325398709-0-EPC-Network-Fundamental.pdf

EPC Network Fundamental www.huawei.com

Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

References 3GPP TS23401 R8


Page1

Objectives Upon completion of this course, you will be able to: Describe the EPC network structure Describe the EPC Network interface and protocol Describe the EPC Network working procedures


Page2

Contents 1. EPC Network Structure 2. EPC Network Working Principle


Page3



Page4

Contents 1. EPC Network Structure 1.1 EPC Network Structure 1.2 EPC Network Interfaces


Page5

3GPP System Evolution 3GPP

GSM/ GPRS

UMTS: R99/R4/R5/R6/R 7

1.PS core network only support nonreal time services. 2. Voice services are carried in the CS domain. 3. Low efficiency of routes in forwarding data due to the over-layered networks. 4. Incapability of supporting multiple radio access systems

LTE/EPC: R8/R9/R10

1. The all-IP network contains the PS. Voice services are jointly provided by the PS and the IP Multimedia Subsystem (IMS). 2. Flattened network architecture. 3. Support of the multiple access technologies. 4. High data transmission rate: downlink 100 Mbit/s and uplink traffic 50 Mbit/s.


Page6

The Evolution of PS Network


Page7

EPS Network Structure Control plane

PCRF

HSS eNodeB

User plane MME S1-MME S6a

LTE -Uu

X2

S1-U

UE

LTE

Gx

S11

S1-MME eNodeB

Rx

Gxc

S1-U

S5

S-GW

SGi P-GW

SAE


Page8

Operator's IP Service

EPS Network Functions The EPS network perform the following logical functions : Network Access Control Functions. Packet Routeing and Transfer Functions. Mobility Management Functions. Security Functions. Radio Resource Management Functions. Network Management Functions.


Page9

GUL Network Structure Co-Site of the S-GW and P-GW UTRAN NodeB

SGSN S12

RNC

GERAN

S6a

S3

PCRF HSS

BTS

BSC/PCU MME S11

S4 Gx

Rx

S1-MME

LTE eNodeB

S1-U

SGi S-GW/P-GW


Page10

Operator's IP Services

GUL Network Structure Separate Installation of the S-GW and P-GW

UTRAN

SGSN S12

RNC

NodeB

S3

GERAN

PCRF

S6a HSS

BTS

BSC/PCU

S4

MME S1-MME

LTE eNodeB

Gx

S11

S1-U

S5 S-GW


Rx

SGi P-GW

Page11

Operator's IP Services

Functions of EPC Network Entity MME: mobility management entity Non-access stratum (NAS) signaling

MME selection for handovers with MME change

NAS signaling security

SGSN selection for handovers to 2G/3G access networks

Signaling interaction between core network (CN) Roaming nodes during an inter–3GPP access network handover Reachability of UEs in IDLE mode

Authentication

Tracking area (TA) list management

Bearer management

Selection of the P-GW and S-GW

Lawful interception of signaling traffic


Page12

Functions of EPC Network Entity SGW: serving gateway Functioning as the local mobility anchor point for inter-eNodeB handovers

Assisting the eNodeB reordering function during inter-eNodeB handovers by sending one or more "end marker" packets to the source eNodeB immediately after switching the path Supporting inter-operator charging based on subscriber and QoS class identifier (QCI) granularity Implementing downlink packet buffering and E-UTRAN triggered paging in ECM-IDLE mode

Functioning as the mobility anchor point for

Supporting packet routing and transfer

inter-3GPP handovers Performing lawful interception

Supporting transport level packet marking for uplink and downlink data


Page13

Functions of EPC Network Entity P-GW: packet data network gateway Packet filtering based on single user

Uplink and downlink gateway control based on traffic

Lawful interception

Uplink and downlink rate control based on traffic

IP address allocation for UEs

Uplink and downlink rate enforcement based on access point name-aggregate maximum bit rate (APN-AMBR)

