1Chapter 7GPRS GPRS System Overview2GPRS GPRS 3GPRSGPRSGPRS4GPRS GSM GSM 1999 GPRS 3GPP http://www.3gpp.org5Section 7.1GPRS Introduction to GPRS 6GPRS (1/2)GPRS GSM 8 Channel Coding SchemesCS1CS2CS3CS49.05kbps171.2 kbps7GPRS (2/2)fast reservation0.5 1 GSM8Section 7.1.1GPRS GPRS Architecture 9GPRS GSM BSSMSC/VLR HLR Serving GPRS Support NodeSGSNGateway GPRS Support NodeGGSN SGSN GSM MSCGPRS GGSN GGSN107-1GPRS GSMCircuit-switched service (CS) domainPacket-switched service (PS) domain11GPRS (1/2)BSS Um BSS SGSN Gb GPRS SGSN GGSN Gn SGSN GGSN GPRS SGSN GGSNGp 12GPRS (2/2)GGSN Gi MSC/VLR GPRS BSS GSM A SGSN Gs HLRGr GcSGSN GGSN Gr Gc GSM MAP 13SGSN (Ericsson)147-2GPRSBSSUmSGSNGbGGSNGnGi GPRS GGSNGpSGSNGnMSC/VLRHLRDAGsGcGrCGFBilling SystemGaGaSMS-GMSC/SMS-IWMSCGdE CSignaling InterfaceSignaling and Data Transfer Interface15GPRS protocol stack transmission plane signaling planeGPRS 16Section 7.1.2GPRS GPRS Transmission Plane 177-3GPRS BTSUmSGSNApplicationIP/X.25SNDCPLLCRLCMACGSM/GPRS RFMSGSM/GPRS RFMACRLCRelayBSSGPNSLayer 1BSSRelayIPLayer 2Layer 1SGSNBSC/PCULayer 1NSBSSGPLLCSNDCP GTPUDP/TCPGb Frame Relay IP/X.25IPLayer 1GGSNLayer 2UDP/TCPGTPGnGiGGSN18MACRLCLLC Medium Access Control LayerMAC frameRadio Link Control LayerRLC Logic Link Control LayerLLC SGSNGPRS 19SNDCP SubNetwork Dependence Convergence ProtocolSNDCP GPRS Segmentation and ReassemblySAR-- N-PDUSN-PDULLC LLC SNDCPLLCN-PDU TCP/IP V.42bis 20BSSGPBase Station Subsystem GPRS Protocoldownlink SGSN BSS RLC/MAC MS radio access capabilityQoS profilePDU PDU lifetimeuplinkBSS SGSN RLC/MAC 21GTP (1/2)GPRS GPRS Tunneling ProtocolGTPGPRS GSN GGSN PDU GTP GTP PDUtunnelSGSN GSN -- Tunnel IDTID GSN path22GTP (1/2)GGSN IPTID IP TID TID GGSN SGSNSGSN GTP PDU PDU23GPRS Example 1SGSN 1 SGSN 2BSCBTSBSCBTSGPRS networkMS 1MS 224GPRS Example 2SGSN 1GGSN 1SGSN 2GGSN 2BSCBTSBSCBTSGPRS network 1 GPRS network 2Packet data network or InternetMS 1MS 225GPRS Example 3SGSN 1GGSN 1BSCBTSGPRS network 1Packet data network or InternetMS 1DHCP Server26Section 7.1.3GPRS GPRS Signaling Plane 277-4GPRSBTSUmSGSNGMM/SMLLCRLCMACGSM/GPRS RFMSGSM/GPRS RFMACRLCRelayBSSGPNSLayer 1BSSRelayIPLayer 2Layer 1SGSNBSC/PCULayer 1NSBSSGPLLCGTPUDPGb Frame Relay GnGcGGSNGMM/SMInternetworkingMTP3Layer 1GGSNLayer 1SCCPIPUDPGTPLayer 2 MTP2TCAPMAPHLRMTP3Layer 1SCCPMTP2TCAPMAPHLRGsSGSNSGSN MSC/VLRMSC/VLRBSSAP+SCCPMTP3MTP2Layer 1BSSAP+SCCPMTP3MTP2Layer 1GrSGSNSGSN HLRHLRTCAPSCCPMTP3MTP2Layer 1TCAPSCCPMTP3MTP2Layer 1MAP MAP28GMM / SM (1/2)PS domain Mobility Management Session ManagementMobility Management GPRS GPRS Mobility ManagementGMM Mobility Management contextMM context AttachDetachRouting Area UpdateSecurity29GMM / SM (2/2)Session Management Session ManagementSM Packet Data Protocol contextPDP Context PDP Context ActivationDeactivationPDP Context Modification Quality-of-service (QoS) profile30Gs / Gr / Gf BSSAP+SGSN VLR/HLR/EIR Gs/Gr/Gf MAP GSM TCAPSCCPMTPBSSAP+ IMSIGPRS GSM MSC/VLR SGSN GSM GPRS location areaVLR/HLR/SGSN 31GTPGPRS GSN GTP GTP path management tunnel management location management mobility