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Chapter 7GPRS
GPRS System Overview
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GPRS GPRS
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GPRSGPRSGPRS
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GPRS
GSM
GSM
1999 GPRS 3GPP http://www.3gpp.org
GPRS GSM , packet-switched.
end-to-end packet-switched.GPRS 1994 ETSI/SMGthe European Telecommunications Standards Institute / Special Mobile Group.GPRS 1997 SMG#25 (25SMG), , 1999 .
GPRS , GSM , IS-136. , GPRS IS-136 . GPRS core network 3G .GPRS circuit-switching : data burst , asymmetric (up/down ), GSM circuit-switching , data transfer rate , call setup access time , data data .
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Section 7.1Section 7.1GPRS Introduction to GPRS
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GPRS (1/2)
GPRS GSM
8 Channel Coding
SchemesCS1CS2CS3CS49.05kbps171.2 kbps
GPRS BS, . packet, logic radio channel, packet .
GPRS , channel , , .
timeslot packet , carrier 8 timeslots MS.
2003, 5 timeslots data, 3 downlinks 2 uplinks)
, timeslot, MS . capacity on demand , . channel, uplink downlink , Web, file transfer asymmetric flow . Channel coding schemes, CS1, CS2, CS3, CS4, 9kbps 150 kbps . coding , , coding. fast reservation , 0.5 1 sec . user GPRS 1 sec , resource access data. GPRS GPRS attached, always on line. data burst , .
GPRS GSM . packet data . GPRS SMS Circuit-switched .
SMS GPRS channel .
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GPRS (2/2)
fast reservation 0.5 1 GSM
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Section 7.1.1Section 7.1.1GPRS GPRS Architecture
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GPRS
GSM BSSMSC/VLR HLR Serving GPRS Support NodeSGSNGateway GPRS Support NodeGGSN SGSN GSM MSCGPRS
GGSN GGSN
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7-1 GPRS GSM
GSM
BSS
HLR
MSC/VLR GMSC/VLR
SGSN GGSN
GPRS
PSTN
PDN
PDU
Circuit-switched service (CS) domain
Packet-switched service (PS) domain
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GPRS (1/2)
BSS Um BSS SGSN Gb GPRS SGSN GGSN Gn SGSN GGSN GPRS SGSN GGSN Gp
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GPRS (2/2)
GGSN Gi MSC/VLR GPRS BSS GSM A SGSN Gs HLRGr Gc SGSN GGSN Gr Gc GSM MAP
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SGSN (Ericsson)
SGSN solutionLucents solution supports 40,000 attached users and 4,000 simultaneous active GPRS data sessions.Nortels Passport 8380G and Symmetrys UWS-GMS support 50,000 attached users and 20,000 simultaneous active GPRS data sessions.Alcatels SGSN supports 52,000-96,000 attached users.
GGSN solution GGSN .Alcatel GGSN Cisco 7200 .Nokia GGSN Nokia IP routing . GGSN 5000 48000 , 25000 48000 attached GPRS .
SGSN, Ericsson . SGSN 25,000 PDP, 10,000 packet/sec. GGSN 35,000 PDP, 15,000 packet/sec. SGSN 100,000 PDP, 40,000 packet/sec. GGSN 150,000 PDP, 60,000 packet/sec. SGSN GGSN CGSN.
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7-2 GPRS
BSS
Um
SGSN
Gb
GGSN
Gn
Gi
GPRS GGSN
Gp
SGSN
Gn
MSC/VLR HLR
D
A
Gs GcGr
CGF Billing System
Ga
Ga
SMS-GMSC/SMS-IWMSC
Gd
E C
Signaling Interface
Signaling and Data Transfer Interface
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GPRS protocol stack transmission plane
signaling plane GPRS
GPRS, OSI 7-layer , interface layered structure. protocol stack : protocol structure transmission plane.
, ,.transmission plane protocol structure signaling plane.
user location update, PDP activate/deactivate, paging user. GPRS, OSI 7-layer , interface layered structure. protocol stack :
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Section 7.1.2Section 7.1.2GPRS GPRS Transmission Plane
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7-3 GPRS
, , , TCP , X.25 IP GPRS .Note: GGSN, SGSN IP
IP IP , GPRS .
