NGN an architecture for 21st century networks?

1
NGN an architecture for 21st century networks?

• ITU-T NGN Workshop (Geneva, 9-10 July 2003)
• Keynote session
• Patrice Collet (France Telecom, Director, Network
  Strategy and Architecture)

2
FT global network evolution context

• A very competitive environment
• Keeping network costs as low as possible
• Faster return on investment is needed
• A strong pressure to tariff decrease
• PSTN traffic slowly growing
• Shared now between several competitors
• A steady data traffic demand growth resulting
  from Internet traffic demand
• Started with dial up access
• Increased with broadband access offers

3
Major network evolution trends (1)

• A large ADSL deployment
• End 2002
• 2000 mdf (out of 12 000) equipped with DSL
  serving 21 millions lines
• 1.4 million users connected
• A rapid growth more than 2 millions users end
  June 2003
• Packet backbones deployment
• Expansion of ATM network to collect traffic from
  DSLAMs
• More than 400 ATM cross connects (starting from
  80 in 1998)
• An IP backbone deployed serving around 60 PoP in
  30 towns
• With ADSL a new type of mass market access
  network is being built
• To meet an actual and ready to pay demand the
  second time in telecom history after telephone
  service

4
Major network evolution trends (2)

• Stable telephone network
• Reduced number of core switches from 900 to
  less than 600 end 2002
• Decrease of the number of transit exchanges
• To face evolution of interconnection traffic
  scheme
• And reduce network costs (energy, m², taxes)
• A limited number of new facilities to be
  implemented (in general IN based)
• Reduction of software releases to be deployed
• A good quality of service
• No short term obsolescence of switching
  equipments
• But a part of local exchanges are now roughly 20
  years old
• Renewal imagined starting in the second part of
  the decade
• Which technology for the future telephone
  service?
• TDM network renewal strategy

5
Access network perspective

• Through its increasing bandwidth, xDSL gives the
  potential of new services
• New multimedia services integrating voice, data
  video could be provided,
• These services are now appearing on the Internet
  (videophony videoconference, streaming of video
  clips, Web TV, ), but with uncontrolled QoS
• xDSL opens the door to residential and SME voice
  services migration to packet networks
• xDSL deployment shapes the future access network
  architecture
• ADSL, ADSL2, SDSL, VDSL interfaces provided by
  the same DSLAM
• End user fiber connection to DSLAM with ATM
  traffic concentration
• Integration of video functions
• Digital TV program broadcasting and channel
  zapping
• In some DSLAM implementations POTS connection are
  or will be provided
• DSLAMs as the future universal customer
  connecting unit?

6
NGN as the 21st century network architecture?

• What provides NGN concept ?
• A unified packet transport layer for all types of
  services
• A session based control architecture
• For person to person voice or video services over
  a packet infrastructure
• FT expectations from NGN
• Be the support of new multimedia services
  combining voice data and video
• To generate new revenue streams
• In addition be the future infrastructure of
  telephony services
• Shared with multimedia services
• To face the need for renewing PSTN
  infrastructure (when obsolete)
• While securing voice revenue stream
• Be able to combine Internet services and more
  traditional communication services
• Interest for NGN focussed on access systems

7
Some requirements for NGN implementation

• Need for interoperability between equipment
  providers
• Commonly agreed functional and organic
  architectures needed
• A set of standardized interfaces and protocols to
  be agreed upon
• Ability to serve several kinds of access network
• Fixed copper, fiber, wireless..
• Mobile
• An open services architecture
• Standard interfaces open to third party service
  providers
• Allowing for Interaction between Internet access
  services and other multimedia services
• Probably more a question of role of actors than a
  technical issue
• An architecture based on UMTS (Release 5/6)
  architecture principles
• Including some mobility features at the fixed
  access user nomadism
• Providing minimum service continuity between
  fixed and mobile access through VHE

8
Some requirements for NGN implementation (2)

• Need for QoS differentiation
• Services like voice, video, need QoS control
  mechanisms
• Especially at the access level
• Limited bitrate access shared between several
  services
• upstream ADSL channel for example
• Need for bandwidth allocation mechanisms
• A set of management functions shared between
  different services
• Self-provisioning, usage metering for billing,
  QoS monitoring, statistics..
• A common technology for transport layer
• IP and MPLS seem the good candidate for such a
  layer
• Large world industrial support and good evolution
  speed
• ATM for bandwidth sharing on copper to provide
  QoS to voice and video services
• Significant efforts of standardisation/ selection
  of relevant standards work still to be done

9
Architecture standardization needs
Open interfaces
Management
Separated control
Unified transport
10
Conclusion

• There is an opportunity window for NGN
  architecture implementation
• Obsolescence of TDM systems started to be
  deployed in the early 80s
• Two key questions
• True multimedia capability of this architecture
• QoS benefits provided by NGN compared with
  ISP-like architecture
• Some challenges
• Keep an integrated architecture open enough
• To make it capable to quickly and easily evolve
• Achieve the necessary industry consensus
• To meet the interoperability requirements