Supporting packet marking for uplink and

Downlink rate enforcement based on

downlink data based on transfer priority

guaranteed bit rate (GBR)

Uplink and downlink charging based on traffic

DHCPv4 (server/client) and DHCPv6 (server) functions


Page14

Functions of EPC Network Entity HSS: home subscriber server Supporting authentication and registration for subscribers and downloading user profiles to the MME Supporting authentication and registration for non-3GPP subscribers and distributing user profiles to the AAA Providing roaming restriction Providing barring services Providing restrictions over access network types Implementing IPv4/IPv6 dual protocol stack Supporting Diameter-based IP networking


Page15

Functions of EPC Network Entity PCRF: policy control and charging rule function The PCRF is mainly used for prescribing rules for policy and charging control. The PCRF is responsible for terminating the Rx interface and the Gx interface.


Page16

HUAWEI LTE-EPC Solution HSS

SGSN GPRS

Control plane User plane BTS

BSC/PCU PCRF

UMTS NodeB

RNC

MME

Operator Service Network

LTE S-GW

eNodeB

P-GW

CDMA BTS

BSC/PCF

PDSN/HSGW


Page17

Corporate Services

Contents 1. EPC Network Structure 1.1 EPC Network Structure 1.2 EPC Network Interfaces


Page18

EPC Network Interfaces Control plane

PCRF

HSS eNodeB

User plane MME S1-MME S6a

LTE -Uu

X2

S1-U

UE

LTE

Gx

S11

S1-MME eNodeB

Rx

Gxc

S1-U

S5

S-GW

SGi P-GW

SAE


Page19

Operator's IP Service

Control Plane Protocol Stacks NAS

NAS RRC

RRC

S1-AP

S1-AP

PDCP

PDCP

SCTP

SCTP

RLC

RLC

IP

IP

MAC

MAC

L2

L2

L1

L1

L1

L1

UE

LTE-Uu

eNodeB


S1-MME

Page20

MME

User Plane Protocol Stacks Application IP

IP Relay

Relay

PDCP

GTP-U

GTP-U GTP-U

PDCP

GTP-U

RLC

RLC

UDP/IP

UDP/IP

UDP/IP

UDP/IP

MAC

MAC

L2

L2

L2

L2

L1

L1

L1

L1

L1

L1

LTE-Uu

UE

S1-U

eNodeB

S5/S8 a

Serving GW


SGi

PDN GW

Page21

S1 Interface S1-MME

MME

S1-U S-GW

eNodeB

S1-AP

S1-AP

SCTP

SCTP

GTP-U

GTP-U

UDP/IP

UDP/IP

IP

IP

L2

L2

L2

L2

L1

L1

L1

L1

eNodeB

S1-MME

MME

eNodeB


S1-U

Page22

S-GW

S6a Interface S1-MME

S6a

HSS

MME

eNodeB

Diameter

Diameter

SCTP

SCTP

IP

IP

L2

L2

L1

L1 S6a

MME

HSS


Page23

S10 Interface S10 MME S1-MME

S6a

HSS

MME

eNodeB GTP-C

GTP-C

UDP

UDP

IP

IP

L2

L2

L1

L1 S10

MME


MME

Page24

S11 Interface S10 MME S1-MME

MME

eNodeB GTP-C

GTP-C

UDP

UDP

IP

IP

L2

L2

L1

L1 S11

MME

S6a S11

S-GW

S-GW


Page25

HSS

S5/S8 Interface

MME

S11

S1-U

eNodeB PLMN1

S5

S-GW

S8

P-GW

PLMN2 P-GW


Page26

S5/S8 Interface: 3gpp 23401 3GPP23.401(3gpp access): An S5/S8 interface based on GTP. The signaling plane runs the GTPv2 protocol and the user plane runs the GTPv1 protocol. GTP-C