GPRS , GPRS , .
IP , GPRS IP static IP, GPRS dynamic host configuration protocol DHCP IP dynamic IPIP virtual IP.
IP GPRS IP , GSN .
GPRS IP , OSI layer 1 L1layer 2 L2, .
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MSCRLCLLC
Medium Access ControlLayerMAC LLC frame
Radio Link ControlLayerRLC
Logic Link Control LayerLLC SGSNGPRS
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SNDCP
SubNetworkDependence Convergence ProtocolSNDCP GPRS
Segmentation and
ReassemblySAR-- N-PDU SN-PDU LLC LLC SNDCPLLC N-PDU
TCP/IP V.42bis
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NS
Network ServiceNSBSS SGSN Frame Relay BSS SGSN (Virtual ConnectionNS-VC) NS BSSGP
BSSGP PDU
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BSSGP
Base Station Subsystem GPRS Protocoldownlink SGSN BSS RLC/MAC
MS radio access capabilityQoS profile PDU PDU lifetime
uplinkBSS SGSN RLC/MAC
PDU PDU BSS BVC SGSN PDU BSS PDU BSS SGSN PDU SGSN BSS SGSN BSSGP
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GTP (1/2)
GPRS GPRS Tunneling ProtocolGTP GPRS GSN GGSN PDU GTP GTP PDUtunnel SGSN
GSN -- Tunnel IDTID
GSN path
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GTP (1/2)
GGSN IP TID IP TID TID GGSN SGSNSGSN GTP PDU PDU
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Section 7.1.3Section 7.1.3GPRS GPRS Signaling Plane
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7-4 GPRS
GPRS Signaling Plane MS SGSN , GMM/SM layer GPRS session .SGSN GGSN Gn interface Transmission Plane UDP .GGSN HLR Gc interface MAP GSM MAP GPRS .SGSN MSC/VLR Gs interface extended BSSAP, TCAP.
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GMM / SM (1/2)
PS domain
Mobility Management Session Management
Mobility Management GPRS GPRS Mobility Management
GMM Mobility Management contextMM context AttachDetachRouting Area UpdateSecurity
GPRS (mobility management, MM) MM (session management, SM) ( attach) ( detach) ( routing area update) (security)SGSN
(SGSN) MM context MS , MS GPRS , . , MS .
IP address, , MS GPRS
(SGSN,GGSN) PDP context PDP Context Activation IP address PDP Context Deactivation Modification. SGSN GGSN
PDP context (QoS) QoS profile PS domain , package 3
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GMM / SM (2/2)
Session Management Session ManagementSM
Packet Data Protocol contextPDP Context PDP Context ActivationDeactivationPDP Context
Modification Quality-of-service (QoS) profile
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Gs / Gr / Gf BSSAP+
SGSN VLR/HLR/EIR Gs/Gr/Gf MAP GSM TCAPSCCP MTPBSSAP+ IMSI GPRS GSM MSC/VLR SGSN
GSM GPRS location areaVLR/HLR/SGSN
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GTP
GPRS GSN GTP
GTP TCP UDP GTP UDP GTP path management tunnel management location management mobility management
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Section 7.1.3Section 7.1.3GPRS GPRS Area Planning
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GPRS
GPRS Routing AreaRARouting Area IdentityRAI RAI
GPRS RAI RAI RA
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GPRS
Routing Area 1
Location Area 1 Location Area 2
Routing Area 2 Routing Area 3
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CS PS
CS domain location areas (LAs) LA VLR
PS domain routing areas (RAs) RA LA RA SGSN MS SGSN
SGSN MS cell
RARA
RA
LA
MS CS domain PS domain location mobility management
MS CS domain (i.e., GSM MS ) IMSI-attached
LA MS , VLR
MS PS domain , GPRS-attached RA MS MS SGSN MS MS , SGSN cell MS
Why RA?MS network access, paging cells , paging cost ( registration cost ). MS , . page BTS , BTS
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Section 7.1.4Section 7.1.4MM Context PDP Context
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GPRS
GPRS
GPRS GPRS GPRS
GMM / SM
GMM/SM GPRS GPRS PDP Context Activation PDP Context Deactivation
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(1/2)
GPRS MS GPRS-attach GPRSGPRS GPRS-detach GPRS always on
