Functional Architecture Model of NGN - ITU: Committed to ... · PDF fileFunctional Architecture Model of NGN ... Media Gateway Control Function MGW: Media Gateway ... the SIP proxy

ITU-T Workshop on “Next Generation Networks“Hanoi, Vietnam, 15-16 May 2006

International Telecommunication UnionITU-T

Functional Architecture Model of NGN

Functional Architecture Model Functional Architecture Model of NGNof NGN

Naotaka MORITASenior Research Engineer, Supervisor

NTT Service Integration Labs.

ITU-T Workshop on “Next Generation Networks“Hanoi, Vietnam, 15-16 May 2006 2

ITU-T A NGN is a packet-based network able to provide telecommunication services and able to make use of multiple broadband,

QoS-enabled transport technologies and in which service-related functions are independent from underlying transport-related technologies.

It enables unfettered access for users to networks and to competing service providers and/or services of their choice.

It supports generalized mobility which will allow consistent and ubiquitous provision of services to users.

Definitionof NGN(Rec.

Y.2001)

Target Standards Area

Generalized Mobility Convergence btw. Fixed & Mobile

Unrestricted Access Open Access I/F

Separation Services with Transport Architecture and Open API

QoS-enabled Transport

Multiple-BroadbandManageable Broadband

Definition & Features of NGN


ITU-T

• Transport functions assume packet-based integrated networks— The currently widely used IP protocol is the core protocol.• Service-related functions refer to basic and additional telephone connection functions and the

provision of functions inherent to services such as WWW and video distribution— Initial studies focused on session control functions for the implementation of IP telephony,

video chat, and video-conferencing using the SIP protocol as the core protocol.• The NGN separation model supports new independently developed technologies

and flexible system deployment and permits the formation of various businesses

NGN Transport Functions

NGN Service-Related FunctionsTelephone Services

Data Services (WWW, e-mail, etc.)Video Services (TV, movies, etc.)

Service-related functions and transport functions are separated into two strata

Internet Protocol(IP)

Anything and Everything

Everything(Any and All Network Technologies)

(Any/All Applicationse.g., voice, data, video)

Scope of the

Internet

“Service Stratum”

“Transport Stratum”

Reference: ITU-T Recommendation Y.2011 — General principles and general reference model for next generation networks

Characteristics of Next Generation Networks (NGN)


ITU-T

Y.NGN-FRA Figure 1. NGN architecture overview

Transport stratum

Service stratum

ControlMedia

Man

agem

ent

Func

tions

Management

ANI

Transport Control Functions

Resource and Admission

Control Functions

Network AttachmentControl Functions

NNIUNI

Note: UNI/NNI/ANI are not meant to represent any specific interfaces.(This type of note is written in TR-FRA word file.)

Application Support Functions & Service Support Functions

Applications

Transport Functions

End-UserFunctions

OtherNetworks

Service ControlFunctions

Service UserProfiles

Transport User Profiles


ITU-TIMS is a subsystem providing call processing and a variety of multimedia services in an IP-based packet-switching domain. — Provides voice, video, presence, messaging, conferencing, and other

services— Complies with IETF standardized session control (SIP); profiling— Independent of the access network— The application service platform itself is outside the scope of IMS

IMS is a subsystem providing call processing and a variety of multimedia services in an IP-based packet-switching domain. — Provides voice, video, presence, messaging, conferencing, and other

services— Complies with IETF standardized session control (SIP); profiling— Independent of the access network— The application service platform itself is outside the scope of IMS

Other IP/IMS Networks

Legacy/PSTN

Application Service Platform

IP Transport Network (IP-CAN)

IMS

IP-CAN: IP Connectivity Access Network

What is IMS?


ITU-T• Architecture centers on SIP proxy-equivalent Call Session Control Functions (CSCFs).• Employs a separation model that decouples media processing elements and their controlling

elements.• Links to transmission systems through a Gq interface.

AS: Application Server BGCF: Breakout Gateway Control Function CSCF: Serving CSCF HSS: Home Subscriber Server IP-CAN: IP-Connectivity Access Network ISC: IMS Service Control Interface MGCF: Media Gateway Control Function MGW: Media Gateway MRFC: Multimedia Resource Function ControllerMRFP: Multimedia Resource Function ProcessorP-CSCF: Proxy CSCF SLF: Subscription Locator Function

NGNs Based on IMS (from Y.IFN)

Other IP N

etworks

AS

I/S-CSCF

ChargingFunctions

« Core IMS»

Mw

Mx

Mr

MgMj

Mi

Mp MnGm

Gq'

ISC/MaCx Dx

DhSh

Ic

Rf/Ro

Rf/RoIb

Iw

Gq'

