNModem Pooling Connections DCP TIP-RING 12DTE Connections Data Module LAN Topology Local Area Network ConnectionsLAN Protocol LAN Transmission Media LAN ConnectorsAdvantages of a Communications System in a LAN Environment LAN Type Operating Gateway PC Access to/from LANs That Use Other Operating SystemsLAN System SoftwareLocal Area Network Connections Remote PC Communication Between the LAN and Other Networks ISN CommunicationX.25 Router System Package Type Operating CommunicationsSNA Gateway 12.LAN/SNA Connectivity Communication System as a LAN BackupAPS Access Accunet Packet ServicePublic and Private Data Network Connections Public Data NetworksSDS and Sddn Applications Circuit-Switched Public Data NetworksPublic and Private Data Network Connections MPDM/M1 Public and Private Data Network Connections DTE Mpdm Terrestrial Private Data Network Links Private Data NetworksPrivate Connections Through Accunet T1.5 and T45 MPDM/M1* AMI 28PUBLIC and Private Data Network Connections ⎜AMI Satellite Private Data Network Links Isdn Gateway Telemarketing Host ConnectionsIntegrated Telemarketing Gateway 22.Telemarketing Gateway Conﬁguration For further details, see 34TELEMARKETING Host Connections Data Network Administration 36DATA Network Administration Data Communications Configurations DSC and PSC Connections DSC 4DATA Communications Configurations SNA Node Connections File Transfers Connections Through Public or Private Data NetworksVideo Teleconferencing FAX Transmittal Image Processing8DATA Communications Configurations General Related DocumentsOperation Reference2RELATED Documents Related Documents Administration DimensionSystem 75 and Generic 6RELATED Documents Sales ServiceSystem 85 and Generic 8RELATED Documents Sales 10RELATED Documents Need for Synchronization Synchronization of Digital FacilitiesFigure B-1.Options for Synchronization Synchronization Hierarchy 4SYNCHRONIZATION of Digital Facilities Synchronization of Digital Facilities ∙ DDS System 85 and Generic 2 Synchronization Architecture Figure B-3.Stratum Levels for the Synchronization HierarchyPage Primary ⎜ Indicators Primary Secondary Reference Indicators ⎜ ReferenceRED YEL Good LOS Misf ⎜ Blue REDSystem 75 and Generic 1 Synchronization Architecture System 75 and Generic 1 Synchronization Software Operation Figure B-6.Tone-Clock Synchronizer Nonduplicated, GenericCriteria for Switching Back to the Primary Reference Criteria for Switching to the Secondary ReferenceExternal Synchronization Clock CROSS-CONNECT B25A Cable Output Figure B-9.External-Clock Interface Network Synchronization and Engineering Selecting a Timing Source for the SwitchRule Internal Reference Selection RulesExample for Rule Figure B-13.Proper Use of Backup Facilities Page Figure B-15.Optimal Diverse Routing Figure B-16.Less Than Optimal Diverse Routing Figure B-17.Excessive Cascading Figure B-19.Excessive Synchronization from One Node Rules 2 Through External-Reference Selection RulesMisconception Availability of Synchronization SourcesFact Conclusions on Synchronization Line-Only Mode DS1/DMI-BOS ANN11 or TN767USE of Generic 2 AS a System Clock Reference ISDN-PRI Trunk FacilitiesDMI-MOS ANN35 or TN767 with TN555 Line+Trunk Mode DS1/DMI-BOS ANN35 or TN767 with TN555USE of Generic 1 AS a System Clock Reference Trunk-Mode ISDN-PRI TN767Trunk-Mode Interface ISDN-PRI + Robbed Bit TN767 Line-Only Mode DS1/DMI-BOS TN767Trunk-Mode DS1/DMI-MOS TN767 32SYNCHRONIZATION of Digital Facilities Address Signaling Wire Tie TrunkTrunking Terms and Capabilities Frequently Used TermsAPLT-Advanced Private Line Termination Alerting SignalsAuto or Automatic-incoming Auto or Automatic-outgoingCX Signaling or Composite Signaling Ccsa or Common Control Switching ArrangementCustomer Provided Access Cut-Through Mode of OperationDelay-Dial Incoming Delay-DialDelay-Dial Outgoing Delay-Dial Start-Dial DdsdDesigned Trunks Derived E&M Lead SignalingDial Repeating Tie Trunk Dial-PulseEpscs or Enhanced Private Switched Communications Service Direct AccessLead Signaling or Ear & Mouth Signaling Standard or Type 1A and Type I compatible or Type 1BFX or Foreign Exchange ETN