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(2/2)
always on GPRSMobility ManagementMM
MS RA
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(1/2)
GGSN logic address IPIP
GPRSPDPPacket Data Protocol addressPDP address
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(2/2)
PDP radio priorityPDP contextPDP context PDP context activationPDP contextSGSN GGSN PDP context PDP context
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7-6 MM state
Session
ReadyStandbyReady Standby Ready
PDP context Activation PDP context Deactivation
Session
ReadyStandbyReady Standby Ready
PDP context Activation PDP context Deactivation
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MM Context
GPRS SGSN MM Context
MM stateidle statestandby stateready state
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7-5
GPRS Attach GPRS Detach GPRS Attach
PDU transmission
Ready timer expiry
Force to StandBy
ImplicitDetach
CancelLocation
PDU reception
GPRS Detach
Cancel Location
Ready timer expiry
Force to StandBy
Abnormal RLC condition
SGSN
Detach
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PLMN GPRS GPRS SGSN
PTM-MPoint to Multipoint -Multicast
PTM-GPoint to Multipoint Group Call
SGSN
/attach
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(1/2)
SGSN RA cell GPRS SGSN PTM-M PTM-G
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(2/2)
SGSN MM Context GPRS SGSN RLC SGSN MM Context
SGSN HLR Cancel LocationSGSNMM ContextPDP Context
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(1/2)
GPRS SGSN MM Context GPRS
RA PTM-M/PTM-G GSM SGSN PTM-G detach
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(2/2)
mobile reachable timer SGSN SGSN
GGSN PDP Context SGSN MM Context PDP Context
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PDP Context (1/2)
GPRS PDP Context GPRS SGSN GGSN PDP Context
GPRS GPRS PDP Context
MM Context
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PDP Context (2/2)
GPRS PDP PDP address IPv4IPv6X.25 PDP GPRS
PDP PDP state PDP
PDP INACTIVE ACTIVE
IP IP GPRS PDP Packet Data Protocol addressGPRS PDP
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GPRS (2/8)
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7-7 PDP
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PDP MS PDP Context PDP
Context GGSN GGSN PDP ContextNetwork-Initiated PDP Context Activation PDP PDP ContextMS-Initiated PDP Context Activation PDP
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PDP Context PDP SGSNGGSN MM Context SGSN SGSN BSS RASGSN
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PDP Context
GPRS PDP Context PDP Context Deactivation ProcedurePDP
MM State PDP
MM State PDP
GPRS GPRS/ PDP Context PDP Context
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PDP Context
APNAccess Point Name GGSN
QoS profile PDP ContextSGSN GGSN PDP ContextPDP PDP Type IPPPP IPv6QoS Requested
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MM ContextPDP Context QoS Profile
MM ContextPDP Context
QoS Profile
PDP Context
QoS Profile
PDP Context
QoS Profile
MM Context PDP Context QoS Profile PDP Context maintain PDP Context ACTIVATE GPRS QoS Profile negotiated radio network resources
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GPRS MS MM and PDP ContextsField SIM Description
IMSI 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.
SIM card SIM .
IMSI (International mobile subscriber identity) VLR, HLR SGSN, GGSN .P-TMSI (Packet-TMSI, packet temporary mobile subscriber identity) GPRS GSM TMSI ID.RA (Routing Area): MS for GPRS MM.Ciphering key Kc, CKSN (ciphering key sequence number) Kc .P-TMSI Signature.
MM :MM state, Cell Identity, Ciphering algorithm.radio access classmark radio capabilities, multiple time slot capability, power class.SGSN classmark network-related capability, ciphering capability.
PDP context :PDP type, PDP address, PDP state.Dynamic-Address-Allowed MS dynamic address.Requested and negotiated QoS profile.