management32Section 7.1.3GPRS GPRS Area Planning 33GPRS GPRS Routing AreaRARouting Area IdentityRAI RAI GPRS RAI RAIRA34GPRS Routing Area 1Location Area 1 Location Area 2Routing Area 2Routing Area 335CS PS CS domain location areas (LAs) LA VLR PS domain routing areas (RAs) RA LA RA SGSN MS SGSN SGSN MS cellRARARALA36Section 7.1.4MM Context PDP Context 37GPRS GPRS GPRS GPRS GPRS GMM / SM 38(1/2)GPRS MSGPRS-attach GPRSGPRSGPRS-detachGPRS always on39(2/2)always on GPRSMobility ManagementMM MS RA 40(1/2)GGSN logic address IPIP GPRSPDPPacket Data Protocol addressPDP address41(2/2)PDP radio priorityPDP contextPDP contextPDP context activationPDP contextSGSN GGSN PDP contextPDP context 427-6MM state SessionReady Standby Ready Standby ReadyPDP context Activation PDP context DeactivationSessionReady Standby Ready Standby ReadyPDP context Activation PDP context Deactivation43MM ContextGPRS SGSN MM ContextMM stateidle statestandby stateready state447-5IdleReadyStandbyIdleReadyStandbyGPRS Attach GPRS Detach GPRS AttachPDU transmissionReady timer expiryForce to StandByImplicit DetachCancel LocationPDU receptionGPRS DetachCancel LocationReady timer expiryForce to StandByAbnormal RLC conditionSGSNDetach45PLMN GPRSGPRS SGSN PTM-MPoint to Multipoint -Multicast PTM-GPoint to Multipoint Group Call SGSN /attach46(1/2)SGSN RA cell GPRS SGSN PTM-M PTM-G 47(2/2)SGSN MM Context GPRS SGSN RLC SGSN MM Context SGSN HLR Cancel LocationSGSNMM ContextPDP Context48(1/2)GPRS SGSN MM Context GPRSRA PTM-M/PTM-G GSM SGSN PTM-G detach49(2/2)mobile reachable timerSGSN SGSN GGSN PDP Context SGSN MM Context PDP Context 50PDP Context (1/2)GPRS PDP Context GPRS SGSN GGSN PDP Context GPRS GPRS PDP Context MM Context51PDP Context (2/2)GPRS PDP PDP address IPv4IPv6X.25 PDP GPRS PDP PDP statePDP PDP INACTIVE ACTIVE527-7PDP INACTIVEACTIVEActivate PDP ContextDeactivate PDP ContextMM state change to IDLE53PDP MS PDP Context PDP Context GGSN GGSN PDP ContextNetwork-Initiated PDP Context ActivationPDP PDP ContextMS-InitiatedPDP Context ActivationPDP 54PDP Context PDP SGSNGGSN MM Context SGSN SGSN BSS RASGSN55PDP ContextGPRSPDP Context PDP Context Deactivation ProcedurePDP MM State PDP MM State PDP 56PDP Context APNAccess Point NameGGSNQoS profilePDP ContextSGSN GGSN PDP ContextPDP PDP TypeIPPPP IPv6QoS Requested 57MM ContextPDP Context QoS Profile MM ContextPDP ContextQoS ProfilePDP ContextQoS ProfilePDP ContextQoS Profile58GPRS MS MM and PDP ContextsFieldSIMDescriptionIMSI International Mobile Subscriber Identity.MM State Mobility management state, IDLE, STANDBY, or READY.P-TMSI Packet Temporary Mobile Subscriber Identity.P-TMSI Signature A signature used for identification checking purposes.Routeing Area Current routeing area.Cell Identity Current cell.Kc Currently used ciphering key.CKSN Ciphering key sequence number of Kc.Ciphering algorithm Selected ciphering algorithm.Classmark MS classmark.DRX Parameters Discontinuous reception parameters.Radio Priority SMS The RLC/MAC radio priority level for uplink SMS transmission.Each MM context contains