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LTE Evolved Packet Core

2

Your Tutor - Tony Wakefield

British Telecom – Joined 1981

– National Certificates in

– Telecoms

– Electronics

– BSc (Hons) Electronics & Physics

Royal Navy for 8 Years

Telecoms Training since 1996

Training Director for Informa Telecoms Academy

Worked with many companies – Vodafone, O2, Orascom, MTN, ZAIN, ATOS, Motorola, Nokia, Ericsson ……..

Programme Director for Tel Mini MBA and Distance Learning, + Technology Training (SS7, CAMEL, 3G, GPRS, GSM, Bluetooth, WiMAX ……)

Hobby - Cycling

3

Agenda

Core Network Evolution

LTE EPC Architecture

EPC Node Functions

LTE EPC Operation

LTE EPC Protocols

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Core Network Evolution

5

Fixed – Next Generation Network (NGN)

DSL

network

PSTN

H.248

MEGACO

SIGTRAN

SS7

TDM

IP based

xDSL for local loop

Reduced capex/opex

Secure

May use IMS for voice or

service delivery

6

UMTS Architecture with IP Core

Internet

Gi

Node Bs

Illustrates combined:

Release 4

MSC MGW and server

Release 5

GSNs and IMS

7

Single Core Network, Seamless Service Delivery

IMS - New subsystem to Control Services (IP Multimedia Subsystem)

Supports IP-based multimedia services (real-time and non-real time)

Based on IETF standards and protocols (e.g. SIP and SDP)

Fixed and mobile implementations

IP core network

IP Multimedia

Subsystem

GSM

GPRS

3G

Fixed

Line

Wi-Fi

WiMAX

Service

Control

Service

Transport Access

Technologies

SIP

8

EPC Concept

New subsystem

Supports IP-based multimedia services (real-time and non-real time)

Based on IETF standards and protocols (e.g. SIP and SDP)

Fixed and mobile implementations

Evolved Packet Core

(IP core network)

IP Multimedia

Subsystem

GSM

GPRS

3G

Fixed

Line

Wi-Fi

WiMAX

Service control

Service

Transport

3GPP Access

Technologies

SIP

LTE eUTRAN

Non - 3GPP Access

Technologies

9

LTE Architecture (High Level)

External Networks

IMS, MMS, WAP,

Media Centres Interworking with trusted

and non-trusted networks

EPC – Evolved Packet Core

New Core Network - All IP for efficiency

Designed to provide efficient data transport

Flexible QoS / Bearer Allocation

WLAN UMTS

eNBs UE

E-UTRAN

New Radio Access Network

Brings Greater Efficiency,

Flexibility and Speed

10

Terms – For Reference

LTE – Long Term Evolution

E-UTRAN – Evolved UMTS Terrestrial Radio Access Network

EPC – Evolved Packet Core

eNB – Evolved Node B

MME – Mobility Management Entity

SGW – Serving Gateway

PGW – Packet Data Gateway (Sometime PDN-GW)

UE – User Equipment

IMS – IP Multimedia Subsystem

11

EPC Anchor Functions

12

AAA and Diameter

Radius and Diameter are

similar in function

Diameter offers better

session control, proxying

and security

Internet

Accounting

Time connected

Data volume

Number of

packets Diameter

AAA

server

Network

access

server

Access

point

Access – Request

Access – Accept or Reject

Laptop

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LTE EPC Architecture

14

LTE Architecture (High Level)

External Networks

IMS, MMS, WAP,

Media Centres Interworking with trusted

and non-trusted networks

EPC – Evolved Packet Core

New Core Network - All IP for efficiency

Designed to provide efficient data transport

Flexible QoS / Bearer Allocation

WLAN UMTS

eNBs UE

E-UTRAN

New Radio Access Network

Brings Greater Efficiency,

Flexibility and Speed

15

LTE Architecture – E-UTRAN

eNBs UE

New Access Network Base Station - Evolved Node B

X2 interface for improved Handover and

Interference Management

Backhaul Connections are Critical, Capacity

Downlink Radio Interface Orthogonal Frequency Division Multiple Access

(OFDMA)

Improved Performance in Urban Areas

Multiple In Multiple Out (MIMO)

Uplink Radio Interface Single Carrier Frequency Division Multiple Access

(SC-FDMA)

Good Urban Area Performance

Designed for Good Battery Life

E-UTRAN

16

LTE Architecture – Evolved Packet Core (EPC)

