1 converging telco and internet standards peter darling manager, international & ngn, australian...

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Converging Telco and Internet Standards

Peter DarlingManager, International & NGN,

Australian Communications Industry Forum

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Things Change!

• Ten years ago The Public Switched Telephone Network (PSTN)

was just completing the transition to digital The Internet was starting to move from academia

• Three years ago Dot.com mania ruled It was “reliably” forecast that the Internet was about

to take over as the sole communications medium

• Today There is a strike of capital, but convergence is becoming a reality

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In the Future

• Telephony and multi-media may be just another application over the Internet, but

• There will need to be changes to support user requirements, based current expectations.

• To make this happen, there needs to be Substantial resource investment, and Substantial standards work

• Much current telco standards work directly relates to NGN (next generation networks)

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Network Generations

Fixed Network Mobile Data

Analogue PSTN Analogue Mobile(AMPS, NMT)

X.25 Packet

Digital PSTN Digital Mobile (GSM, CDMAOne)

Frame Relay

Internet

“Carrier Grade IP” 3G(CDMA2000, UMTS)

“Carrier Grade IP”

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2G Mobile

PSTN

• The PSTN/ISDN is based on 64 kbit/s digital connections, with a separate “common channel” signalling system• Access may be analogue (telephony), 64 kbit/s digital

(ISDN) or low speed digital (mobiles)• The network establishes an end-to-end digital connection for

the duration of each call

• The PSTN/ISDN is designed for high reliability, specified at the national level and connecting to form a global network,

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ISP“The Internet”

(best-endeavours network)

ISP

• The (public) Internet is based on the set of protocols defined by the Internet Engineering Task Force (IETF)• The primary protocol is the Internet Protocol (IP) which

describes a simple connectionless packet protocol able to operate over a range of media

• Other protocols work in association with the IP, for example, TCP to assist reliable end-to-end operation

• The Internet is defined by the Internet protocols rather than by a standardised architecture

• The Internet provides open interfaces, supporting rapid innovation

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Telco Networks• 64 kbit/s circuit switching• Well defined architecture,

fixed and mobile.• Designed for high reliability

and QoS• Specified at national level

growing to global• Main area for national

regulation

Dumb terminal, smart network

Current Internet• Packet switching over

diverse media• Defined by protocols rather

than architecture (TCP/IP)• Specified at global level• Best endeavours network –

no QoS guarantee• Open interfaces support

rapid innovation

Smart terminal, dumb network

Next Generation Networks Largely Packet based (IP & ATM), with necessary extensions to give a level of service equal to or better than current carrier networks

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Network Evolution

• There are different paths (not mutually exclusive) by which “an NGN” could evolve: Interconnection of enterprise IP VPNs IP expansion of existing carrier networks New IP-based networks providing integrated

service Addition of QoS support to the existing public

Internet

• What is the underlying demand, the business case and the likely timing? (The economics of adding QoS to the existing Internet do not seem compelling.)

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Quality of Service Provision• Future networks need to provide adequate Quality of

Service to support real-time interactive services (e.g. voice)

• There has been extensive work on “adding” QoS to the Internet

• Implementation of QoS can be standards driven (primarily IETF work), based on proprietary approaches provided by traffic segregation and traffic engineering (over-

provision of underlying resources)

• Almost all work in the IETF has been directed with a single network rather than across networks (NNI or inter-domain)

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Domain 3

Domain 2Domain 1

Client

ClientTransport Network Transport Network

Service networkService network

ServiceDomain

ServiceDomain

• Carrier networks consist of multiple domains

• each domain may have its own policies• each domain may have its own commercial goals• and possibly its own protocols & transport

Carrier Networks are not homogeneous

Relevant interfaces

Source: ITU-T SG 11

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Why Change?

The current circuit switched PSTN provides good service. What are the likely drivers for change to a packet-based network?

• Flexibility The PSTN is based on carrying 64 kbit/s circuits.

• Services at bit-rates below this can be carried (but not efficiently)

• Services at bit-rates above this can only be carried by combining 64 kbit/s circuits

Open interfaces supporting innovation

• Economics

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“Carrier Grade” IP-based Networks

2G Mobile

PSTN



ISP

ISP

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What is Needed for “Carrier Grade IP”?

• The current Internet Does not provide differentiated quality connections Queues packets at peak times for maximum

efficiency

• If the Internet is not congested, real-time (e.g. voice) packets can be delivered, but if there is congestion, real-time services cannot be supported reliably.

• There is a need for connection-oriented support to provide a required level of QoS for the duration of a connection (or, in telco terms, a call)

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To provide QoS…..

• An underlying backbone transport is required (for example, by SONET/SDH over optical fibre or radio)

• Backbone resource control protocols such as GMPLS with RSVP-TE or CR-LDP can be used to provide support for resource allocation

Backbone transport

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To provide QoS…..