NSAPI (, )
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Section 7.2Section 7.2GPRS GPRS Radio Interface
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GPRS
GPRS GSM
GPRS
GPRS
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Section 7.2.1Section 7.2.1GPRS GPRS Logic Channels
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GPRS
GPRS Packet Data CHannelPDCHGPRS logic channel PDCH
traffic channelscontrol channels
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7-8 GPRS
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Traffic Channel
PDTCHPacket Data Traffic Channel PDTCH PDTCH
PDTCH PDTCH
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Control Channels
Packet Broadcast Control
CHannelPBCCH GPRS
Packet Common Control CHannelPCCCH
Packet Dedicated Control CHannelPDCCH
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PCCCH
PRACH PCCCH
PPCH GPRS
PAGCHGPRS
PNCH GPRS PTM-M PTM-M
PTM-MPNCH
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PDCCH (1/2)
PACCHPacket Associated Control Channel acknowledge
PACCH PDTCH PDTCH
PACCH
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PDCCH (2/2)
PTCCH Timing AdvanceTA BTS PTCCH/UPacket Timing advance Control
CHannel/UplinkPTCCH/U BTS BTS
PTCCH/DPacket Timing advance Control CHannel/Downlink
BTS TA MS
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Section 7.2.2Section 7.2.2GPRS GPRS Radio Resource Management
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(master-slave) capacity on demand PDCH master PCCCH PDCH slave (PDTCH) (PACCH)GPRS i.e.PDCH
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Section 7.2.3Section 7.2.3GPRS GPRS Uplink Data Transfer and Paging
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7-9 GPRS
packet channel request PRACH/RACH
GPRS PAGCH/AGCH
MS GPRS PRACH packet channel request, packet immediate assignment
, GPRS 11 bits 8 bits packet channel request, . PACCH packet resource requestpacket resource assignmentPDCH
PACCH PRACH
( phase 1) ( phase 2optional)
GPRS PDCH PRACH PAGCHMS GSM RACH AGCHPACCHMS .
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MS (1/2)
one phase PRACH RACH Packet Channel RequestGPRS MS PDCH
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MS (2/2)
Packet Uplink Assignment
RACH MS
MS PACCH Packet Resource Request GPRS
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7-10 GPRS RA
PPCH
, .
PPCH packet paging request PRACH packet channel request PAGCH PACCH PPCHPRACHPAGCHPCHRACHAGCH
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PPCHPRACH PAGCH PCHRACH AGCH
7-9 Packet Resource Request Packet Uplink Assignment
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Section 7.3Section 7.3GPRS GPRS High Level Communication Procedure
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GPRS
GPRS GPRS location update
procedure SGSN
GPRS GPRS GPRS attach and detach procedure
GPRS
GPRSGPRS PDP context procedure
GGSN
GPRS procedures GPRS interface, , . 4 GPRS message flow:
RA/LA Update: GPRS network MS , MS RA/LA location information.GPRS Attach: MS GPRS network GPRS Detach: MS GPRS network PDP context procedure: MS GPRS network , PDP context
procedure , entities interface ( top layer) , , , procedure .
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Section 7.3.1Section 7.3.1GPRSGPRS GPRS Location Update
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PS domain
MS RA SGSN RA SGSNRAIntra-SGSN Routing Area
Update SGSN SGSN
SGSNRAInter-SGSN Routing Area Update 2 SGSNGGSNHLR
Periodically Routing Area Update MS RA
MS location update :Intra-SGSN Routing Area Update
MS SGSN cells , SGSN location . MS Routing Area Update Request SGSN.SGSN Authentication. SGSN RAND MS, MS SRES SGSN, SGSN .SGSN P-TMSI MS.MS Routing Area Update Complete, location update.
Inter-SGSN Routing Area Update MS 2 SGSN, GGSN, HLR, , MS location .
