Converging Telco and Internet Standards Peter Darling Manager, International

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Converging Telco and Internet StandardsPeter
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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• 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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• 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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Carrier Networks are not homogeneous

• 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

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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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..
Backbone transport

• 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

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To provide QoS..
Bearer Control
Backbone transport

• 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

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To provide QoS..
Call Control
Bearer Control
Backbone transport

• 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)

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To provide QoS..
Service/application
Call Control
Bearer Control
Backbone transport

• 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

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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

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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 implementationsthe subject of
  current international work

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Todays Network Architectures
IP/MPLS Networks
Radio Access Networks
Ethernet Networks
Source ITU-T SG 13

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

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Near Term Evolution
SS7 Network
Q X series Rec.
Rec. Q.931
Frame Relay Networks
Rec. Q.700 series
Rec. I.580
Rec. Q.2931, PNNI
FR OSF NM
Rec. I.555
Rec. I.580
PSTN/ISDN OSF NM, M series Rec.
IETF RFCs
ATM Networks
IP-based Networks
Rec. Y.1310
ATM OSF NM, M series Rec.
SNMP based

• 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

• Against
• Lack of service transparency between IP based
  services and ATM/PSTN services

OSF Operating Support Function
Source ITU-T SG 13
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Medium-term - Convergence on MPLS Core
ATM Networks
Frame Relay Networks
MPLS NETWORK
Frame Relay Networks
Ethernet Networks
Ethernet Networks
ATM Networks
Label Switching Router (LSR)
Label Switched Path (LSP)

• 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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International Work - IETF

• 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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International Work - IETF

• 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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International Work - IETF

• 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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International Work - IETF

• 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 ITUs NGN 2004 project

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International Work - ITU

• 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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International Work - ITU

• ITU-T Study Group 12
• Lead group for end-to-end transmission
  performance. Areas of work include
• Transm. Reqts 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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International Work - ITU

• 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

• ACIFs 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