GTP-C

GTP-U

GTP-U

UDP/IP

UDP/IP

UDP/IP

UDP/IP

L2

L2

L2

L2

L1

L1

L1

L1

P-GW

S-GW

S-GW

GTP based S5/S8

Control plane Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

GTP based S5/S8

User plane Page27

P-GW

Gx/Gxc Interface

PCRF Gxc

S-GW

Gx

Diameter protocol application

Diameter protocol application

Diameter base protocol

Diameter base protocol

TCP

TCP

IP

IP

L2/L1

L2/L1

P-GW

PGW/SGW


Gx/Gxc

Page28

PCRF

SGi Interface AAA Server SGi

P-GW

Web Server PDN


Page29



Page30

Contents 2. EPC Network Working Principle 2.1 General Service Process 2.2 Identity of EPC Network 2.3 Mobility Management Procedure 2.4 Session Management Procedure


Page31

Typical Packet Service

MME

1

ICP/ISP internet

eNodeB

2

S-GW

P-GW Signaling Data


Page32

Typical Voice Service IMS domain EPC Signaling IMS Signaling SS7 Signaling Data (VOIP)

MGCF 3

CSCF

IMS-MGW 4

MME

1

SS7

2 MSC eNodeB

4

S-GW

PLMN

P-GW EPC


Page33

Roaming: Home Routed VPLMN Gb

HPLMN HSS

SGSN

PCRF

GERAN Iu S3

S4 S6a

Gx

Rx

S12 UTRAN S11 S1-C

MME

S8

SGi

S1-U E-UTRUAN

S-GW


PDN-GW

Page34

Operator’s IP Service

Roaming: Local Breakout VPLMN Gb

HPLMN

SGSN

HSS

H-PCRF Rx

GERAN Iu S3

S4


S9

S6a V-PCRF

S12 UTRAN S11 S1-C

Gx

MME

S5

SGi

S1-U E-UTRUAN

S-GW


PDN-GW

Local Breakout with Home Operator's Application Functions only


Page35

Roaming: Local Breakout VPLMN Gb

HPLMN

SGSN

HSS

H-PCRF


GERAN Iu S3

S4

S9

S6a V-PCRF

S12

Rx

UTRAN S11 S1-C

Gx

MME

S5

SGi

S1-U E-UTRUAN

S-GW


PDN-GW

Local Breakout with Visited Operator's Application Functions only


Page36



Page37

Identity of EPC Network MME

MMEI= MME Group ID+MME Code

TAI=MCC+MNC+TAC TA List

TA List

TA 1

TA 2

TA 1

TA 2

CELL1 CELL2

CELL3 CELL4

CELL1 CELL2

CELL3 CELL4

IMSI MSISDN GUTI=GUMMEI+M-TMSI =MCC+MNC+MMEI+M-TMSI Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Page38



Page39

Subscriber State Management Subscriber state EMM: EPS Mobility Management EMM-DEREGISTERED EMM-REGISTERED

ECM: EPS Connection Management ECM-IDLE ECM-CONNECTED


Page40

EMM State Detach, Attach Reject, TAU reject, E-UTRAN interface switched off due to Non-3GPP handover, All bearers deactivated EMM-DEREGISTERED

EMM state in UE

EMM-REGISTERED Attach accept

Detach, Attach Reject, TAU reject, All bearers deactivated EMM-DEREGISTERED

EMM state in MME

EMM-REGISTERED Attach accept TAU accept for a UE selecting E-UTRAN from GERAN/UTRAN


Page41

ECM State RRC connection released ECM-CONNECTED

ECM-IDLE

ECM state in UE

RRC connection established

S1 connection released ECM-CONNECTED

ECM-IDLE S1 connection established


Page42

ECM state in MME

MM and EPS Bearer Context MM context MME

Subscription information

HSS

EPS bearer context

EPS bearer Subscription context

ICP/ISP internet MM context

S-GW

P-GW

EPS bearer context

EPS bearer context

EPS bearer context


Page43

Signaling Data

Mobility Management Procedures Main mobility management procedures: Attach procedure Tracking area update procedure Detach procedure


Page44

Attach Procedure Function of attach procedure: The UE register to the EPS network. The always-on IP connectivity for UE/users of the EPS is enabled by establishing a default EPS bearer during Network Attachment. The MM context and EPS bearer context will be created in the MME and UE. The EPS bearer context will be created in S-GW and P-GW.


