huawei gprs umts ps fundamental

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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

GPRS&UMTS

PS Fundamental

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Page2Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

Foreword

l GPRS&UMTS PS fundamental is the basic part of the

whole system and the later products learning. This slide will

help us to understand the GPRS system networking and

some important procedure.

http://www.pdffactory.com/http://www.pdffactory.com/


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References

l 3GPP protocol 23060





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Objectives

l Upon completion of this course, you will be able to:

p Describe the GPRS networking structure

p Describe the GPRS mobility management procedure

p Describe the GPRS session management procedure



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Contents

1. GPRS&UMTS Network Structure

2. Mobility Management

3. Radio Resource Management

4. Session Management



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GPRS&UMTS Network Structure

l What is GPRS?

p General Packet Radio Service

l What is the function of GPRS?

p In order to provide the data service out the scope of the fixed network

l GPRS network classification

p GSM GPRS

p UMTS GPRS

l GPRS network background

p GSM GPRS network reuse the existed GSM network

p UMTS GPRS network just change the RAN side



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FR/IP

EIREIRHLRHLRSMS-GMSCSMS-IWMSC

SMS-GMSC

SMS-IWMSCMSC/VLRMSC/VLR

BSSBSS

UTRANUTRAN

SGSNSGSN

SGSNSGSN

GGSNGGSN

BGBG

CGCG

TETEPDN

SS7

ATM

DDN

ISDN

Ethernet.etc

GPRSBackbone

Gs Gd Gr Gf Gc

Gb

Iu

Um

Um

Gp

Gi

Gn

Gn

Ga

SCPSCP GMLCGMLC

Ge Lg

Ga

ATM/IP



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l Some Abbreviation

p GPRS: General Packet Radio Service

p BSS: Base Station Subsystem

p UTRAN: UMTS Terrestrial Radio Access Network

p SGSN: Service GPRS Support Node

p GGSN: Gateway GPRS Support Node

p CG: Charging Gateway

p BG: Border Gateway

p PDN: Packet Data Network



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l Abbreviations:

p MSC/VLR: Mobile Switch Center/Visitor Location Register

p SMS-GMSC: Gateway MSC For Short Message Service

p SMS-IWMSC: Short Message Service Interworking MSC

p SCP: Service Control Point

p GMLC: Gateway Mobile Location Center

p HLR: Home Location Register

p EIR: Equipment Identity Register



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Functions of SGSN

l Important Entity Function: SGSNp Mobility management

n The MM functions are used to keep track of the current location of

an MS within the PLMN or within another PLMN.

p Session management

n SM function manages the PDP context of MS.

p Routing and transfer

n SGSN performs routing and forwarding of service data between

MS and GGSN.

p Charging

n SGSN can generate, store, convert and send CDRs.

p Lawful Interception

p NTP



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Functions of GGSN

l Important Entity Function : GGSN

p Session management

n SM function manages the PDP context of MS.

p Routing and transfer

n

GGSN performs routing and forwarding of service data between MS andinternet.

p Charging

n GGSN can generate, store, convert and send CDRs.

p Dynamic IP allocation

p Service management

n Manage APN



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Functions of CG

l Important Entity Function: CG

p Real-time collection of GPRS CDRs

p Temporary storage and buffering of GPRS CDRs

p Pre-processing of GPRS CDRs

p Sending GPRS CDRs to the billing center



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Functions of DNS

l Important Entity

Function: DNS

SGSN GGSN(A)

MS

BSS

GPRS backboneGPRS backboneGPRS backbone

ISP AISP AISP A

ISP BISP BISP B

Internet/

IntranetGGSN(B)DNS

p Resolve the APN to a GGSN IP in the PDP active procedure

p Resolve the RAI to a SGSN IP in the inter-SGSN RAU procedure

p Resolve the RNCID to a SGSN IP in the relocation procedure(UMTS)



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Functions of HLR

l Important Entity Function: HLR

p Saving and updating GPRS subscriber subscription data

p User authentication

p Providing location information and processing needed in

mobility management and routing, for example

n Saving and updating user service SGSN number and address

n GPRS user location deletion indication

n Whether MS is reachable



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Functions of BG

l BGthe border gateway between two PLMN, It provides, apart

from the security function, the routing function between SGSNs

and GGSNs in different GPRS/UMTS networks.

l BG supports the following necessary protocols for inter-networking

of the different operators;

p Security protocolrecommend to use IPSEC and firewall;

p Routing protocol recommend to use BGP

l Base on common router;

Gp

PLMN A

GSN RRBG

RR

BGGSN

PLMN B



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Functions of AAA server

l AAA Server is used to perform authentication, authorization

and accounting functions.

l In Non-transparent access mode, the GGSN will

communicate with remote AAA Server to check the validity

of MS/UE by using RAIDUS (Remote Authentication Dial In

User Service) protocol.



