1 OWB000001O(Slides)GPRS Fundamental 20051207 B 2.0

HUAWEI TECHNOLOGIES CO., LTD. All rights reserved

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OWB000001 GPRS Fundamental

ISSUE 2.0

HUAWEI TECHNOLOGIES CO., LTD. Page 2All rights reserved

GPRS principle 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.


References

3GPP protocol 23060

3GPP protocol 29060

3GPP protocol 24008


Upon completion of this course, you

will be able to:

Describe the GPRS networking

structure

Describe the GPRS mobility

management procedure

Describe the GPRS session

management procedure


Chapter 1 GPRS Network StructureChapter 1 GPRS Network Structure

Chapter 2 Mobility ManagementChapter 2 Mobility Management

Chapter 3 Radio Resource managementChapter 3 Radio Resource management

Chapter 4 Session ManagmentChapter 4 Session Managment


GPRS Network Structure

What is GPRS?

General Packet Radio Service

Why GPRS?

In order to provide the data service to end user

GPRS network classification

GSM GPRS

UMTS GPRS

GPRS network background

GSM GPRS network reuse the existed GSM network

UMTS GPRS network just change the RAN side



FR

HLRHLRMSC/VLRMSC/VLR

BSSBSS

UTRANUTRAN

SGSNSGSN

SGSNSGSN

GGSNGGSN

BGBG

CGCG

PDN

SS7

GPRSBackbone

Gs Gr

Gb

Iu

Um

Um

Gp

Gi

Gn

Gn

ATM Ga

GMLCGMLC

Lg

Ga



Some Abbreviation

GPRS: General Packet Radio Service

BSS: Base Station Subsystem

UTRAN: UMTS Terrestrial Radio Access Network

SGSN: Service GPRS Support Node

GGSN: Gateway GPRS Support Node

CG: Charging Gateway

BG: Bordering Gateway

PDN: Packet Data Network



Some Abbreviation

MSC/VLR: Mobile Switch Center/Visitor Location Register

GMLC: Gateway Mobile Location Center

HLR: Home Location Register

EIR: Equipment Identity Register



Important Entity Function __ SGSN

Mobility management

− The mobility management functions are used to keep track of the current location of an MS within the PLMN or within another PLMN.

Session management

− Session Management (SM) function manages the PDP context of MS.

Routing and transfer

− SGSN performs routing and forwarding of service data between MS and GGSN.

Charging

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

Lawful Interception

NTP


GPRS Network Structure Important Entity Function __ GGSN

Session management

− Session Management (SM) function manages the PDP context of MS.

Routing and transfer

− GGSN performs routing and forwarding of service data between MS and internet.

Charging

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

Dynamic IP allocation

Service management

− Manage APN



Important Entity Function __ CG

Real-time collection of GPRS bills

Temporary storage and buffering of GPRS bills

Pre-processing of GPRS bills

Sending GPRS bills to the billing center


GPRS Network Structure Important Entity Function __ DNS

SGSN GGSN(A)

MS

BSS

GPRS backboneGPRS backboneGPRS backboneGPRS backbone

ISP AISP AISP AISP A

ISP BISP BISP BISP B

Internet/

IntranetGGSN(B)DNS

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



Important Entity Function __ HLR/AUC

Saving and updating GPRS subscriber subscription data

User authentication

Providing location/routing information and processing needed in mobility management and routing, for example

− Saving and updating user service SGSN number and address



Section 1 Attach and DetachSection 1 Attach and Detach

Section 2 Location ManagementSection 2 Location Management

Section 3 Security FunctionSection 3 Security Function







2G Network States Transition

PDU transmission

Implicit Detachor

Cancel Location

GPRS Attach

READY timer expiryorForce to STANDBY

GPRS Detach GPRS Attach

PDU reception

GPRS Detachor

Cancel Location

MM State Model of MS MM State Model of SGSN

IDLE

READY

STANDBY

IDLE

READY

STANDBY

READY timer expiryorForce to STANDBYorAbnormal RLC condition


Attach Procedure

(IMSI or PTMSI+RAI) (PTMSI)

(IMSI)

(Identity Type = IMSI) (IMSI)


Attach Procedure


Detach Procedure

Function

The GPRS Detach procedure allows an MS to inform the network that it does not want to access the SGSN-based services any longer

The GPRS Detach procedure allows the network to inform an MS that it does not have access to the SGSN-based services any more

The following three entity can initiate the detach procedure

MS

SGSN

HLR


Detach Procedure (MS Initiation)

2. Delete PDP Context Response

1. Detach Request

2. Delete PDP Context Request

3. Detach Accept

MS BSS/UTRAN GGSN SGSN

4. PS Signalling Connection Release


Detach Procedure

The MS is detached either explicitly or implicitly:

Explicit detach: The network or the MS explicitly requests

detach

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.







Routeing Area Update Procedure

RAU procedure will happen in the following two case:

MS entered a new Route Area

Periodic RAU ( after periodic timer expires)

Inter-SGSN RAU

The new SGSN find the old SGSN from the old RAI

Old SGSN stop downlink signaling, transfer MM context and PDP context to new SGSN

Tunnelling N-PDU to the new SGSN

Update PDP context and subscriber data


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)


Inter-SGSN RAU Procedure (2G)







Mobility Management Timer Function

Periodic RA Update Timer Function

Monitors the periodic routing area update procedure in the MS

Upon its expiry, the MS shall start a periodic routing area update procedure.