Page45

Attach Procedure eNodeB

New MME Old MME

HSS

S-GW

P-GW

1. Attach request 2. Identification req/rsp 3. Identity req/rsp 4. Security function 5. Update location request 6. Cancel location /Ack 7. Update location Ack 8. Create default bearer req 9. Create default bearer req 10. Create default bearer rsp


Page46

Attach Procedure eNodeB

New MME Old MME

HSS

S-GW

11. Create default bearer rsp 12. Attach accept 13. Radio bearer establish 14. Attach complete 15. Update bearer request 16. Update bearer response 17. Uplink and downlink data


Page47

P-GW

Location Information Storage HSS

MME1

MME IP address

MME2

Tracking Area list Tracking Area ID E-UTRAN Cell Global Identity

Tracking Area list Tracking Area ID


Page48

TAU Procedure S-GW2

S-GW1

MME2

MME1

TA list 1

TA list 2

Periodic TAU

MME3

TA list 4

TA list 3

Inter MME TAU with SGW change

Intra MME TAU


Inter MME TAU without SGW change

Page49

Inter TAU without SGW change eNodeB

New MME Old MME

HSS

S-GW

P-GW

1. TAU request 2. Context request 3. Context response 4. Security function 5. Context Ack 6. Update bearer request 7. Update bearer request 8. Update bearer response 9. Update bearer response


Page50

Inter TAU without SGW change eNodeB

New MME Old MME

HSS

S-GW

10. Update location request 11. Cancel location 12. Cancel location Ack 13. Update location Ack 14. TAU accept 15. TAU complete


Page51

P-GW

Inter TAU with SGW change eNodeB

New MME Old MME

HSS New S-GW Old S-GW

P-GW

1. TAU request 2. Context request 3. Context response 4. Security function 5. Context Ack 6. Create bearer request 7. Update bearer request 8. Update bearer response 9. Create bearer response


Page52

Inter TAU with SGW change eNodeB

New MME Old MME

HSS New S-GW Old S-GW

10. Update location request 11. Cancel location 12. Cancel location Ack 13. Update location Ack 16. TAU accept 17. TAU complete

14. Delete bearer request 15. Delete bearer response


Page53

P-GW

Detach Procedure The detach procedure is used in the following scenarios: A UE is detached from the EPS service. A UE is disconnected from the last PDN connection. The network informs a UE that the UE cannot access to the EPS.

A UE can be detached explicitly or implicitly. Explicit detach Implicit detach


Page54

UE Initiated Detach Procedure eNodeB

MME

S-GW

P-GW

1. Detach request 2. Delete bearer request 3. Delete bearer request 4. Delete bearer response 5. Delete bearer response 6. Detach accept 7. Signaling connection release


Page55

Security Function 2G

3G

EPC

Authentication

Single-directional authentication

bi-directional authentication

bi-directional authentication

Security vectors

Triplet (RAND, Sres, and Kc)

Quintet (RAND, XRES, CK, IK, and AUTN)

New EPS security vectors (RAND, AUTN, XRES, and KASME). The UMTS and EPS authentication vectors are separated.

Integrity protection

No

Yes

Yes

SIM compatibility

N/A

Yes

No

Layered security architecture

No

No

Provides protection for the NAS layer and the AS layer separately. Manages the keys in the NAS and AS layers separately. Performs the algorithm negotiation for the NAS and AS layers separately.