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SMS-GMSC and SMS- IWMSC

l SMS-GMSC and SMS-IWMSC: are the part of SMSC, and

used to handle the MAP protocol.

l The Short message can be sent via CS domain or PS

domain.

l The operator can decide to use CS or PS to send the short

message to MS.

MS SGSNSMS-IWMSC

SMS-GMSC

GdSMS



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User Terminal: MS (2G)

l A GSM/GPRS Mobile Station can operate inone of three modes of operation:

p Class A:

n operates GPRS and other GSM services

simultaneously

p Class B:n monitors control channels for GSM GPRS

and other GSM services simultaneously, but

can only operate one set of services at one

time

p Class C:

n exclusively operates GPRS services



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User Terminal: UE (3G)

l A UMTS user equipment can operate in one ofthree modes of operation:

p PS/CS mode:

n operates PS and CS services

simultaneously

p PS mode:

n exclusively operates PS services

p CS mode:

n exclusively operates CS services

In order to read more easily, 2G MS and 3G UE areall named as MS in this document.



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Summary

l GPRS network provides data service to the mobile

subscribers.

l GPRS network is composed of SGSN, GGSN and CG. BG

and DNS provide special function during the data service.



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Objectives

l GPRS&UMTS Network Structure

l Mobility Management

l Radio Resource Management

l Session Management



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Contents


2.1 Basic concepts

2.2 Attach and Detach

2.3 Security Function

2.4 Location Management

2.5 Service Request (UMTS only)



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GMM (GPRS Mobility Management)

l Function of the Mobility Management

p keep track of the current location of an MS within the PLMN or

within another PLMN

p Subscription data management

p MS states management



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GMM (GPRS Mobility Management)

l GMM main procedures

p Attach procedure

p RAU and periodic procedure

p Detach procedure

l GMM other procedures

p P-TMSI reallocation procedure

p Authentication procedure

p Identification procedure

p Subscriber management procedure



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GMM States

PDU transmission

Implicit Detach

or

Cancel Location

GPRS Attach

READY timer expiry

or

Force to STANDBY

GPRS Detach GPRS Attach

PDU reception

GPRS Detach

or

Cancel Location

MM State Model of MS MM State Model of SGSN

IDLE

READY

STANDBY

IDLE

READY

STANDBY

READY timer expiry

or

Force to STANDBY

or

Abnormal RLC condition



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PMM (Packet Mobility Management)

l The function of PMM is similar to GMM.

l PMM other procedures

pP-TMSI reallocation

pAuthentication

pIdentification

pSubscriber management

l PMM main procedures

pAttach

pRAU and periodic RAU

pDetach

pService request

pSRNS relocation



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PMM States

PMM-DETACHED

PS Attach

PS SignallingConnection Release

PS SignallingConnection Establish

PS D etach

PMM-CONNECTEDPMM-IDLE

Detach,PS Attach Reject,RAU Reject

PMM-DETACHED

PS Detach

PMM-CONNECTED

Serving RNC

relocation

3G-SGSN MM StatesMS MM States

SM-ACTIVE orINACTIVE




Detach,PS Attach Reject,RAU RejectPS Attach

PS SignallingConnection Establish

PS SignallingConnection Release

PMM-IDLE



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Mobility Management Timer Functions

l READY Timer Function (GSM only)

p The READY timer controls the time an MS remains in READY

state in the MS and the SGSN. When the READY timer expires,

the MS and SGSN MM contexts shall return to STANDBY state.

l Periodic RA Update Timer Function

p Upon expiry of the periodic RA update timer, the MS shall start a

periodic routeing area update procedure.

l Mobile Reachable Timer Function

p If the mobile reachable timer expires, the SGSN shall clear PPF.

p After expiry of the mobile reachable timer the SGSN may perform

an implicit detach.