The length of the timer is set in SGSN; The value of the timer is sent to MS in attach accept message or routing update accept message

Mobile Reachable Timer Function

Upon the expiry of this timer, the MS is detached

This is reset and started when the state returns to STANDBY or PMM‑IDLE

The timer shall be slightly longer than the periodic RA update timer used by an MS

The length of the timer is set in SGSN Purge Timer Function

Allows the SGSN to inform the HLR that it has deleted the MM and PDP contexts of a detached MS.

The purge timer is set longer than the mobile reachable timer


Authentication Function

1a. Send Authentication Info

2a. Authentication and Ciphering Request

1b . Send Authentication Info ack

2b. Authentication and Ciphering Response

MS BSS/UTRAN HLR/Auc SGSN


P‑TMSI Reallocation

Function

The SGSN may reallocate the P‑TMSI at any time

The reallocation procedure can be performed by the

P‑TMSI Reallocation procedure

The P‑TMSI can be included in the Attach or Routeing Area

Update procedures.


P‑TMSI Reallocation

2. P-TMSI Reallocation Complete

1. P-TMSI Reallocation Command

MS BSS/UTRAN SGSN







Paging for GPRS (2G)

Function

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

downlink transfer to that MS

Paging move the MS state from STANDBY to READY.

Any uplink data from MS is a valid response to paging


Paging for GPRS (2G)

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, Channel Needed, QoS, DRX Parameters)

(Receive Ready or Information frame)







Session Management

Function

Establish and monitor a packet tunnel from MS to GGSN, and allocate system resource for the packet service.

Important Procedure

PDP Context Activation

PDP Context Modification

PDP Context Deactivation


Session Management

DNS

BTS

SGSN

MS

DNS

BSC

GGSN (B)BackboneBackbone

DNS

ISP BISP B

ISP AISP A

Corp.Network

Corp.Network

GGSN (A)

•APN_NI/APN_NI/

•Or APN_NI+APN_OIOr APN_NI+APN_OI

•APN_NI+APN_OI APN_NI+APN_OI ＝＝ GGSN IP addressGGSN IP address

•APN-NIAPN-NI


PDP Context

PDP Context

The PDP context is Packet Data Protocol context

PDP context contains all the information needed to transfer user data between MS and GGSN.

The context includes parameters such as Routing, QoS (Quality of Service), Charging ID etc.

PDP context exists in MS, SGSN, GGSN and RNC/BSS


MM Context and PDP Context

HLR

SGSNBSC

or RNC

MS GGSN GnGb/ IuUu

MM context

PDP context #1

.

.

PDP context #n

MM context

PDP context #1

.

.

PDP context #n

PDP context #1

.

.

.

PDP context #n


Important Concept __ PDP State

Deactivate PDP Contextor

MM state change to IDLEor PMM-DETACHED

Activate PDPContext

INACTIVE

ACTIVE PDP state

inactive： cannot transmit data

active： can transmit data


Important Concept __ PDP Type and PDP Address

PDP Type

IPV4

IPV6

PDP Address

Static IP

Dynamic IP


Important Concept __ QoS

QoS is quality of service

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

uch as the bit rate for downlink or uplink data transmission and

the reliability class and so on

It is end to end concept


Important Concept __ APN APN structure: APN_NI+APN_OI

huawei.com.cn.mnc<MNC>.mcc<MCC>.gprs

APNNetwork ID

APNOperator ID

•Operator ID : fixed extension, must end with “.gprs”

•Network ID shall not end with “.gprs”


Important Concept __ APN

MS SGSN

GGSN1

GGSN2

GGSN3

DNS

APN1

APN2

APN3

APN1=GGSN1 IP1

APN2=GGSN2 IP2

APN3=GGSN3 IP3

APN

APN GGSN IP

APN1

APN2

APN3

IP1


Activation Procedure

PDP context activation procedure

To establish a PDP context between the MS and the

SGSN, the GGSN


PDP Active Procedure (2G)

2G-GGSN

5. Activate PDP Context Accept

3. Create PDP Context Response

3. Create PDP Context Request

1. Activate PDP Context Request

2G-SGSNBSS

2. Security Functions

MS

4. BSS Packet Flow Context Procedures

C1

C2


Typical Application

E-mail from fixed to mobile network

BTS/NodeB

SGSN

MS

BSC/RNC

GGSNBackboneBackbone

ISPISP

Accessserver

Mailserver

e-mail

HLR


Typical Application

E-mail from mobile to fixed network

BTS/NodeB

SGSN

MS

BSC/RNC

GGSNBackboneBackbone

ISPISP

Accessserver

Mailserver

e-mail

HLR


Summary

In the whole GPRS fundamental, you

should remember some important

concept and the basic signalling

procedure

SummarySummary

www.huawei.com

Thank You

Documents

1 OWB000001O(Slides)GPRS Fundamental 20051207 B 2.0