Resource and Admission Control for Next Generation Networks Hui-Lan Lu, Ph.D. Q.4/13 Rapporteur

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ITU-T

International Telecommunication Union

Hui-Lan Lu, Ph.D.

Q.4/13 Rapporteur

Bell Labs, Lucent Technologies

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

Outline

ITU-T

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Complexity of NGN QoS

ITU-T Architecture for NGN Resource and Admission

Control

Configuration example

Use case

Summary

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

2

ITU-T

802.xx

Access

Complexity of NGN QoS

N G N

Cable

Domain 1

IntServ

Domain 2

DiffServ

Domain 3

MPLS-TE

Domain 4

Over-Prov

xDSL

Multi-Service Packet Transport

2G/3G

Wireless

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User-perceived QoS is end-to-end (cf. E.800)

NGN QoS is complex

NGN applications have

diverse

IP is

not

performance needs designed for

consistent

application performance

Diversity

— in an end-to-end path is common

Different levels of QoS support in

endpoints

Varying types of QoS support in the

transport

Multiple

provider domains

"

"

ITU-T Q.4/13 is addressing associated issues in its RACF work

Closely related efforts are under way in ETSI, 3GPPs, IETF, ATIS, etc.

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

3

Schematic View of ITU-T NGN Framework Architecture

ITU-T

Cf. Y.FRA (TD133 WP2/13, 01/2006)

3 rd

Party Applications

ANI

Control

Media

Management

Application/Service Functions

Service User

Profiles

Service stratum

Transport User

Profiles

Service Control

Functions

Network

Attachment

Control Functions

Resource & Admission

Control Functions

Transport Control Functions

End-User

Functions

Other

Networks

Transport Functions

UNI

NNI

Transport stratum

Resource and Admission Control Functions (RACF)

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Preserve the separation of services and transport

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Bridge services and transport to enable

dynamic application-driven

support for

performance assurance

and

network border control

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

4

ITU-T RACF Architecture

ITU-T

Cf. Y.

racf

(TD 81

-

WP4/13, 01/06)

Service Stratum

Service Control Functions

Rs

Transport Stratum

Network Attachment

Control Functions

Ru

Rp

Transport

Resource

Control

Function

Rd

Rt

Policy

Decision

Function

RACF

Ri

intra -

Rc

inter -

Transport

Enforcement

Function

Rn

Interconnection

Functions

Rw

Policy

Enforcement

Function

Transport Functions

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Policy Decision Function

service facing, transport independent

Transport Resource Control Function

service independent, transport dependent, network-segment specific

Policy Enforcement Function

typically part of border transport elements

RACF

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Augments native transport QoS support

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Preempting transport congestion at the

service control layer

Protecting ongoing premium traffic

Is applicable to all network-controlled applications (VoIP, IPTV, etc.)

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

5

Key Roles of RACF and Related Entities

ITU-T

Policy Decision Function

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Makes the overall admission decision based on policy and resource availability

(including path and enforcement point selection)

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Applies resource controls to the transport for bandwidth allocation, packet marking, gating, NAPT, etc.

Transport Resource Control Function

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Tracks transport resource usage and network topology

Resource-based admission control

Applies L2 resource controls to the transport

Policy Enforcement Function

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Enforces controls applied by PDF

Overall, RACF supports

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Relative

and

absolute

including

priority

QoS,

Endpoints of varied QoS control capabilities

Push

and

pull

models for policy installation

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Multiple transaction models for resource requests

Various resource management methods based on

accounting

,

measurement

and

reservation

Existing

and

emerging

transport QoS mechanisms

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

6

A Configuration Example

ITU-T

Service Control

Functions

Service Stratum

Transport Stratum

Rs

PD-FE

Network

Attachment

Control

Functions

Rw

Ru

Customer

Premises

Network

PE-FE

TRC-FE

Rc

Rt

Access Network

Rw

PE-FE

Ri

Rw

PE-FE

Rs

Rd

PD-FE

Rp

TRC-FE

Rt

Rc

Service Control

Functions

Core Network

Rw

Ri

PE-FE

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The PE-FE can reside in the

Gateway GPRS Support Node

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Packet Data Serving Node

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Session Border Controller

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Cable Modem Termination System

Access Node

Border Gateway

RACF enables incrementally-deployable end-to-end QoS solutions through per-domain control and inter-domain communication

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

7

Use Case: Link-Based Resource Management

ITU-T

CSCF

CSCF

CSCF- Call Session

Control Function

PD-FE

TRC-FE

Enterprise

Network

Softclient

IP Phone

Edge

Router

MPLS/DiffServ

Network

Core Router

Edge

Router

Enterprise

Network

Softclient

IP Phone

MPLS Path

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LSPs are set up a priori for routing traffic of a specific application

DiffServ is used for effecting desired treatment of traffic

RACF

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#

Measures link utilization per service class periodically

Formulates blocking policy upon link congestion for affected paths

Makes admission decision per policy

Configures edge routers for the admitted traffic

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

8

Summary

ITU-T

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Bridging service control and transport, RACF enables dynamic application-driven resource management

• Application admission decision taking into account resource availability

• Preempting transport congestion in the service control layer

Augmenting native transport QoS support, RACF can be applied edge-to-edge or end-to-end and be realized in various ways

All applications involving network control can make use of RACF for performance assurance and network border control

The initial Recommendation on RACF (

Y.racf

) is targeted for consent in July

• Selection and development of RACF protocols is ongoing

Next steps are to address open issues such as inter-PDF communication

(intra- and inter-provider) and coordination of transactions end-to-end

Draft Recommendations

Y.123.qos

and

Y.enet

apply RACF to specific Ethernet environments under development

Cooperation among related standards efforts across SDOs is desirable in order to achieve a consistent approach

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

9

List of Acronyms

ITU-T

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CSCF: Call Session Control Function

GPRS: General Packet Radio Service

LSP: Label Switched Path

NGN: Next Generation Networks

PD-FE: Policy Decision Functional Entity

PE-FE: Policy Enforcement Functional Entity

RACF: Resource and Admission Control Functions

SDO: Standard Development Organization

TRC-FE: Transport Resource Control Functional Entity

ITU-T Workshop “NGN and its Transport Networks“

Kobe, 20-21 April 2006

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