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Contents


2.1 Basic concepts







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Attach Procedure

l Function

p An MS/UE shall perform a GPRS Attach to the SGSN in order

to obtain access to the GPRS services.

p If the MS/UE is connected via a GSM radio, it shall perform a

GSM GPRS Attach procedure.

p If the MS/UE is connected via a UMTS radio access network, it

shall perform a UMTS GPRS Attach procedure



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Attach Procedure

(IMSI or PTMSI+RAI) (PTMSI)

(IMSI)

(Identity Type = IMSI)

(IMSI)



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Attach Procedure



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Attach Procedure

l Results after any attach procedure:

p SGSN get subscriber data from HLR

p HLR recorded the MSs serving SGSN number

p SGSN and MS create MM context for the MS

l MS can request Session Management services



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MM Context

X1)Currently used Iu mode ciphering key.CK

XXSelected ciphering algorithm (GEA).Ciphering algorithm

2)XCiphering key sequence number of Kc.CKSN

2)XCurrently used A/Gb mode ciphering key.Kc

XXAuthentication and ciphering parameters (authentication triplets or quintets).Authentication Vectors

XXThe IP address of the new SGSN where buffered and not sent N-PDUs should be

forwarded to.

New SGSN Address

XXThe VLR number of the MSC/VLR currently serving this MS.VLR Number

XTime elapsed since the last SAC was received at the 3G-SGSN.Service Area Code Age

XLast known SAC when initial UE message was received or Location Reporting

procedure was executed.

Service Area Code

XTime elapsed since the last LLC PDU was received from the MS at the SGSN.Cell Identity AgeXCurrent cell in READY state, last known cell in STANDBY or IDLE state.Cell Identity

XXCurrent routeing area.Routeing Area

XXThe basic MSISDN of the MS.MSISDN

XXInternational Mobile Equipment IdentityIMEI

XXA signature used for identification checking purposes.P-TMSI Signature

XXPacket Temporary Mobile Subscriber Identity.P-TMSI

XXMobility management state, IDLE, STANDBY, READY, PMM-DETACHED, PMM-IDLE,

or PMM-CONNECTED.

MM State

XXIMSI is the main reference key.IMSI

Iu modeA/Gb

mode

DescriptionField



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MM Context

XThe RLC/MAC radio priority level for uplink SMS transmission.Radio Priority SMS

XXIndicates that the status of the operator determined barring for packet oriented

services.

ODB for PS parameters

XXOptional GPRS CAMEL subscription information, see 3GPP TS 23.016GPRS-CSI

XXIndicates if HLR or VLR is performing database recovery.Recovery

XXSMS-related parameters, e.g. operator-determined barring.SMS Parameters

XXThe charging characteristics for the MS, e.g. normal, prepaid, flat-rate, and/or

hot billing subscription.

Subscribed Charging

Characteristics

XXIndicates whether paging for PS and CS services can be initiated.PPF

XXIndicates whether activity from the MS shall be reported to the MSC/VLR.NGAF

XXIndicates whether activity from the MS shall be reported to the HLR.MNRG

XXDiscontinuous reception parameters.DRX Parameters

XXMS network capabilities.MS Network Capability

XMS radio access capabilities.MS Radio Access Capability

X1)Key Set Identifier.KSI

X1)Currently used Iu mode integrity key.IK

l The information marked with a "1)" may be maintained if authentication is performed by the UMTSauthentication procedure.

l The information marked with a "2)" may be maintained if authentication is performed by the GSM

authentication procedure.



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Detach Procedure

l Functionp The GPRS Detach procedure allows an MS to inform the network that

it does not want to access the SGSN-based services any longer

p The GPRS Detach procedure allows the network to inform an MS that

it does not have access to the SGSN-based services any more

l The following three entity can initiate the detach procedure

p MS

p SGSN

p HLR



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Detach Procedure

l Results after any Detach procedure:p The SGSN shall not service the detached MS, unless reattach

p The MS is in idle or PMM-DETACHED state

l The MS is detached either explicitly or implicitly:

p Explicit detach: The network or the MS explicitly requests detach

p Implicit detach: The network detaches the MS, without notifying the

MS, a configuration-dependent time after the mobile reachable timer

expired, or after an irrecoverable radio error causes disconnection of

the logical link.



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Detach Types

l

The different types of detach are:p IMSI detach;

p GPRS detach;

p combined GPRS / IMSI detach (MS-initiated only).

l

The MS can make an IMSI detach in one of two ways depending onwhether it is GPRS-attached or not:

p A GPRS-attached MS sends a Detach Request message to the SGSN,

indicating an IMSI detach. This can be made in combination with GPRS detach.

p An MS that is not GPRS-attached makes the IMSI detach as already defined in

A/Gb mode or UMTS.