MS routing area updateMS network, .Ex: 45
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7-11 SGSN (1/2)
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7-11 SGSN (2/2)
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SGSN (1/7)
1. Routing Area Update Request new SGSN old RAIRouting Area Identity
SGSN P-TMSI Update TypeRA/LA Update
2. old RAInew SGSN old SGSN New SGSN SGSN Context Request new SGSN IP GTP P-TMSI
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SGSN (2/7)
3. Old SGSN P-TMSI new SGSNSGSN Context Response
PDP contextMM context IMSIPDP Context GTP PDU APNGGSN MM Context Authentication
Triplets
PDU new SGSN
4. old SGSN HLR
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SGSN (3/7)
5. new SGSN old SGSN SGSN Context Acknowledge PDP Context SGSN 6. Old SGSN new SGSN 7. New SGSN Update PDP Context Request GGSN GGSN SGSN GGSN PDP Context
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SGSN (4/7)
8. GGSN Update PDP Context Response new SGSN GGSN new SGSN 9. New SGSN Update Location HLR HLR new SGSN 10. HLR MAP Cancel Location old SGSNold SGSN PDP Context SGSN Cancel Location ACK HLR
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SGSN (5/7)
11. HLR Insert Subscriber Data SGSN SGSN Routing AreaRA SGSN MM Context Insert Subscriber Data ACK HLR 12. HLR Update Location ACK SGSN
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SGSN (6/7)
13New SGSN Location Update Request new VLR new SGSN 14 VLR GSM HLR VLR old VLR 15New VLR TMSI Location Update Accept new SGSN TMSI new SGSN
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SGSN (7/7)
16SGSN PDP Context MM Context Routing Area Update Accept TMSI 17 Routing Area Update Complete new SGSN N-PDU N-PDU 18New SGSN TMSI Reallocation Complete VLR TMSI
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Section 7.3.2Section 7.3.2GPRSGPRSProcedures of GPRS Attach and Detach
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7-12 GPRS
(old-PTMSI, old SGSN) (old-PTMSI)
(old-PTMSI)
(new P-TMSI)
Um Gb Gn
GPRS signaling plane. GPRS attached MS SGSN GMM layer . MS attach . MS old SGSN , detach. MS new SGSN, , GPRS Attach .Step 1.1. MS GMM layer Attach Request SGSN.Step 1.2. New SGSN GTP Mobility Management Identification_Request(old P-TMSI) old SGSN, MS IMSI.
Case 1: Old SGSN P-TMSI MS IMSI, Identification_Response(IMSI) new SGSN. new SGSN MS (authentication) (ciphering) security procedures.Case 2: , old SGSN MS , error new SGSN. New SGSN Air interface MS IMSI. MS attach, MS new SGSN, new SGSN RA (and possibly the LA) update.
Step 1.3. New SGSN radio priority, New SGSN GMM layer Attach Accept(P-TMSI, VLR TMSI, P-TMSI Signature, Radio Priority SMS) MS.
MS new P-TMSI, MS an acknowledge VLR.
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GPRS (1/2)
SGSN 1. Attach Request SGSN IMSI P-TMSI 2. New SGSN P-TMSI new SGSN Identification Request old SGSN IMSI 3. Old SGSN Identification Response IMSI SGSN
GPRS attach IMSI attachedGPRS AttachGPRS attachIMSI attach
SGSN SGSN 3 SGSN SGSN IMSI
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GPRS (2/2)
4. MM Context 5. RA LA UpdateNew SGSN Update Location Request HLR 6. New SGSN Attach Accept SGSN P-TMSI
7. new SGSN Attach Complete
5 GPRS SGSN SGSNRA LA Update
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MS-Initiated Detach GPRS GPRS detach
Network-Initiated Detach GPRS GPRS detach
HLRHLR-Initiated Detach GPRS HLR SGSN
GPRS detach HLR (HLR-initiated), SGSN (SGSN-initiated) MS (MS-initiated). MS Idle state.
SGSN-initiated detach IP network , GGSN fail/reset, PDP context lost. HLR-initiated detach prepaid service money .