• It is then necessary to establish specific support for end-to-end connections for the duration of the connection/call.

• This can be provided by MPLS enabled routers, or by the use of the virtual circuit capabilities of ATM

Backbone transport

Bearer Control

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To provide QoS…..

• Per call (or session) call control is needed for the duration of each call, to set up, supervise and clear-down.

• Possible protocols include BICC (from the ITU-T) SIP (from the IETF) H.323 (from the ITU)

Backbone transport

Bearer Control

Call Control

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To provide QoS…..

• SIP and H.323 are end-to-end protocols• An alternative approach is to use centralised control from a

Media Gateway Controller / Softswitch, combining bearer and call control Megaco/MGCP H.248 has been developed by IETF and ITU

Backbone transport

Bearer Control

Call Control

Service/application

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QoS Support

• Caller must specify requirements• Access network and subsequent networks must provide the

required QoS for the duration of the call

Current Internet protocols can support this within one network, but not across different networks

Translation of Service Request to QoS/Flow RQ

Translation of QoS/Flow RQ to Service Request

Signalling Message (with QoS/Flow RQ message)

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“Carrier Grade” IP-based Networks

ISP

2G Mobile

PSTN



ISP

ISP

? ?

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End-to-End Connectivity?

There is no shortage of possible approaches – and they are all in use!

The problem How to guarantee end-to-end service with the required QoS across

multiple networks using incompatible implementations[the subject of current international work]

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Today’s Network Architectures

• Multiple, interworked, interdependent networks• Diversity of control and management architectures• Capacity and performance bottlenecks• Each network has its own control plane and management plane

• Multiple, interworked, interdependent networks• Diversity of control and management architectures• Capacity and performance bottlenecks• Each network has its own control plane and management plane

IP/MPLSNetworks

PSTN/ISDN

Radio Access

Networks

EthernetNetworks

Wireless Access

Frame Relay

Networks

IWF

IWF

IWF

IWF

IWF

IWF

IWF

ATM Networks

IWF

IWF

Source: ITU-T SG 13

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Near Term Evolution

ATM Networks

IWF

PSTN/ISDN Rec. Q.2931, PNNI

Frame Relay

Networks

IP-based Networks

PSTN/ISDN OSF & NM, M series Rec.

Rec. Y.1310

IETF RFCs

Q & X series Rec.

IWF

IWF

Rec. I.555Rec. I.580

Rec. Q.931

ATM OSF & NM, M series Rec.

SNMP based

FR OSF & NM

OSF = Operating Support Function

For• Convergence on ATM core

networking enables initial stage of unified management and control

• Enhanced performance and QoS capabilities for multi-services over common platform

For• Convergence on ATM core

networking enables initial stage of unified management and control

• Enhanced performance and QoS capabilities for multi-services over common platform

PSTN/ISDN

IWF

SS7 Network

Rec. I.580Rec. Q.700 series

Against• Lack of service transparency

between IP based services and ATM/PSTN services

Against• Lack of service transparency

between IP based services and ATM/PSTN services

Wireless access

IWF

Source: ITU-T SG 13

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Medium-term - Convergence on MPLS Core

MPLS NETWORK

ATMNetworks

Frame Relay

Networks

Frame Relay

Networks

IWF EthernetNetworks

EthernetNetworks

ATM Networks

Label Switching Router (LSR) Label Switched Path (LSP)

IWF IWF

IWF

IWFIWF

• Requires well defined interworking mechanism for all services• Transfer plane functions• Control plane functions• Management plane functions

• Requires well defined interworking mechanism for all services• Transfer plane functions• Control plane functions• Management plane functions

Source: ITU-T SG 13

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Inter-Network Resources

• Successful solutions have to combine End to end operation control Inter-domain resource negotiation

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Inter-network Negotiation

Alternative approaches include Requiring each network to support a limited range of QoS/network

services (inflexible and prescriptive) Network by network negotiation (but how to ensure required service

is available?)

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Ongoing Work

• International and national work is need to introduce interoperable next generation networks. Areas requiring work include Architecture and Protocols End to end QoS Service platforms Network management Lawful interception Security

• This work is being carried out in the IETF, the ITU and regional telco standards bodies such as ETSI

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Ongoing Work

• Given the proposed use of Internet Protocols, much current IETF work is directly relevant

• Work is needed to define inter-network (inter-domain) interconnection and operation

• The following slides summarise some of the current work at the international level. Other bodies working on NGN include fora and consortia such as the Multi-service Switching Forum and the MPLS Forum.

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International Work - IETF

• RTP (Real Time Protocol) Carries VoIP audio media Used by H.323, SIP, Megaco/H.248, others.

