IMS based NGN IMS based NGN Architecture Architecture and its - - PowerPoint PPT Presentation

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6

I nternational Telecom m unication Union

ITU-T

IMS based NGN IMS based NGN Architecture Architecture and its application and its application

Dick Knight

BT Group plc

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 2

ITU-T

Outline

• IP Multimedia S

ubsystem

• Overview & Key Features
• Use in NGN
• Benefits
• Support for PSTN/ ISDN Replacement
• Simulation
• Emulation
• Overall Architecture
• ITU-T S

G13, ETS I TIS PAN & BT 21CN

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 3

ITU-T

I P Multim edia Subsystem

• S

IP-based control system to enable media- agnostic service delivery in IP networks

• Secure registration
• Secure communications
• Location independence
• Separation from Service providing application
• Specified by 3GPP
• Control system for a flexible service delivery

platform

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 4

ITU-T

Key Elem ents

UE

P-CSCF S-CSCF AS HSS Transport Network NACF & RACF

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 5

ITU-T

Key Elem ents Functionality 1

• UE – User Equipment
• P-CS

CF

• Proxy Call Session

Control Function

• First contact point
• Forward SIP messages

from UE to S-CSCF and vice-versa

• Generation of CDRs.
• Maintain security

association to UE

• Authorisation of

bearer resources

• HS

S Home S ubscriber S erver

• Mobility Management
• User security
• Service Provisioning &

authorisation support

• Call / Session

establishment support

• GUP Data Repository
• Identification handling
• Access authorisation
• Application Services

S upport

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 6

ITU-T

Key Elem ents Functionality 2

• S
• CS

CF

• Serving Call Session

Control Function

• Control for registered

UE sessions

• May behave as Proxy

Server or User Agent

• Interaction with

Services Platforms

• Provide endpoints

with service event related information

• Obtain Address of

entry point for network serving the destination user

• Modify t he SIP request

according to HSS and service control interactions

• Perform preference

and capability matching

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 7

ITU-T

I MS in NGN

• Performs Service Control Functions
• Within the service stratum
• Meets the requirements of Y.2001
• Flexible approach to services
• Service delivery using Internet applications,

services and protocols

• Provides inherent mobility support
• Already exists!
• BUT – specific to IP Connectivity Access

networks

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 8

ITU-T

RACF NACF

I MS Adaptations in NGN

S pecific adaptations to NGN – generic access

IMS

UE Transport Network

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 9

ITU-T

I MS Adapted to NGN

• Control of IP Transport Networks (admission

control, QoS, authentication, etc.)

• Co-ordination of multiple control

components to a single core transport

• Interworking and interoperability with

legacy and other networks

• Mutual de-coupling of applications from

session/ call control and transport

• Access technology independence of

session/ call control and applications

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 1 0

ITU-T

Architecture of I MS for NGN

Figure 1 of draft ITU-T Recommendat ion Y.IFA

MGW MGCF CSCF BGCF CSCF BGCF SLF P-CSCF MRFP MRCF

Mk Mi Mw Dx Cx Mr Mg Mw Mj PSTN Mn Mp Mm Mb Gq Gm Sh Dh ISC

HSS

Other IP Multimedia Networks

PSTN IP Connectivity Access Network

Mb

UE

AS

Mb Mb

(AAA+DB)

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 1 1

ITU-T

PSTN/ I SDN Replacem ent

Simulation

• Interactions between

AS and UE provide “ PSTN/ ISDN-like” services to NGN Users

• IP “ Terminals”
• Includes terminal

adapters

• Network and UE based

services

• Example use of IMS

Emulation

• PS

TN/ IS DN service capabilities and interfaces using adaptation to an IP infrastructure

• Legacy user equipment

and interfaces unchanged

• Two approaches:
• Call Server

(S

• ftswitch)
• IMS
• based

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 1 2

ITU-T

S-CSCF AS (ISUP-aware) HSS AGCF

H.248

I MS-Based Em ulation

Transport Network NACF & RACF

PSTN ISDN UE

Access Media G/W

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ITU-T

Advantages of I MS PES

• Preserves common interface to RACS &

transport network

• Common service control functions
• Common Routing and configuration data

between emulated PS TN/ IS DN Users and NGN Users

• Economy of scale
• Consider effects of reducing numbers of

emulated users

• Provision of advanced services

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 1 4

ITU-T

Service Control Architecture

ANI Application Application Support Functions & Service Support Functions (may include own Authentication, Authorization and Accounting) ANI Applications Application Support Functions & Service Support Functions (may include own Authentication, Authorization and Accounting)

• ther IP MM

Network (e.g. IMS) PSTN/ISDN Internet Other NGN

Access Packet Transport Functions NACF End-User Functions Core Packet Transport Function RACF

NGN UNI Subscription User Authentication & authorisation User Signalling I/W

Media Res. Broker

Media G/W Control Subscription User Subscription Locator User Profile Network Sig. Interworking Multimedia Service FE I/C Border G/W Control I-CSCF S-CSCF Breakout G/W Control Media Resource Control P-CSCF Access Gateway Function Based on Y.FRA Fig. 3

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 1 5

ITU-T

ETSI TI SPAN Architecture

(* apart from IMS-based PSTN Emulation)

Other IP Networks

IP Transport (Access and Core)

I-BGF

UPSF P-CSCF I/S-CSCF BGCF SLF

Charging Functions

IWF PSTN Emulation (R2)

Mw Mw/Mk/Mm Mr Mg Mj Mi Mp Mn Gm Gq' ISC Cx Dx Dh Sh Ic Rf/Ro Rf/Ro Ib Iw Gq'

PSTN/ISDN SGF MRFC MGCF

MRFP

e4 Ie Mw

IBCF

Mk Mk

Application Servers

Rf/Ro

AGCF

e2 P1 P2 P3

UE

CNG

MG

IMS / PSTN Simulation

Gq'

SPDF

A-RACF

Resource & Admission Control RACS

SPDF

Network Attachment Subsystem

Re Ia

RCEF BGF Ut Ut T-MGF

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6 1 6

ITU-T

BT 2 1 CN Architecture

H248

POTs

OSA AS Call Application Servers

SIP Application Server

AS AS AS SIP Stack

SIP Application Servers

OSA AS

AE

OSA SCS MRFC MGCF HSS plus

ISC

Mr Mp Mg Mn P- CSCF I-CSCF Gq’ Gm Mw Sh S-CSCF Mw SCIM

ISC

Ia

IMS

Rq SPDF Re SGF Cx BCF SPDF Mw P2 Presence Messaging Other TDM Networks 3rd Party Applications & Services Other IP Networks

External Application s

IAD Media Server MPLS/IP Network Media Gateway Border Gateway WiMax/WLAN PSTN BRAS Border Gateway Backhaul

M S A N

Other IMS C7

SBR (ENUM) PSTN Call Server

CAC

BWM A-RACF

Metro and Core MSAN and Access

Service Assembly

AGC F SIP e4 e2 e1

I TU-T W orkshop “NGN and its Transport Netw orks“ Kobe, 2 0 -2 1 April 2 0 0 6

I nternational Telecom m unication Union

ITU-T

Thank You Thank You