PSTN/ISD

N

MRFC MGCF

e2

Ie

Mw

MxMk

UE

Ut

BGCF

MxP-CSCF

NetworkAttachementControlFunction

Resource and Admission Control Function

IP Transport (Access and Core)

IBC-FE

NSIW-FESL-FESUP-FESAA-FE

MRP-FE TMG-FE

IBG-FE

SG-FE

Draft Recommendation Y-IFN: IMS for NGN


ITU-T

A

ProxyCSCF

ProxyCSCF

ServingCSCF

ServingCSCF

B

ProxyCSCF

ProxyCSCF

ServingCSCF

ServingCSCF

A’s Present Location (Hong Kong)

A’s Home Network(London)

B’s Home Network(New York)

B’s Present Location (Tokyo)

HSS-1 HSS-2

IP Backbone

Control signal

Voice, images, or other media

• In IMS nomenclature, the SIP proxy function is called the Call Session Control Function (CSCF).

• IMS defines a mobile-destination (roaming-destination) SIP server (proxy CSCF) in addition to the subscribing SIP server (serving CSCF) to allow authentication and QoS control by the mobile-destination network.

• IMS presumes that the serving CSCF cannot be accessed directly (a walled garden).

Roaming Implementation with Proxy CSCF


ITU-T

HSS

• In IMS, a CSCF is assigned to a user each time the user is registered (at power up). (This accounts for CSCF expansion, loading distribution, and risk distribution.)

• SIP signals from another network are first sent to the interrogating CSCF and then forwarded to the assigned CSCF.

• The interrogating CSCF has a topology hiding inter-network gateway function that can be deployed on the exit side as well.

• Fixed-network NGN discussions are permitting the deployment of a border gateway control function, which is different type of SIP proxy from an interrogating CSCF.

InterrogatingCSCF

InterrogatingCSCF

ServingCSCF

ServingCSCF

ServingCSCF

ServingCSCF

ServingCSCF

ServingCSCF

ServingCSCF

ServingCSCF

HSSHSS

Assignment Function(SLF)

Assignment Function(SLF)

InterrogatingCSCF

InterrogatingCSCF

Border GatewayControl FunctionBorder GatewayControl Function

I-CSCF: Interrogating CSCF

Topology HidingBy Encryption

Topology Hiding ByMessage Modification

Dynamic Assignment of SIP Proxies with Interrogating CSCF


ITU-T

SIP Server(S-CSCF)

SIP ASOSA AS CamelService

Environment

AS for third

parties

Separate Network

IMS

Application Layer

Service Control Layer HSS

APL of ASP

Web-typeAPL

Communication-typeAPL

IN-typeAPL

SDP (Service Delivery Platform)

• Implementation of new service functions(Examples: call-waiting, conferencing calls, ring-back music, IP centrex, calendar coordination)

• Three types of application servers that connect to SIP servers (S-CSCF):— OSA (Open Service Architecture Server)— SIP (SIP Application Server)— CAMEL (Camel Service Environment)• Additional studies are looking at the construction of a Service Delivery Platform (SDP) in the application layer