Trunking FacilitiesGlare Glare ResolutionGlare Detection High-Usage Trunk Group Ground StartImmediate Start Immediate Start IncomingIntermediate High-Usage Trunk Group Interdigit Time-outIntermachine Trunk IMT Intertandem TrunkParty Test Signal Out-of-Band SignalingMain PBX Main-Satellite TrunksSF or Single Frequency signaling Reverse BatterySenderized Mode of Operation Signal ConverterSpecial Access Connections Signaling TypeStop-Go Signaling Supervisory SignalingTrunk Type or trunk group type Touch-Tone SignalingType of Dialing Type of OutpulsingWink-Start Incoming Wats Wide Area Telephone Service TrunkWink-Start Outgoing Suggestions and Helpful Hints Signaling Types Trunking Characteristics TableSupervision Signaling Tion Generic Switch aSystem 85, or Dimension PBX ⎜GROUP/CALL TypeGROUP/CALL Type Switch B23/FX-DOD OUT DODIN/DID GROUP/CALL Type Signaling 27/WATS OUT 26/WATS28/WATS-DOD OUT ⎜⎜ E&M 35/TIE ESS 5ESS ⎜OTHER ⎜ LS ⎜ RB ⎜ System 85, or ⎜DIMENSION PBX ⎜ Main Satellite ⎜57/CAS RLT-OUTGOING From Branch ⎜66/CAS RLT-INCOMING⎜DIAL-TONE with Line Side 104/HOST Access Digital Data ⎜DATA Module Side 103/HOST AccessAnalog Data Modem Side Trunk SideOther 32TRUNKING Terms and Capabilities Communications Protocols Physical Layer OSI ModelData-Link Layer Network LayerPage Figure D-1.OSI Reference Model Presentation Layer Session LayerApplication Layer Standard ProtocolsTable D-1.Some Ccitt Digital Standards Ccitt X.26 RS-423A FED-STD Table D-2.Some Ccitt Analog StandardsTable D-2.Some Ccitt Analog Standards CCITT-ISO Other Common StandardsEIA AT&T ProtocolsDigital Multiplexed Interface Data Mode CapabilitiesData Modes Description ApplicationsControl Data DCP DS1/DMI/BOS Channel 14COMMUNICATIONS Protocols Communications Protocols Flag Digital Communications Protocol Or multipoint BX.25 Communication Pathways and Endpoints Sldh Message, Packet, and FrameLead Definitions SCB SCFSBA SBBCH/CI RL/CGSTA SDARDA RSAACR DPRCRQ PNDBBB BBADDA DDB⎜ PIN 8LEAD Definitions Networking FEATURES--AVAILABILITY Matrix ⎜⎜ R1 Networking FEATURES--AVAILABILITY Matrix Contd ⎜ NA ⎜ Uniform Numbering ⎜ Plan Note 6NETWORKING FEATURES--AVAILABILITY Matrix Abbreviations CSM CRCCSU DACETN ETAFAX FEPMS/T MpdmMtdm NCPSMT SDNSNA TehoAB-6ABBREVIATIONS ACU GlossaryADM AVDADS Audix Standalone Also high-volume tandemAutomatic Alternate Routing AARBipolar signal Service BccosBit-oriented signaling Message-oriented signalingCcitt BSCCPU COR CcisCOS CPESee data communications equipment See network channel-terminating equipmentDCP DCS Dciu linkDCS cluster DCS node See bit rateDDD DDCSee digital telephone DMI-MOS DCS DMI-BOSDMI/MOS DS1ESS electronic switching Error-free secondCommunications systems and switch Framing format Extended trunk accessBX.25 DCIU/PI Hdlc LAN Lapd Keyboard dialing Kilo bits per second kbpsSee basic rate interface See primary rate interface Local area network LAN Listed directory numberAlso wide area network Local exchange companyNAU NctePAD PDM PVCRemote access trunk 921, and signaling system numberRobbed-bit signaling Protocol converter PCSdlc TDM UNP UCDTelecommunications Service Service Wats trunkWats Wide Area TelecommunicationsIndex IN-2 Index Bypass access trunk 1-37,4-7,4-8,5-1,5-4,C-2ARS 2-4,2-7,2-8,2-14plan Logical 6-3,D-19restricted 1-20unrestrictedCRC 1-25CSMA/CD 8-13CSU Dial access code 2-2,2-5,2-10,2-13,2-17,3-1,4-4Channel bank 1-9,1-10,1-29,1-30,B-20frame DAC 2-2,2-5,2-10,2-13,2-17,3-1,4-4,4-7,4-8,4-9,6-236digitizer Mode 1-15,1-16,1-42,2-13,9-1MOSDMI 1-14, D-11 DS1-ContdESF 1-24, 1-27 D4 1-24, 1-27FRL 2-10, 2-13 Gateway 7-2LOS B-9,B-13 LWC 6-18,6-21,6-24 Statistical 1-17,1-18,1-34DCS 1-36,2-3,5-14 ETN 1-36,2-2,2-8,3-1,4-1,5-1,6-1PCM 1-5,1-7,1-14,1-18,B-1 PAD 7-2,8-21Analog 1-7,9-2trunk DS1 1-13,1-16,1-18Physical layer 1-11,1-15,D-2,D-9 RS-232C1-13,D-9PRI 1-13, D-11 RS-232C1-13,6-3Subnet trunking 2-11, 2-14, 4-9 RNX 2-101-39, C-3, C-5, C-6 Intelligent main 2-4, 4-4, 4-7T1 carrier 1-6,1-18,1-32 Analog 1-3,7-2,7-4 Bypass access 1-37,4-7,4-8,5-1,5-4TCM 2-11,6-23 ﬁnal 5-2,C-9Analog 1-9 Uniform dial plan 2-5, 2-8, 2-9Uniform numbering 2-8, 5-1, 5-5 Auxiliary 1-10, 1-35IN-12 Index