zero or more of the following PDP contexts:PDP Type PDP type, e.g., X.25, PPP or IP.PDP Address PDP address, e.g., an X.121 address.PDP State Packet data protocol state, INACTIVE or ACTIVE.Dynamic Address Allowed Specifies whether the MS is allowed to use a dynamic address.NSAPI Network layer Service Access Point Identifier.TI Transaction Identifier.QoS Profile Requested The quality of service profile requested.QoS Profile Negotiated The quality of service profile negotiated.Radio Priority The RLC/MAC radio priority level for uplink user data transmission.59Section 7.2GPRS GPRS Radio Interface 60GPRS GPRS GSM GPRS GPRS 61Section 7.2.1GPRS GPRS Logic Channels 62GPRS GPRS Packet Data CHannelPDCHGPRS logic channel PDCH traffic channelscontrol channels637-8GPRS PDCHPCCCHPhysical ChannelPBCCHPDTCHPDCCHPPCHPRACHPAGCHPNCHdownlink onlyuplink onlydownlink onlydownlink onlydownlink onlyPACCHPTCCH/UPTCCH/D64Traffic ChannelPDTCHPacket Data Traffic Channel PDTCH PDTCHPDTCH PDTCH 65Control Channels Packet Broadcast Control CHannelPBCCHGPRS Packet Common Control CHannelPCCCH Packet Dedicated Control CHannelPDCCH66PCCCHPRACH PCCCHPPCH GPRSPAGCHGPRSPNCH GPRS PTM-M PTM-M 67PDCCH (1/2)PACCHPacket Associated Control Channel acknowledge PACCH PDTCH PDTCH PACCH 68PDCCH (2/2)PTCCH Timing AdvanceTABTS PTCCH/UPacket Timing advance Control CHannel/UplinkPTCCH/U BTS BTS PTCCH/DPacket Timing advance Control CHannel/DownlinkBTS TA MS 69Section 7.2.3GPRS GPRS Uplink Data Transfer and Paging707-9GPRS MS NetworkPacket Channel RequestPacket Uplink AssignmentPRACHRACHPAGCHAGCHPacket Resource RequestPacket Uplink AssignmentPACCHPACCHpacket channel request PRACH/RACHGPRS PAGCH/AGCH 71MS (1/2)one phasePRACH RACH Packet Channel RequestGPRSMS PDCH 72MS (2/2)Packet Uplink Assignment RACH MS MS PACCH Packet Resource Request GPRS 737-10GPRS MS NetworkPacket Paging RequestPaging RequestPacket Channel RequestChannel RequestPPCHPCHPRACHRACHPacket Uplink AssignmentImmediate AssignmentPacket Resource RequestPAGCHAGCHPACCHPacket Uplink AssignmentPacket Paging ResponseLLC framePACCHPDTCHRA PPCH74PPCHPRACH PAGCH PCHRACH AGCH 7-9 Packet Resource Request Packet Uplink Assignment75Section 7.3GPRS GPRS High Level Communication Procedure 76GPRS GPRS GPRS location update procedureSGSN GPRS GPRS GPRS attach and detach procedureGPRS GPRSGPRS PDP context procedureGGSN77Section 7.3.1GPRS GPRS Location Update78PS domain MS RA SGSN RA SGSNRAIntra-SGSN Routing Area UpdateSGSN SGSN SGSNRAInter-SGSN Routing Area Update2 SGSNGGSNHLR Periodically Routing Area UpdateMS RA797-11SGSN (1/2)BSSNewSGSNOld SGSN GGSNNew MSC/VLR1. Routing Area Update Request2. SGSNContext Request3. SGSN ContextResponse4. Security FunctionsHLR5. SGSN ContextAcknowledge6. Forward packets7. Update PDP Context Request8. Update PDP Context Response9. Update Location10. Cancel Location10. Cancel Location ACKOld MSC/VLR807-11SGSN (2/2)BSSNewSGSNOld SGSN GGSNNew MSC/VLRHLROld MSC/VLR10. Cancel Location10. Cancel Location ACK11. Insert Subscriber Data11. Insert Subscriber Data ACK12. Update Location