Raj JainThe Ohio State University1ISDNISDNISDNRaj JainProfessor of CISThe Ohio State UniversityColumbus, OH [email protected]://www.cis.ohio-state.edu/~jain/Raj JainThe Ohio State University2q Historyq Interfaces and protocol layersq Reference pointsq AddressingOverviewRaj JainThe Ohio State University3Integrated Digital Networks (IDN)Integrated Digital Networks (IDN)Integrated Digital Networks (IDN)q Integrated ⇒ Both transmission and Switchingq Access was still analogAnalogSwitchFDMFDMAnalogSwitchFDMFDMAnalogSwitch(a) NonintegratedDigitalSwitchTDMPCMDigitalSwitchDigitalSwitch(b) IntegratedTDMPCMRaj JainThe Ohio State University4Integrated Service Digital NetworkIntegrated Service Digital NetworkIntegrated Service Digital Networkq Past: IDN = Integrated Digital Network ⇒ Standardizeddigital techniques for switching and transmission (T1 etc)q 1980: ISDN ⇒ Integrated access to all services ⇒ Digitalend-to-end (Digital subscriber loop)q A single set of interfaces for all services at multiple speedsq Supports voice, data, videotexq Supports both circuit switching and packet switchingq Out-of-band signalingq Sophisticated network management and maintenance usingSignaling System 7 (SS7)q Layered protocol architectureRaj JainThe Ohio State University5HistoryHistoryHistoryq 1968: Study Group D set by CCITT to study digital voiceq 1972: G.702 Integrated digital switching and transmission(IDN) conceptq 1976: Digital switching and signaling (SS7) specq 1980: G.705 - One page recommendation on ISDNq 1984: First set of standards in 1984.Inconsistent and incomplete.q 1988: Revised set of standards. Implementation feasible.q 1992: Additional revisionsRaj JainThe Ohio State University6ISDN ArchitectureISDN ArchitectureISDN Architecturenon-switched⇒ dedicated⇒ PermanentTE NTISDNSwitchSubscriberorProvider>64 kbpsnonswitched>64 kbpsswitched64 kbps ckt nonswitched64 kbps ckt switchedX.25PacketswitchingFrame ModeCCSISDNSwitchUser-NetworksignalingUser-NetworksignalingNetworkSubscriberPremisesPossibly ATMRaj JainThe Ohio State University7ISDN ChannelsISDN ChannelsISDN Channelsq B: 64 kbps for data or voiceq D: 16 or 64 kbps for signaling or packet switched dataq H: 384 kbps (H0), 1536 kbps (H11), 1920 kbps (H12)Raj JainThe Ohio State University8q Basic Rate Interface (BRI): 2B + D = 2 × 64 + 16 = 144 kbps(192 kbps total)q Primary Rate Interface (PRI): For LANs or PBXq 23 B + D = 23 × 64 + 64 = 1.544 Mbpsq 30 B+ D = 30 × 64 + 64 = 2.048 Mbps = 5H0+D (Europe)ISDN Access InterfacesISDN Access InterfacesISDN Access InterfacesPRIBBDBRIBBBBBDRaj JainThe Ohio State University9Other PRI InterfacesOther PRI InterfacesOther PRI Interfacesq PRI H0:q 3H0+D or 4H0 = 1.544 Mbpsq 5H0+D = 2.048 Mbpsq PRI H1:q One H11 in 1.544 Mbpsq One H12 in 2.048 Mbpsq PRI for Mixture of B and H0:q 0 or 1 D and any combination of B and H0, e.g.,3H0+5B+D or 3H0+6B for 1.544 MbpsRaj JainThe Ohio State University10ISDN Functional GroupingsISDN Functional GroupingsISDN Functional Groupingsq Terminal Equipment 1 (TE1): ISDN terminalq Terminal Equipment 2 (TE2): Non-ISDN terminal, e.g.,POTq Terminal Adapter (TA): Allows non-ISDN devices onISDNq Network Termination 1 (NT1): Physical layer device.Separates user premises from phone company. Owned byuser in USA. Owned by PTT in many countries.q Network Termination 2 (NT2): OSI layers 2-3, e.g., PBX,LANq Network Termination 1,2 (NT12): NT1 and NT2 combinedRaj JainThe Ohio State University11Functional GroupingsFunctional GroupingsFunctional Groupingsq NT1:q Physical and electrical terminal of ISDN on user's premisesq Isolates the user from the transmission technology of thesubscriber loopq Line maintenance functions such as loopback testing andmonitoringq Bit multiplexes various B and D channelsq Supports multi-drop lines ⇒ Telephone, personal computer,and alarm on one NT1q NT2:q Digital PBX, LAN, Terminal controllerq Switching and concentrationRaj JainThe Ohio State University12ISDN Reference PointsISDN Reference PointsISDN Reference Pointsq Rate (R): Between Non-ISDN and Terminal Adapter.Uses X or V series recommendations.q System (S): Between ISDN equipment and NT2.Separates user equipment from switching equipment.q Terminal (T): Between NT2 and NT1.Separates network from user.q User (U): Between NT1 and Provider.U interface not defined by ITU.Defined in North America since NT1 owned by user.TE1TE2TE1 or TE2+TATA NT2 NT1NT12NT2 NT1RSTURaj JainThe Ohio State University13ISDN Protocol Reference ModelISDN Protocol Reference ModelISDN Protocol Reference Modelq Similar to OSI 7-layer modelq Separate user, control, and management planesq Control = signalingq Management = network diagnosis, maintenance, and operationPhysical MediumControl UserManagement234675Raj JainThe Ohio State University14ISDN Protocols at UNIISDN Protocols at UNIISDN Protocols at UNIEnd-to-end user signalingQ.931LAPDI.430 basic interface + I.431 Primary interfaceApplicationPresentationSessionTransportNetworkDatalinkPhysicalControlSignalingPacketCktswitchedSemipermanentPacketSwitchedX.25packetI.465/V.120 LAPBX.25packetD Channel B ChannelRaj JainThe Ohio State University15LAPDLAPDLAPDq Link Access Protocol for D Channelq Similar to HDLC and LAPBq X.25 packets are transmitted in LAPD framesq LAPD used for signaling messagesRaj JainThe Ohio State University16ISDN ServicesISDN ServicesISDN ServicesSix types of servicesq Circuit switched calls over a B or H channelq Semipermanent connections over a B or H channelq Packet switched calls over a B or H channelq Packet switched calls over a D channelq Frame relay calls over a B or H channelq Frame relay calls over a D channelRaj JainThe Ohio State University17ISDN AddressingISDN AddressingISDN Addressingq E.164 numbering designed for ISDN allows up to 15 digits= Superset of E.163 numbering plan for telephony (12 digits)q Country code: 1 to 3 digitsq National Destination Code: Provider ID or Area codeq ISDN Address= ISDN number + ISDN subaddress (40 digits max)CountryCodeNationalDestinationCodeISDNSubscriberNumberISDN Subaddress(Max 40 digits)National ISDN NumberInternational ISDN Number (max 15 digits)ISDN Address (max 55 digits)Raj JainThe Ohio State University18q X.121 Data NetworksOther Addressing StructuresOther Addressing StructuresOther Addressing StructuresZone Network terminal numberData country code National numberCountry code National significant number9Telex destination code National telex number8Initial domain identifierDomain specific