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Detach Procedure (MS Initiated)

3. IMSI Detach Indication

2. Delete PDP Context Response

1. Detach Request

2. Delete PDP Context Request

5. Detach Accept

MS BSS/UTRAN GGSNSGSN MSC/VLR

4. GPRS Detach Indication

6. PS Signalling Connection Release

C2

C1



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Detach Type IE of Detach Request

In the network to MS direction thePower offbit shall be spare and set to

zero.

power switched off1

normal detach0

4

Bit

In the MS to network direction:

Power off (octet 1)

Type of

detach

Power

off

Detach

type

IEI

12345678

All other values are interpreted as re-attach not requiredby this version of theprotocol.

IMSI detach (after VLR failure)110

re-attach not required010

re-attach required100

123

Bits

In the network to MS direction:

All other values are interpreted as

Combined GPRS/IMSI detach by thisversion of the protocol.

Combined GPRS/IMSI detach110

IMSI detach010

GPRS detach100

123

Bits

In the MS to network direction:

Type of detach (octet 1)



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Detach Procedure (SGSN Initiated)


1. Detach Request2. Delete PDP Context Request

4. Detach Accept

MS BSS/UTRAN GGSNSGSN MSC/VLR



C1

C2



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Detach Procedure (HLR Initiated)

HLRMS BSS/UTRAN GGSNSGSN MSC/VLR


1. Cancel Location


2. Detach Request

6. Cancel Location Ack


5. Detach Accept


C2

C1



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Purge Function

l

Functionp The Purge function allows an SGSN to inform the HLR that it has deleted the

MM and PDP contexts of a detached MS

l After the MS detach from the network:

p The SGSN may delete the MM/PDP context immediately

p the SGSN may keep the MM/PDP context for some time of the detached MS

l Purge Timer Function

p Allows the SGSN to inform the HLR that it has deleted the MM and PDP

contexts of a detached MS.

p The purge timer is set longer than the mobile reachable timer



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Purge Function

1. Purge MS

2. Purge MS Ack

SGSN HLR



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Contents


2.1 Basic concepts







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Authentication Function

l Function

p Permit the network to check whether the identity provided by

the mobile station is acceptable or not;

p Provide parameters enabling the mobile station to calculate a

new ciphering key ;UMTS and GSM

p Provide parameters enabling the mobile station to calculate a

new UMTS integrity key;UMTS only

p Permit the mobile station to authenticate the network.UMTS

only



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l

Authentication types:p GSM Authentication

n Using triplet: RAND, SRES, Kc

n Using GPRS Encryption Algorithm (GEA)

p UMTS Authentication

n Using quintet: RAND, XRES, AUTN, CK, IK

AUTN: for UE authenticate network

IK: for data integrity function

n Using UMTS Encryption Algorithm (UEA)

l These procedures are used independent of the GSM or UTRAN RANs,

i.e. each procedure may be executed in A/Gb mode or in Iu mode.



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1a. Send Authentication Info

2a. Authentication and Ciphering Request

1b . Send Authentication Info ack

2b. Authentication and Ciphering Response

MS BSS/UTRAN HLR/AucSGSN



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Authentication Function(3G)MS VLR/SGSN HE/HLR

Generate authentication

vectors AV(1..n)

Store authentication vectors

Select authentication vector AV(i)

Au the ntic ation da ta req uest

Au thenticat ion da ta res pon se

AV(1..n)

User authentication requestRAND(i) || AUTN(i)

User authentication responseRES(i)

Compare RES(i) and XRES(i)

Verify AUTN(i)

Compute RES(i)

C om pute CK (i) and IK (i) Select CK (i) and IK (i)

Authentication and

key establishment

Distribution ofauthenticationvectors from HE

to SN



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Scope and Start of Ciphering

l In A/Gb mode, the scope of ciphering is from the ciphering function in the

SGSN to the ciphering function in the MS.

l In Iu mode, the scope of ciphering is from the ciphering function in the

UTRAN to the ciphering function in the MS.

l In A/Gb mode, the MS starts ciphering after sending the Authentication

and Ciphering Response message.

l In Iu mode, the start of ciphering is controlled by the security modeprocedure after authentication procedure.

MS BSS/UTRAN SGSN

Scope of GSM GPRS ciphering

Scope of UMTS ciphering



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Identity Check

l Function

p Get IMSI from MS

p Check the IMEI

1. Identity Response

2. Check IMEI

1. Identity Request

2. Check IMEI Ack

MS BSS/UTRAN EIR SGSN



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P-TMSI Reallocation

l

Functionp The SGSN may reallocate the P-TMSI at any time

p The reallocation procedure can be performed by the P-TMSI

Reallocation procedure

p The P-TMSI can be included in the Attach or Routeing Area Update

procedures.