ACK13. Location Update Request14. Inter-VLR Location Update15. Location Update Accept16. Routing Area Update Accept17. Routing Area Update Complete18. TMSI Reallocation Complete81SGSN (1/7)1. Routing Area Update Requestnew SGSN old RAIRouting Area IdentitySGSN P-TMSI Update TypeRA/LA Update2. old RAInew SGSN old SGSN New SGSN SGSN Context Request new SGSN IP GTP P-TMSI82SGSN (2/7)3. Old SGSN P-TMSI new SGSNSGSN Context ResponsePDP contextMM context IMSIPDP Context GTP PDU APNGGSN MM Context Authentication Triplets PDU new SGSN 4. old SGSN HLR 83SGSN (3/7)5. new SGSN old SGSN SGSN Context Acknowledge PDP Context SGSN 6. Old SGSNnew SGSN7. New SGSN Update PDP Context Request GGSNGGSN SGSN GGSN PDP Context 84SGSN (4/7)8. GGSN Update PDP Context Response new SGSNGGSN new SGSN 9. New SGSN Update Location HLRHLR new SGSN10. HLR MAP Cancel Location old SGSNold SGSN PDP ContextSGSN Cancel Location ACK HLR85SGSN (5/7)11. HLR Insert Subscriber Data SGSNSGSN Routing AreaRASGSN MM ContextInsert Subscriber Data ACK HLR12. HLR Update Location ACK SGSN 86SGSN (6/7)13New SGSN Location Update Request new VLR new SGSN 14VLR GSM HLR VLR old VLR 15New VLR TMSI Location Update Accept new SGSNTMSI new SGSN87SGSN (7/7)16SGSN PDP Context MM ContextRouting Area Update Accept TMSI 17Routing Area Update Complete new SGSN N-PDU N-PDU18New SGSN TMSI Reallocation Complete VLRTMSI88Section 7.3.2GPRSGPRSProcedures of GPRS Attach and Detach897-12GPRS BSSNewSGSNOld SGSN GGSN HLR1. Attach Request2. IdentificationRequest3. IdentificationResponse4. Authentication5. Location Update6. Attach Accept7. Attach Complete(old-PTMSI, old SGSN)(old-PTMSI)(old-PTMSI)(newP-TMSI)Um Gb Gn90GPRS (1/2)SGSN 1. Attach Request SGSN IMSI P-TMSI2. New SGSN P-TMSInew SGSN Identification Request oldSGSNIMSI3. Old SGSN Identification ResponseIMSI SGSN91GPRS (2/2)4. MM Context5. RA LA UpdateNewSGSN Update Location Request HLR6. New SGSN Attach Accept SGSN P-TMSI 7. new SGSNAttach Complete92MS-Initiated Detach GPRSGPRS detach Network-Initiated Detach GPRSGPRS detachHLRHLR-Initiated Detach GPRSHLR SGSN 937-13GPRS BSS SGSN GGSN HLR VLR1. Cancel Location3. Delete PDPContext Request6. Detach Accept7. Cancel Location ACK2. Detach Request4. Delete PDPContext RequestReponse5. GPRS Detach IndicationUmGb Gn Gr DGr: in GSM MAPin GMM layerin GTP layerGs: in BSSAPT layerin GMM layer94GPRS (2/2)HLR GPRS 1. HLRCancel Location SGSN2. SGSN GPRS Detach Request3.4. SGSNDelete PDP Context Request GGSN PDP contextGGSNDelete PDP Context Response95GPRS (2/2)5. SGSN GPRS Detach Indication VLRSGSN6. SGSNGPRSDetach Accept7. SGSN MM context PDP contextCancel Location AckHLR96Section 7.3.3GPRSGPRS PDP Context Procedures97PDP Context PDP Context Activation MS-Initiated Network-InitiatedGGSN PDP PDU GGSN PDP PDP Context PDP ContextGGSN PDP Context PDP Context ModificationPDP Context Deactivation SGSN-initiated MS-initiated GGSN-initiated987-14GPRS PDP context BSS SGSN GGSN1. Activate PDP Context Request2. Create PDPContext Request3. Create PDPContext RequestResponse4. Activate PDP Context AcceptSNDCP PDUTLLINSAPIPDP PDUExternalnetworkGTP PDUTIDPDP PDUPDP PDUPDP AddressData Transmission/Receivein GMM (APN, QoS...)Gn:in GTP layer(IP address...)