GPRS detach, : IMSI detach: GSM network GPRS detach: GPRS network Combined GPRS/IMSI detach: GSM GPRS network
MS Combined GPRS/IMSI detach, . HLR MS , . SGSN HLR , Steps 2.1 2.6 , . MS SGSN , Steps 2.2 Step 2.5 Detach Accept : Detach Request (MSSGSN) Detach Accept(SGSMMS).
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7-13 GPRS
Um Gb Gn Gr D
Gr: in GSM MAP
in GMM layer in GTP layer
Gs: in BSSAPT layer
in GMM layer
HLR detach:Step 2.1. HLR GSM MAP, Gr , MAP_CANCEL_LOCATION(IMSI, Cancellation Type) SGSN, .Step 2.2. SGSN GMM Detach Request MS. detach type parameter MS attach. detach type parameter :
(1) SGSN-initiated detach, the SGSN MS attach.(2) MS-initiated detach, MS detach type GPRS-detach, IMSI-detach, GPRS IMSI detach.
Step 2.3. SGSN GGSN GTP tunnel management Delete_PDP_Context_Request(TID) Response(TID) MS GGSN PDP context.Step 2.4. MS GPRS/IMSI-attached, SGSN BSSAP+ Gs GPRS_Detach_Indication(IMSI) VLR. VLR MS SGSN , paging, location update , GPRS network .
VLR flag, GPRS paging. SGSN VLR, VLR GPRS .
Step 2.5. MS GMM Detach Accept GPRS network.Step 2.6. MS Step 2.5 detach, SGSN GSM MAP Gr MAP_CANCEL_LOCATION_ack HLR, HLR MM and PDP contexts.
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GPRS (2/2)
HLR GPRS 1. HLRCancel Location SGSN
2. SGSN GPRS Detach Request 3.4. SGSN Delete PDP Context Request GGSN PDP contextGGSNDelete PDP Context Response
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GPRS (2/2)
5. SGSN GPRS Detach Indication VLRSGSN 6. SGSNGPRSDetach Accept 7. SGSN MM context PDP contextCancel Location AckHLR
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Section 7.3.3Section 7.3.3GPRSGPRS PDP Context Procedures
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PDP Context
PDP Context Activation MS-Initiated Network-Initiated
GGSN PDP PDU GGSN PDP PDP Context PDP ContextGGSN PDP Context
PDP Context ModificationPDP Context Deactivation SGSN-initiated MS-initiated GGSN-initiated
: MS, SGSN, GGSN PDP context. PDP context procedure . PDP Context .
PDP Context Activation PDP Context activation, MS PSDN/PDN . SGSN MS GGSN , .PDP Context Activation MS, network party (GGSN ).
PDP Context Modification PDP Context , PDP Context update message flow.
PDP Context DeactivationPDP Context Deactivation SGSN, MS, GGSN .
SGSN GGSN Gn interface GTP tunnel management request/response pair.SGNS MS Um /Gb interfaces GMM request/accept pair.
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7-14 GPRS PDP context
in GMM(APN, QoS...) Gn:in GTP layer
(IP address...)
(IP address, negotiated QoS...)
MS network , PDP context activation .Step 1.1. MS GMM Activate PDP Context Request (NSAPI, TI, PDP Type, PDP Address, Access Point Name, QoS Requested, PDP Configuration Options) SGSN
MS static dynamic PDP addresses. MS , QoS. SGSN QoS ., SGSN MS security functions.
Step 1.2. SGSN GTP tunnel management Gn Create_PDP_Context_Request GGSN.
SGSN GGSN MS PDP context, PDP contexts tunnel/logical link.GGSN external network IP address MS.GGSN SGSN Create_PDP_Context_Response , SGSN activates the PDP context MS GGSN .
Step 1.3. SGSN PDP context GGSN address dynamic PDP address. SGSN negotiated QoS radio priority, GMM layer Activate PDP Context Accept MS.