2. P-TMSI Reallocation Complete

1. P-TMSI Reallocation Command

MS BSS/UTRAN SGSN



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Contents


2.1 Basic concepts







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Location Management

l Function

p A mechanisms for cell and PLMN selection;

p A mechanism for the network to know the Routeing Area for MSs in

STANDBY, PMM-IDLE, READY, and PMM

-CONNECTED states;

p A mechanism for the 2G-SGSN to know the cell identity for MSs in

READY state;


Layered Location Management Mode (2G)


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SGSN

HLR

BSS

MS

SGSN number

ready state: cell number

Standby state: RAI




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SGSN

HLR

RNC

MS

SGSN number

PMM-connect state: RNCID,RAI,SAI

PMM-idle: RAI


N t k A hit t


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Network Architecture

l Routeing area update procedure

p SGSN can manage the MS

location information via RAU

procedure in RAI level

l Relocation procedure (UMTS

only)

p Move the Iu interface to the

other RNC

l Handover procedure

p Move the radio link to the other

BTS/NodeB

old SGSN

RNC2RNC1

MS

GGSN

Iu

new SGSN

RNC4 RNC3

IU

HLR/AUC

Gn/Gp Gn/Gp

PDN

Gi

Gr GrIU

Iu

Gn

RA1 RA2 RA3

RA4 RA5

RA6 RA7 RA9

RA9 RA10

Iur


R t i A U d t P d


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Routeing Area Update Procedure

l RAU procedure will happen in the following two case:p MS entered a new Route Area

p Periodic RAU ( after periodic timer expires)

l In the viewpoint of SGSN:

p intra-SGSN RAU

p Inter-SGSN RAU


R t i A U d t P d


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Routeing Area Update Procedure

MS

RAI 2 RAI 4

SGSN SGSN

RAI 1 RAI 3

cell

Intra SGSN-RAU

Inter SGSN -RAU

Gn


Inter SGSN RAU Procedure (2G)


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Inter-SGSN RAU Procedure (2G)




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Contents


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Contents

2. Mobility Management2.1 Basic concepts






Service Request Procedure


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Service Request Procedure

l The Service Request procedure is used by a 3G-MS in PMM-IDLE

state to request the establishment of a secure connection to a

3G-SGSN.

l The MS in PMM-IDLE state initiates this procedure in order to

send uplink signalling messages (e.g. Activate PDP Context

Request), user data, or as paging response, or after the MS has

regained radio coverage.

l This procedure is also used by an MS in PMM-CONNECTED

state to request resource reservation for active PDP contexts.


MS Initiated


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SGSNMS

2. Service Request

3. Security Functions

RNC

1. RRC Connection Request

8. Uplink PDU

1. RRC Connection Setup

4. Radio Access Bearer AssignmentRequest

6. Radio Access Bearer AssignmentResponse

5. Radio Bearer Setup

6. Radio Bearer SetupComplete

HLR GGSN

7. SGSN-Initiated PDP Context Modification

4. Service Accept

MS Initiated


Network Initiated


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7. SGSN-Initiated PDP Context Modification Procedure

8. Downlink PDU

SGSNMS


RNC

3. RRC Connection Request

1. Downlink PDU

3. RRC Connection Setup

6. Radio Access Bearer Ass ignmentRequest

6. Radio Access Bearer Ass ignmentResponse

6. Radio Bearer Setup

6. Radio Bearer SetupComplete

2. Paging

2. Paging

4. Service Request

HLR GGSN

Network Initiated


Service Type IE of Service Request Msg


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Service Type IE of Service Request Msg.

l

MS initiatedp Service type= signalling.

p Service type= data.

l Network initiated

p Service type= paging response


Summary


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Summary

l

Attach, location management, security function and detachprocedures are the main procedures in PS core network.

l SRNS relocation procedure and Service request procedure

are newly added in UMTS PS core network.