(IP address, negotiated QoS...)99GPRS PDP Context (1/3)1. Activate PDP Context Request SGSN PDP type, PDP address, APN, QoS profile 2. SGSN GGSN100GPRS PDP Context (2/3)3. GGSN SGSN GGSN GGSN GGSNPDP Context IP GGSN IP GGSN SGSN Create PDP Context Response IP GGSN 101GPRS PDP Context (3/3)4. SGSN GGSN IP PDP Context SGSN Activate PDP Context Accept PDP Context Deactivate PDP Context APN 102PDP Context GGSN SGSN PDP contextPDP context GPRS negotiated QoSradio priorityPDP Traffic Flow TemplateTFT7-15 SGSN PDP context SGSN-Initiated PDP Context Modification Procedure1037-15SGSN PDP Context BSS SGSN GGSN1. Update PDP Context Request3. Modify PDP Context Request2. Update PDP Context Response4. Modify PDP Context Response1047-16PDP ContextBSS SGSN GGSN1. Deactivate PDP Context Request2. Delete PDP ContextRequest3. Delete PDP ContextResponse4. Deactivate PDP Context Accept105Section 7.3.4GPRSGPRS Billing106GPRS (1/2)GPRS SGSN GGSN SGSN GGSN Call Detailed RecordCDRCharging Gateway FunctionCGFSGSN GGSN Billing SystemBS107GPRS (2/2)CDR CDR CDR SGSN CDRInter-SGSN Routing Area Update1087-17GPRS GfDGiGn GbGcC EGpGsSignalling and Data Transfer InterfaceSignalling InterfaceMSC/VLRTE MT BSS TE PDNR UmGrAHLROther PLMNSGSNGGSNGdSM-SCSMS-GMSCSMS-IWMSCGGSNEIRSGSNGnCGFBillingSystemGaGa109GPRS SGSNGGSNBSCBTSMS 1Service ApplicationMSCPLMNMSCCGFGPRS Billing MediationBilling SystemBilling recordsBackbone networkCGF: Charging Gateway FunctionCDR: Charging Data Record110SGSN SGSN PDP GPRS 111GGSN GGSN SGSN PDP 112(1/2)GPRSCDRS-CDRG-CDRM-CDRS-SMO-CDR S-SMT-CDRS-CDR SGSN IMSISGSNcharge identifierGGSNAPNAPNPDPPDPSGSNG-CDR GGSN IMSIGGSNSGSNAPNPDPPDPGGSN113(2/2)M-CDR SGSN IMSISGSN RALA S-SMO-CDR SGSN IMSISGSN E.164SGSN S-SMT-CDR SGSN SGSN S-SMO-CDRSGSNSGSN114GPRS : GSMGPRS PDP context GSM GPRS CDR GPRSCGFSGSNs/GGSNs 115Section 7.4Summary116SummaryGPRS3Gbursty and bulkyradio resource on demandalways onvolume-dependent charging3GB3Gbeyond 3G117Homework1 (1)-1(10),1,3,5,7,9118APN (Access Point Name)Access Point Name is a label according to DNS naming conventions describing the access point to the external packet data network. An APN is the logic way to name a GPRS service.Domain Name Service (DNS) server translates APN to GGSNs IP address.119Access a GPRS Service with an APNMobile user activates a service.MS sends request to SGSN (including APN).SGSN check whether the service has be authorized for this user.SGSN acquires the IP address of this specific GGSN (for the APN) from DNS server.A tunnel is created between SGSN and GGSN.120IP Address AllocationFixed Addressing IP address is stored in HLR. It is sent to MS when MS wants to send data.Dynamic Addressing GGSN gets an IP address. GGSN assigns an address to MS.121Mechanism to Get IP AddressFrom a local address pool on the GGSNVia DHCPVia RADIUS from an external RADIUS serverFrom the customer network via an L2TP tunnel from the GGSN