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GPRS PDP Context (1/3)
1. Activate PDP Context Request SGSN PDP type, PDP address, APN, QoS profile 2. SGSN GGSN
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GPRS PDP Context (2/3)
3. GGSN SGSN GGSN GGSN
GGSN PDP Context IP GGSN IP
GGSN SGSN Create PDP Context Response IP GGSN
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GPRS PDP Context (3/3)
4. SGSN GGSN IP PDP Context SGSN Activate PDP Context Accept PDP Context
Deactivate PDP Context APN
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PDP Context
GGSN SGSN PDP context PDP context GPRS negotiated QoSradio priorityPDP Traffic Flow TemplateTFT 7-15 SGSN PDP context SGSN-Initiated PDP Context Modification Procedure
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7-15 SGSN PDP Context
BSS SGSN GGSN
1. Update PDP Context Request
3. Modify PDP Context Request
2. Update PDP Context Response
4. Modify PDP Context Response
SGSN PDP Context , GGSN MS .Step 1 (GTP tunnel management on Gn interface).
SGSN GGSN Update_PDP_Context_Request Response.
Step 2 (GMM/Um and Gb interfaces).SGSN MS Modify PDP Context Request Accept MS PDP context. MS SGSN QoS, MS (deactivate) PDP context.
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7-16 PDP Context
MS PDP context deactivation , deactivation .
Step 1. MS Deactivate PDP Context Request (TI: Transaction Identifier) SGSN deactivate PDP context.
MS SGSN Security functions . (optional, )
Step 2, 3. SGSN Gn interface GTP Delete PDP Context Request (TID: Tunnel Identifier) GGSN. GGSN PDP context Delete PDP Context Response (TID) SGSN. MS PDP address, GGSN PDP address PDP context activation MSs .Step 4. SGSN Deactivate PDP Context Accept (TI)message MS, PDP context deactivation.
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Section 7.3.4Section 7.3.4GPRSGPRS Billing
GPRS , PDP context activated , . ,. GPRS . GGSN, SGSN , CDR. GPRS .Billing .
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GPRS (1/2)
GPRS SGSN
GGSN
SGSN GGSN Call Detailed RecordCDRCharging Gateway FunctionCGF SGSN GGSN Billing SystemBS
GSM MSCGPRS SGSN GGSN .SGSN MS radio resource usage.GGSN MS network usage.
GPRS network external network . MS GPRS network , GPRS network dynamic address to an MS, home GPRS network.
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GPRS (2/2)
CDR CDR CDR SGSN CDRInter-SGSN
Routing Area Update
GPRS GSN CDR
(activate) PDP context , CDR. PDP context S-CDRs G-CDRs. GSN, GSNs CDRs.CDR :
End-of-Call Accounting Schedule: Time-of-Day Accounting Schedule: Inter-SGSN Routing Area Update: SGSN RA
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7-17 GPRS
GPRS
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GPRS
SGSN GGSN
BSC
BTS
MS 1
Service Application
MSC
PLMN
MSC CGF
GPRS Billing Mediation
Billing System
Billing records
Backbone network
CGF: Charging Gateway Function
CDR: Charging Data Record
Charging gateway Function (CGF), SGSNs/GGSNs CDR .Charging gateway function (CFG) charging data record (CDR) .CDR GPRS Billing Mediation (), billing record, Billing system, .
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SGSN
SGSN PDP GPRS
SGSN : Location information MS home network visited network, cell location . Mobile origination, mobile termination , QoS profile, .SMS MS PDP context .MS GPRS . MS, GPRS activity (e.g., MM context).
Note: SGSN SNDCP level . IP. , .
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GGSN
GGSN SGSN PDP
GGSN :Destination source addresses ( address GPRS operator ).MS external data network (). QoS profile, .MS PDP address .
Note: GGSN GTP level , IP , GPRS .