Page56

Authentication Vector EPS authentication quaternary RAND: Random Challenge AUTN: Authentication Token XRES: Expected Response Kasme: Ciphering key


Page57

Authentication Procedure MME

HSS

1. Authentication data request 2. Authentication data response 3. User authentication request 4. User authentication response


Page58

EPS Security Architecture UE

MME NAS

Ciphering/integrity

NAS

NAS eNodeB

RRC

RRC Ciphering/integrity

RRC

UP Ciphering PDCP

PDCP


Page59

NAS/AS Security Mode Procedure eNodeB

MME

1. NAS security mode command 2. NAS security mode complete

1. AS security mode command 2. AS security mode complete


Page60



Page61

Multiple-PDN connectivity Server

PDN connection 1: APN1

Intranet P-GW ICP/ISP

S-GW

internet

PDN connection 2: APN2 P-GW PDN connection 3: APN3

Server Intranet S-GW

P-GW

Wap server

PDN connection 4: APN4


Page62

Wap network

EPS Bearer One PDN connection include one default EPS bearer, and zero or several dedicated EPS bearer. PDN connection 1 Default EPS bearer Dedicated EPS bearer 1 Dedicated EPS bearer 2 P-GW

S-GW EPS bearer

Radio bearer

eNodeB

S1 bearer

S-GW S5/S8 bearer


Page63

P-GW

Session Management Procedure EPS bearer management procedure Bearer activation procedure Bearer modification procedure Bearer deactivation procedure

PDN connection management procedure (UE support for multiple PDN connections): UE requested PDN connectivity procedure UE or MME requested PDN disconnection procedure


Page64

P-GW Initiated Dedicated Bearer Activation eNodeB

MME

S-GW

P-GW

1. Create dedicated bearer request 2. Create dedicated bearer request 3. Session management request 4. Creation of bearer of E-UTRAN 5. Session management response 6. Create dedicated bearer response 7. Create dedicated bearer response


Page65

P-GW Initiated Bearer Modification With QoS Update eNodeB

MME

S-GW

P-GW

1. Update bearer request 2. Update bearer request 3. Session management request 4. Update of bearer of E-UTRAN 5. Session management response 6. Update bearer response 7. Update bearer response


Page66

PDN GW Initiated Bearer Deactivation eNodeB

MME

S-GW

P-GW

1. Delete bearer request 2. Delete bearer request 3. Deactivate EPS bearer context request 4. Release of bearer of E-UTRAN 5. Deactivate EPS bearer context accept 6. Delete bearer response 7. Delete bearer response


Page67

UE Requested Bearer Resource Modification eNodeB

MME

S-GW

P-GW

1. Request bearer resource modification 2. Request bearer resource modification 3. Request bearer resource modification

4. Dedicated bearer activation, or dedicated bearer modification, or dedicated bearer deactivation procedure


Page68

UE Requested PDN Connectivity Procedure eNodeB

MME 1. PDN connectivity request

S-GW

P-GW

2. Create default bearer request 3. Create default bearer request 4. Create default bearer response 5. Create default bearer response 6. PDN connectivity accept 7. Creation of bearer of E-UTRAN 8. PDN connectivity complete 9. Update bearer request 10. Update bearer response Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Page69

UE Requested PDN Connectivity Procedure eNodeB

MME 1. PDN connectivity request

S-GW

P-GW

2. Create default bearer request 3. Create default bearer request 4. Create default bearer response 5. Create default bearer response 6. PDN connectivity accept 7. Creation of bearer of E-UTRAN 8. PDN connectivity complete 9. Update bearer request 10. Update bearer response Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Page70

UE Requested PDN Disconnection Procedure eNodeB

MME

S-GW

P-GW

1. PDN disconnection request 2. Delete bearer request 3. Delete bearer request 4. Delete bearer response 5. Delete bearer response 6. Release of bearer of E-UTRAN


Page71

Summary The EPC network is composed of: MME, S-GW, P-GW

The main working principle of EPC network are: Mobility management procedure Session management procedure


Page72

Thank you www.huawei.com

325398709-0-EPC-Network-Fundamental.pdf

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