Contents


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Contents

1. GPRS&UMTS Network Structure2. Mobility Management




Paging Summary


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Paging Summary

l The MM state in SGSN and MS before paging:

p PMM-IDLE

p STANDBY mode

l Change MM state in MS to PMM-Connected or Ready after

successful paging.

l Identification of MS in Paging message:

p P-TMSI is used to identify the MS

p If P-TMSI is invalid or MS not respond ,then use IMSI


Paging for GPRS (2G)


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l

Functionp An MS in STANDBY state is paged by the SGSN before a

downlink transfer to that MS

p Paging move the MS state from STANDBY to READY.

p Any uplink data from MS is a valid response to paging




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g g ( )

5. Any LLC Frame

4. Any LLC Frame

3. GPRS Paging Request

2. Paging Request

1. PDP PDU

MS BSS SGSN

STANDBY

READY

(IMSI, P-TMSI,

Area, ChannelNeeded, QoS,

DRX

Parameters)

(Receive Ready or

Information frame)


Paging Initiated by CN (3G)


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g g y ( )

l PS Paging Initiated by 3G-SGSN without RRC Connection

for CS

p A CN node requests paging only for MSs in PMM-IDLE state

p The RNS controls whether the MS has an established RRC

connection or not

p MS has no RRC connection

p Paging Type 1 is transferred on the Paging channel




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g g y ( )

4. Service Request

4. Service Request

3. Paging Type12. Paging

MS RNS MSC/VLR

3G-SGSN

1. PDP PDU or

Downlink signalingPMM IDLE

PMM

CONNECTED

(PCH paging)(IMSI,

P-TMSI, Area,

CN Domain

Indicator, DRX

parameters)

lPS Paging Initiated by 3G-SGSN without RRC Connection for CS




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g g y ( )

l PS Paging Initiated by 3G-SGSN with RRC Connection for CS

p A CN node requests paging only for MSs in PMM-IDLE state

p The RNS controls whether the MS has an established RRC

connection or not

p In this case, MS has an established RRC connection for CSservice

p Paging Type 2 is base on the establish RRC connection




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lPS Paging Initiated by 3G-SGSN with RRC Connection for CS

4. Service Request

4. Service Request

3. Paging Type22. Paging

MS RNS MSC/VLR

3G-SGSN

Connection Established

1.PDP PDU orDownlink signalling

(RRC paging)

(IMSI,

P-TMSI, Area,

CN Domain

Indicator, DRXparameters)

PMM IDLE

PMM

CONNECTED

g g y ( )


CS Paging (GSM only)


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l When an MS is both IMSI and GPRS-attached in a network that operates in

mode I, the MSC/VLR executes paging for circuit-switched services via the SGSN.

If the MS is in STANDBY state, it is paged in the routeing area and in the null

routeing area (see clause "Routeing Area Identity of TS23060). If the MS is in

READY state, it is paged in the cell. The SGSN converts the MSC paging message

into an SGSN paging message.

4. SABM (Paging Response)

5. SCCP Connection Request (Paging Response)

1. Page

3. Paging Request

2. Paging Request

MS BSS SGSN MSC/VLR


CS Paging (UMTS only)


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l When an MS is both IMSI- and GPRS-attached in a network

that operates in mode I, the MSC/VLR executes paging for

circuit-switched services via the SGSN.

l In the MSC, a paging timer supervises the paging procedure.

4. RRC Initial Direct Transfer (Paging Response)

5. RANAP Initial UE (Paging Response)

1. Page

3. Paging Request

2. Paging

MS RNS 3G-SGSN MSC/VLR


Summary


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l In UMTS, Paging type 1 for UE without RRC connection

with RNC, Paging type 2 for UE with RRC connection with

RNC.

l CS paging can be executed via PS.


Contents


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1. GPRS&UMTS Network Structure





Contents


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4.1 Basic concepts

4.2 PDP Context Activation Procedure

4.3 PDP Context Modification Procedure

4.4 PDP Context Deactivation Procedure


Session Management


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l Function

p Establish and monitor a packet tunnel from MS to GGSN, and allocate

system resource for the packet service.

l Important Procedure

p PDP Context Activation

p PDP Context Modification

p PDP Context Deactivation


PDP Context


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l PDP Context: Packet Data Protocol context

p PDP context contains all the information needed to transfer

user data between MS and GGSN.

p

The context includes parameters such as RA, QoS (Quality ofService), Charging ID etc.

p PDP context exists in MS, SGSN, GGSN.


PDP Context


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XXIndex of the PDP context.PDP Context Identifier

XXThe quality of service profile subscribed.QoS Profile Subscribed

XXSpecifies whether the MS is allowed to use the APN inthe domain of the HPLMN only, or additionally the

APN in the domain of the VPLMN.