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(1/2)
GPRSCDRS-CDRG-CDRM-CDRS-SMO-CDR S-SMT-CDRS-CDR SGSN IMSISGSNcharge identifierGGSNAPNAPNPDPPDPSGSN
G-CDR GGSN IMSIGGSNSGSNAPNPDPPDPGGSN
SGSN GGSN Call Detailed Records (CDR).Call Detailed Record (CDR)
S-CDR (SGSN PDP context generated-CDR): SGSN , MS .G-CDR (GGSN generated-CDR): GGSN , MS GGSN .M-CDR (Mobility Management generated-CDR): SGSN , MS .S-SMO-CDR (mobile origination) SGSNIMSISGSN E.164SGSN
S-SMT-CDR (mobile termination) SGSNSGSNS-SMO-CDRS-SMO-CDRSGSNSGSN
M-CDRSGSNIMSISGSNRALA
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(2/2)
M-CDR SGSN IMSISGSN
RALA S-SMO-CDR SGSN IMSISGSN E.164SGSN
S-SMT-CDR SGSN SGSN S-SMO-CDRSGSNSGSN
S-CDR (SGSN PDP context generated-CDR) :Mobile Originating (MO) data volume: Mobile Terminating (MT) data volume: Location Information: SMS MO: SGSN Mobile originated SMS recordSMS MT: SGSN Mobile terminated SMS recordAssociated QoS: QoS Record Duration: record SGSN
G-CDR (GGSN generated-CDR) : QoS Record Duration: record GGSN
GGSNPDP ContextSGSN. GGSNSGSN/GGSNCDR, PDP Context GGSNGGSNCGFBSGGSN
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GPRS
: GSMGPRS PDP context
GSM GPRS CDR GPRSCGFSGSNs/GGSNs
(packet-switched) circuit-switched , :1., .2. GSM GPRS CDR .
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Section 7.4Section 7.4Summary
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Summary
GPRS3Gbursty and bulkyradio resource on demandalways onvolume-dependent charging3GB3Gbeyond 3G
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Homework
1 (1)-1(10),1,3,5,7,9
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APN (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.
GPRS (GGSN, SGNS ) addressing , operator , (domain nameIP address) , APN GPRS , MS . , APN , GPRS service, name GPRS GGSNAPN Label DNS GPRS APN, .
Internet domain name a page on a specific server, APN service, , , GGSN. GGSN , ex: one GGSN for emone, one GGSN for WAP. ( 5 GGSN for WAP, load balancing, DNS GGSN lists ). Internet , DNS domain name IP address, GPRS network DNS server, APN GGSN IP address.
HLR MS APN, HLR MS APN.HLR APN* default APN, user APN.
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Access a GPRS Service with an APN
Mobile 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.
GPRS service : service, MS request SGSN.SGSN HLR , service user.SGSN local GPRS DNS server APN GGSN IP address. DNS a list of GGSNs IP addresses. local DNS APN IP address:Case 1: user home network, request .Case 2: user foreign network, SGSN MS home network DNS . GGSN IP address, SGSN GGSN tunnel by GTP. GGSN IP MS, MS.
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IP Address Allocation
Fixed 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.
MS external network PDP context, MS IP address. GPRS MS IP address :Fixed addressing:
MS IP address, IP address HLR . MS PDP context APN, HLR IP address SGSN, MS. MS network IP address. fixed IP address, ID. fixed IP address IP , ICANN .
Dynamic addressing: MS PDP context , GGSN IP address MS. PDP context, GGSN IP address.IP address. IP address,
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Mechanism to Get IP Address
From a local address pool on the GGSNVia DHCPVia RADIUS from an external RADIUS serverFrom the customer network via an L2TP tunnel from the GGSN
GGSN IP address: From a local address pool on the GGSN
PSTN dialup server. GGSN IP address pool, MS IP, GGSN pool IP MS., APN address pool. APN IP address space, private network IP range. operator IP, .
Via DHCPDHCP server operator (GPRS internally) customer network. So, DHCH server GGSN . DHCP server GGSN LAN .GGSN DHCP server () IP address. DHCP server fixed IP address, MS IP address.
Via RADIUS form an external RADIUS server RADIUS server customer network.GGSN RADIUS server user terminal, fixed IP address.
From the customer network via an L2TP tunnel from the GGSNL2TP layer 2 tunneling protocol. IP user traffic IP network . PSTN dial-up to a Remote Access Server. GPRS , L2TP GGSN customer network router . customers router , IP address. User network . customer security, (operator) . GGSN customers network RADIUS server IP.
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