IMS and Applications


ITU-T

Y.NGN-FRA Figure 7. Application/Service support functions

A-3: APL-SCM-FE*

A-2: APL-GW-FE*

Applications

A-4: SS-FE

A-1: AS-FE*

Applic ation S uppo rt

Functions an d S ervice

Su pport Fu nctio ns

ANI

S-1: S-CSC-FE

S-4: SL-FES-15: MLT-FE

S-6: SAA-FE Service C

ontrol F

unction s

S-14: MRB-FE

S-13: MRC-FE

Note: * may include Authentication, Authorization, and Accounting

S-5: SUP-FE

A-S4A-S1 A-S2 A-S6A-S5A-S3

T-9: SG-FE

Transpor t Process ingF

unction s

End User Functions

A-U1 A-T1

UNI


ITU-T

Application

Scope of NGN

Man

agem

ent f

unct

ions

T-7:TrunkMediaGatew

ayFE

T-6:Inter-

connection Border

Gateway FE

S-6: S.Authentication & Authorization FE

S-8: Access GWControl FE

NACF RACF

LegacyTerminal

RGW

Customer Network

NGNTerminal

LegacyTerminal

ANIApplications

S-11: User Signaling Interworking FE

End-User Function

S-3: Interrogating Call Session Control FE

S-14: Media Resource Broker

FE

T-17: TransportResource Control FE

Access Packet Transport Functions

T-2: AccessNode FE

T-1: AccessMedia

GatewayFE

T-3: Edge Node FE

T-5:AccessBorder

GatewayFE

S-1: Serving Call Session Control FE

S-10: BreakoutGateway Control

FE

S-13: Media Resource

Control FE

Core Packet Transport Functions

T-8:Media

ResourceProcessing

FE

T-12: T. User Profile

FE

T-4: AccessRelay FE

S-2: Proxy Call SessionControl FE

T-10:Network Access

Configuration FE

S-4: Subscription Locator FE

S-5: S. User Profile FE

T-16: Policy Decision FE

S-12: Network Signaling

Interworking FE

T-9:Signallin

gGateway

FE

S-15:Multimedia

Service FE

NGN UNI

Other NGN

RACF

*

T-14: Access Management FE

T-15: Home GateWayConfiguration FE

T-11:T. Authentication &Authorization

FE

T-16: Policy Decision FE

T-17: Transport Resource Control FE

T-13: T. Locationmanagement FE

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

other IP MMNetwork

(e.g. IMS)

PSTN/ISDN

S-9: Media GW

Control FE

S-7: Interconnection Border Gateway

Control FE

Core transport

Access transport

Service control


ITU-T

Y.NGN-FRA Figure 8 - Transport and service configuration of the NGN

LegacyTerminals

Note: Gateway (GW) may exist in either Transport Stratum or End-User Functions.

*

LegacyTerminals

Transport Stratum

Service Stratum

End-UserFunctions

Application Functions

Core transport FunctionsNGN

Terminals

CustomerNetworks

Other N

etworks

Application Support Functions and Service Support Functions

Core TransportFunctions

Other N

etworks

EdgeFunctions

Access Transport Functions

ServiceControl

Functions

Network Access

Attachment Functions

Network Attachment Control Functions

(NACF)

Access NetworkFunctions

Resource and AdmissionControl Functions

(RACF)

UserProfile

Functions

T. UserProfileFunctions

GWGW

Other Multimedia ServiceComponents …Streaming ServiceComponent PSTN / ISDN Emulation

Service ComponentIP Multimedia Component&PSTN/ISDN Simulation

IP MultimediaService Component

S. UserProfile

Functions

GWGW

Applications


ITU-T

Y.NGN-FRA Appendix I Figure I.5: NGN example of service domains

TransitNetwork

Internet Operator A

IP ConnectivityAccess Network

Core TransportNetwork

TransitNetwork

InternetServices

InternetServices

Operator B

Core TransportNetwork

IP ConnectivityAccess Network

AccessNetworkLaptop

Core Network FirewallIMS

Services

Non-SIPServices

AccessNetwork

Core NetworkIMS

Services1

3

2

1

32： IMS services： Non SIP service： Internet service


ITU-T

Y.NGN-FRA Figure 2: Charging and Billing Functions

Online ChargingOffline Charging NGN

Functional Entity

ChargingTrigger

Function

ChargingCollectionFunction

OnlineChargingFunction

Billing Domain and BackendSystems

AccountManagement

Function

RatingFunction


ITU-T

Y.NGN-FRA Appendix II Figure II.1 – Multi-Layered Transport Stratum

IPSEC tunnel

IP

Node-1WLAN Access

Controller

Node-3Home Agent

App

IP-A

IP-B

IP-C IP-C IP-C

App

IP-B IP-B

IP-AIP-A

Node-2IPSEC GW

Host-1

Host-2

Mobile IP (using co-located CoA)

ServiceLayer

TransportLayer

Application protocols (e.g. SIP)

Nodes connected with a solid line (blue) are Layer-3 adjacent

Nodes connected with a short- dashed line (black) are Layer-2 adjacent

Nodes connected with a long- dashed line (red) are adjacent at the application layer(e.g. client/server or peer-to- peer application entities)

Legend:

Represents a routed IP network

AAA

AAA

AAA

IPNetwork-A

IPNetwork-B

IPNetwork-C

Solid arrow (green) indicates AAA & DHCP flows

WLAN


ITU-T

Y.NGN-FRA Appendix III Figure III.1: Locations of S/BC functions

ServiceProvider C

ApplicationProviderNetwork

EnterpriseNetwork

OrAccessNetwork

OrTransit

Network

CCSP: Call Control Signalling Path MP: Media Path

Logical Interfaces

ServiceProvider

A

CCSP

MP MP

CCSP

MP

CCSP CCSP

MP

CCSP

MP

CCSP MP

CCSP

MP

Logical Interfaces

Logical Interfaces

CCSP MPCCSP MP

CCSP MP

Logical Interfaces

ServiceProvider

B

CCSP MP

CCSP MP

ApplicationProvider Network

CCSP MP

CCSP MP

CCSP MP

CCSP MP

EnterpriseOr Home Network

EnterpriseOr Home Network

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Functional Architecture Model of NGN - ITU: Committed to ... · PDF fileFunctional Architecture Model of NGN ... Media Gateway Control Function MGW: Media Gateway ... the SIP proxy