VPLMN AddressAllowed

XXThe IP address of the GGSN currently used.GGSN Address in Use

XTunnel Endpoint Identifier for the Iu interface.TEID for Iu

XXTunnel Endpoint Identifier for the Gn and Gp interfaces.TEID for Gn/Gp

XXTransaction Identifier.TI

XXNetwork layer Service Access Point Identifier.NSAPI

XXThe APN currently used. This APN shall be composedof the APNNetwork Identifier and the APN Operator

Identifier.

APN in Use

XXThe APN received from the HLR.APN Subscribed

XXPDP address, e.g. an IP address.PDP Address

XXPDP type, e.g. PPP or IP.PDP Type

XXPacket data protocol state, INACTIVE or ACTIVE.PDP State

Iu

mode

A/Gb

mode

DescriptionField

Each MM context contains zero or more of the following PDP contexts:


PDP Context


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XThe IP address of the RNC currently used.RNC Address in Use

XXThe charging characteristics of this PDP context, e.g.normal, prepaid, flat-rate, and/or hot billing.

PDP Context ChargingCharacteristics

XXCharging identifier, identifies charging records generatedby SGSN and GGSN.

Charging Id

XSequence number of the next uplink in-sequencePDCP-PDU expected from the MS.

PDCP-SNU

XSequence number of the next downlink in-sequencePDCP-PDU to be sent to the MS.

PDCP-SND

XXGTP-U sequence number of the next uplink N-PDU to besent to the GGSN.

GTP-SNU

XXGTP-U sequence number of the next downlink N

-PDU tobe sent to the MS.GTP-SND

XSNDCP sequence number of the next uplink N-PDUexpected from the MS.

Receive N-PDU Number

XSNDCP sequence number of the next downlink N-PDUto be sent to the MS.

Send N-PDU Number

XThe aggregate BSS quality of service profile negotiatedfor the packet flow that this PDP context belongs to.

Aggregate BSS QoSProfile Negotiated

XPacket flow identifier.Packet Flow Id

XThe RLC/MAC radio priority level for uplink user datatransmission.

Radio Priority

XXThe quality of service profile negotiated.QoS Profile Negotiated

XXThe quality of service profile requested.QoS Profile Requested


MM Context and PDP Context


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HLR

SGSNBSC

or RNC

MS GGSN

GnGb/ IuUu

PDP context #n

.

.

PDP context #1

MM context

PDP context #n

.

.

PDP context #1

MM context

PDP context #n

.

.

.

PDP context #1


PDP State


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Deactivate PDP Context

or

MM state change to IDLEor PMM-DETACHED

Activate PDP

Context

INACTIVE

ACTIVE

l PDP state

p inactivecannottransmit data

p

active

can transmitdata


PDP Type and PDP Address


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l PDP Type

p IPV4

p IPV6

p PPP

l PDP Address

p Static IP

n Public IP

n Allocate by the operator

p Dynamic IP

n Private IP

n Allocate by GGSN, DHCP or Radius


QoS


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l QoS: quality of service

p It is a group of parameters that can define the network ability,

such as the bit rate for downlink or uplink data transmission

and the reliability class and so on

p It is end to end concept


APN


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l APN structure: APN-NI+APN-OI

huawei.com.cn.mnc.mcc.gprs

APN

Network ID

APN

Operator ID

Operator ID : fixed extension, must end with .gprs

Network ID shall not end with .gprs


APNGGSN1

APN1


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MS SGSN

GGSN1

GGSN2

GGSN3

DNS

APN1

APN2

APN3

APN1=GGSN1 IP1

APN2=GGSN2 IP2APN3=GGSN3 IP3

APN

APN GGSN IP

APN1

APN2

APN3

IP1


G l

APN


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SGSN

MS

SGSN

MS

internet

GGSN GGSN

Roaming

APN:CMNET

GuangDong province

l General

APN


l Local APN

APN


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SGSN

MS

SGSN

MS

GGSN GGSN

Roaming

APN:test.xy

VPN tunnel

Province 1 Province 2


APN


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DNS

BTS

/NodeB

SGSN

MS

DNS

BSC

/RNC

GGSN (B)BackboneBackbone

DNS

ISP BISP B

ISP AISP A

Corp.

Network

Corp.