• SDP (Session Description Protocol) Describes multimedia sessions Used widely as well, see above.

• SIP (Session Initiation Protocol) Rendezvous protocol, discovery and session

management Commonly used as VoIP signalling protocol Associated with MMUSIC, SIP, SIPPING, SIMPLE

WGs

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• ENUM (E.164 Number Mapping) Transforms E.164 telephone numbers into URLs used for SIP, HTTP, SMTP, etc. Interim operation plan for e164.arpa is a collaboration

between IETF (Internet Architecture Board) and ITU-T (Study Group-2)

• SIP-T (Interworking SIP & ISUP) Defines encapsulation of ISUP in SIP and mapping between

SIP & ISUP fields SIP-T architecture is approved document SIP-ISUP mapping is close to approval Current ITU-T SG 11 work on application for NGN-legacy

network interworking

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• Interworking SIP & H.323 Requirements almost complete

• Security and VoIP TLS, Digest, S/MIME, IPSEC IETF protocols from

Security Area Used to secure SIP and SDP SRTP SIP Privacy/Identity work MIDCOM (firewall control)

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• Media Gateway Control Megaco MGCP

• Transports for VoIP SCTP

• Signalling transport New work begun on DCCP, unreliable protocol

with congestion control properties

• Service development CPL (Call Processing Language) SIP CGI (Applying HTTP service creation to SIP) New work underway on Speech Services Control

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• Accounting and Management DIAMETER

• AAA protocol

• Signalling Compression Robust Header Compression

• Specifications for IP/UDP/RTP headers and the SIP/SDP messages to be compressed, especially for wireless VoIP uses.

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International Work - ITU

• ITU-T Study Group 13 Overall responsibility for IP work Recommendations/areas of work include

• Rec. Y.1541: Quantifying User QoS Needs in IP Terms• Rec. Y.1221: Traffic and Congestion Control in IP Based

Networks

Leading ITU’s “NGN 2004” project

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• ITU-T Study Group 11 Responsible for signalling and interworking. Current work

includes• Interactions between IN and IP-based networks• IP-related signalling protocols• Bearer (ATM, IP) Independent Call Control (BICC)• Signalling transport over IP• Use of SIP for user access and network-to-network interfacing

Has just initiated new projects on signalling control• between session control functions (across networks),• between session, resource and bearer control, and • between session control and user profile management.

Other new work on control architecture and signalling requirements about to commence.

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• ITU-T Study Group 12 Lead group for end-to-end transmission

performance. Areas of work include• Transm. Req’ts for IP gateways and terminals• E-Model (model for speech quality incl.VoIP)• Transm. Plan. for VB, Data and Multimedia• Transm. of multiple interconnected networks• Voiceband services via IP networks• Multimedia QOS and perf. requirements• Effects of multiple IP domains on VoIP• QOS coordination in the ITU (as Lead SG)• In-service non-intrusive assessment of VoIP

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• ITU-T Study Group 16 Lead group for multimedia and convergence. Work

includes• Voice Coding• Video Coding• Multimedia Signalling; including Data Conferencing,

Modems, Facsimile, Call control and conference control and Media gateway control (H.248)

• Security• Multimedia Architecture (H.323)• Mobility• Emergency Telecommunication Services

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International Work - ETSI

• Considerable NGN work in all areas, including TIPHON (VoIP and Multimedia) SPAN (Signalling and interworking) Security and Coding work

• Co-ordinated by ETSI Board “NGN Implementation Group”

• Major input to 3GPP IP work

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ACIF NGN Project

• ACIF’s Strategic Plan in early 2001 identified need to work on “Next Generation Networks”

• Meetings with ACA, ACCC and SPAN confirmed they had a similar interest.

• ACCC sponsored an initial consultancy in second half of 2001 “to raise issues”

• ACIF held an NGN seminar in May 2002 to scope the issues

• Attendees proposed a continuing industry “conversation” on NGN matters.

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ACIF NGN Project

• The ACIF Board agreed to support an ACIF NGN Project, working through the ACIF NGN Framework Options Group (“NGN FOG”).

• The aim of the ACIF NGN Project is to help all involved discuss issues that cross current boundaries, including Internet/telco divisions Regulatory issues (ACA and ACCC) Industry issues (including self-regulation

requirements) Policy issues

• An early agreement was that user requirements must be the main driver of this work.

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NGN FOG Work

• The main task of the NGN FOG is to assist understanding of the transition to next generation network equipment. The NGN FOG work involves consideration of issues including Technical standards End-user issues End-to-end services Interconnection across networks Regulatory issues (both self-regulation and

government regulation

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You are invited….

……to help with this work

Details at

www.acif.org.au/ngn

1 converging telco and internet standards peter darling manager, international & ngn, australian...

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