EPC – Evolved Packet Core

New Core Network

All IP for efficiency

Self Organising Network (SON)

PGW – Packet Gateway

Connects to external networks

– Internet, IMS, WAP, MMS

Manages the IP session

MME – Mobility Management Entity

Overall control of UE and Data Sessions

Handle Handovers and Location Management

eNBs UE

SGW – Serving Gateway

Handles User Data

Controlled by the MME

17

LTE Architecture - Interworking

WLAN UMTS

eNBs UE

Interworking Defined interfaces for

interworking

UMTS/GPRS interworking

WiFi/WiMAX Interworking

Interworking with

Trusted/non-Trusted

18

LTE Architecture – Service Provision

External Networks

IMS, MMS, WAP,

Media Centres

WLAN UMTS

eNBs UE

19

LTE Architecture – Defined Interfaces

External Networks

IMS, MMS, WAP,

Media Centres

EPC – Evolved Packet Core

New Core Network

All IP for efficiency

Self Organising Network (SON)

WLAN UMTS

eNBs

UE

SGi S2

S5

S3,S4,S12

S1-U

S1-MME

S11

X2

E-UTRAN

New Radio Access Network

Brings Greater Efficiency,

Flexibility and Speed

Interworking with trusted

and non-trusted networks

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EPC Node Functions

21

SGW Functions

WLAN UMTS

SGi S2

S5

S3,S4,S12

S1-U

S1-MME

S11

Local Mobility Anchor point for

inter-eNodeB handover

Assist the eNodeB reordering

function during inter-eNodeB

handover

Mobility anchoring for inter-

3GPP mobility

ECM-IDLE mode downlink

packet buffering

Initiation of network triggered

service request procedure

Lawful Interception point in the

network

Packet routing and forwarding

Transport level packet marking

in the uplink and the downlink

22

PGW Functions

WLAN UMTS

SGi S2

S5

S3,S4,S12

S1-U

S1-MME

S11

Packet filtering, via deep

packet inspection

Allocation of UE IP

addresses

Downlink packet marking

Service level charging,

gating and rate enforcement

Mobility anchor 3GPP and

non-3GPP

Terminates the SGi interface

towards the PDN

23

MME Functions

WLAN UMTS

SGi S2

S5

S3,S4,S12

S1-U

S1-MME

S11

NAS signalling

Inter CN node signalling for

mobility between 3GPP access

networks

UE Reachability in ECM-IDLE

state Tracking Area list

management

PDN GW and Serving GW

selection

MME selection for handovers

with MME change

SGSN selection

Authentication

Bearer management functions

including dedicated

bearer establishment

Lawful Interception of signalling

traffic

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LTE EPC Operation

25

The Default Bearer

EPC

IMS IMS

VoIP App

LTE Network Establishes Initial Bearer

IP Address Allocated on registration

Must maintain an “always on” connection

Transfers SIP Signalling to IMS

Signalling (SIP)

26

The Dedicated Bearer

EPC

IMS IMS

VoIP App

LTE Network Dedicated Bearer established with application

activation

Bearer properties negotiated with EPC

Bearer properties include QoS parameters

Signalling (SIP)

Media (RTP)

27

QoS Class Identifier Values

EPS Bearer Properties

28

EPC Roaming Architecture – Home Routed

Traffic

29

EPC Roaming Architecture – Local Breakout

30

Policy and Charging Control Architecture

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LTE EPC Protocols

32

S1 Interface Protocols

PHY

L2

UDP/IP

GTP-U

PHY

L2

IP

SCTP

S1AP

NAS

IP (user) S1-U Tunnelling Protocol Encapsulates

User IP Packets

S1-MME SCTP provides reliable transfer

of signalling over S1

S1AP provides eNB control from

the MME

33

S5/S8 Interface Protocols

PHY

L2

UDP/IP

GTP-U

IP (user) S5/S8 Tunnelling Protocol

Encapsulates User

IP Packets

34

S11 Interface Protocols

PHY

L2

UDP/IP

GTP-C

S11 Provides bearer

control mechanisms

for the user pane

35

S6 Interface Protocols

PHY

L2

IP

SCTP

Diameter

S6 MME – HSS Interface

Exchange of user data

Diameter-SCTP replaces SS7

HSS

36

Thanks

telecomsacademy@informa.com

tony.wakefield@informa.com

www.telecomsacademy.com