Network

GGSN (A)

APNAPN--NI/NI/

Or APNOr APN--NI+APNNI+APN--OIOI

APNAPN--NI+APNNI+APN--OIOIGGSN IP addressGGSN IP address

APNAPN--NINI


Contents


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4.1 Basic concepts





Activation Procedure


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l

PDP context activation procedurep To establish a PDP context between the MS and the

SGSN, the GGSN

l

Activation procedure types:p PDP context activation procedure

p Secondary PDP Context Activation Procedure

p Network-Requested PDP Context Activation

Procedure


PDP Context Activation Procedure (2G)


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2G-GGSN

5. Activate PDP Context Accept

3. Create PDP Context Response

3. Create PDP Context Request

1. Activate PDP Context Request

2G-SGSNBSS


MS

4. BSS Packet Flow Context Procedures


PDP Context Activation Procedure (3G)


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(PDP Type, PDP Address, Access Point Name,

QoS Requested)

Charging ID allocation

IP address

3G-GGSN

7. Activate PDP Context Accept

3. Create PDP Context Response

2. Create PDP Context Request

1. Activate PDP Context Request

3G-SGSNUTRANMS

4. Radio Access Bearer Setup

Qos

6. Update PDP Context Response

5. Update PDP Context Request


Handling in MS


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l MS start and send Active PDP context request to SGSN

p Provide QoS parameter

p Provide a APN-NI

p Provide a static IP or null

l Receive ACCEPT from SGSN

p If the QoS not accept by MS, then starts delete PDP context

procedure.


Handling in SGSN

l Check subscriber data


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l Check subscriber data

l APN selectionp According to TS 23.060

p default APN, APN provide from MS and the APN subscribed in HLR

p APN-NI.APN-OI

l Interrogate DNSp Hostfile/Cache/DNS server

l

QoS negotiationp QoS provided from MS, default QoS ,QoS subscribed in HLR

l Send message Create PDP context request to GGSN

l RAB assignment (UMTS only)

l Send message Active PDP context accept to MSp Dynamic IP address

p QoS


Handling in GGSN

Ch k th APN id d b SGSN


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l Check the APN provided by SGSN

l QoS negotiation

l Allocate a dynamic IP to the MS

l Allocate a charging ID for the PDP context

l Return a CREATE PDP CONTEXT ACCEPT

message to SGSNp Dynamic IP

p QoS

p Charging ID

p Other information

l

Update PDP context


Handling in RNC


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l RAB assignment

MS SGSN GGSN

RNCRAB assignment

(Final negotiated

Qos)

Allocate Iu interface resourceAllocate radio resource


Network-Requested PDP Context

Activation Procedure


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MS SGSN GGSN

3. PDU Notification Request

HLR

1. PDP PDU

2. Send Routeing Info for GPRS

2. Send Routeing Info for GPRS Ack

4. Request PDP Context Activation

5. PDP Context Activation procedure

3. PDU Notification Response


Contents

4 S i M t


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4.1 Basic concepts





Modification Procedures

l Modification procedures modify parameters that were negotiated


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l Modification procedures modify parameters that were negotiated

during an activation procedure for one or several PDP contexts.

l An MS, a GGSN, an SGSN, or an RNC can request a modification

procedure.

l The following parameters can be modified:

p QoS Negotiated;

p Radio Priority;

p Packet Flow Id;

p PDP Address (in case of the GGSN-initiated modification procedure);

p TFT (in case of MS-initiated modification procedure).


SGSN-Initiated Modification

Procedure


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GGSN



SGSNUTRANMS

3. Modify PDP Context Request

4. Modify PDP Context Accept

5. Radio Access Bearer Modification

C1

6. Invoke Trace


GGSN-Initiated Modification Procedure


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GGSN


1. Update PDP Context RequestSGSNUTRANMS




C1


MS-Initiated Modification Procedure


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GGSN



SGSNUTRANMS




C1


l RNC modify RAB may cause SGSN modify PDP context

RNC-initiated RAB Modification Procedure


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l RNC modify RAB may cause SGSN modify PDP context.

1. RAB Modify Request

RNC SGSN

2. SGSN initiated PDP Context Modification Procedure

MS GGSN


Contents

4 Session Management


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4.1 Basic concepts





MS Initiated Deactivation Procedure

l For GPRS


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l For GPRS

2G-GGSN

4. Deactivate PDP Context Accept



1. Deactivate PDP Context Request

2G-SGSNMS


C1


MS Initiated Deactivation Procedure

l For UMTS


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l For UMTS

3G-GGSN



3G-SGSNUTRANMS



5. Radio Access Bearer Release

C1


SGSN-initiated Deactivation Procedure


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GGSN



SGSNUTRANMS




C1


GGSN-initiated Deactivation Procedure


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GGSN



SGSNUTRANMS




C1


Summary

l The session management function includes the flowing


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g g

functions:

p PDP context activation function;

p PDP context modification function;

p PDP context deactivation function;



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