PSTN renewal Next Generation Access and Network IMS and by zcy88772


									PSTN renewal
Next Generation Access and Network
IMS and fixed-mobile convergence
Jean Craveur
France Telecom
Networks, Carriers & IT

January 2006


The PSTN issue

Next Generation Access and Network

IMS a tool fot Fixed-Mobile convergence


IP: the basic structure of new networks
 Capability of IP to transport almost all services
     VoIP, multimedia…
     But need to find means to guarantee QoS and security

 A huge traffic increase
     Large IP networks have been deployed:
         Economic interest to be shared by several services

 This transport network can be used to transport service
  and network control information
     Flexibility to build new services: any device connected can act as
      a control point
     But major security problems remain to be solved : any device
      connected can interact with network control and management

 Specialized networks can now migrate towards these
  shared IP networks

An increasing access bit rate
xDSL over copper lines
    Important DSL coverage announced in many countries
    With bit rates depending on copper line length
       In France more than 95% of the lines are 512/128 kbit/s capable

 Allowing multi-service access
    Coexistence of several services on the same access
       Data, video, voice (fixed or mobile)…
    Based on IP connectivity

Access traffic increase is a general trend
    ADSL2+, then VDSL, VDSL2, and FTTx

The copper line is no longer a bottleneck to service evolution

Technical access evolution

DSLAM evolutions
    From ATM based core architecture to Ethernet
    Implementation of IP layer 3 functions (CoS)
    Optical accesses
       Point to Point or PON architecture
    Telephony analog interface including VoIP gateway function

Connection to DSLAM a move towards Ethernet
    To face economically increasing bandwidth needs (vidéo)
    Consistent with structural DSLAMs core evolution of the
       this is an important evolution to be well managed in aggregation networks

DSLAM becomes the Multi-service Connecting Unit based
 on Ethernet
Multiservice Multi-VC Architecture


                     VC Best Effort                                     Service
       Network                                                          Plat-forms

                                                                        Video Service
                                                        Audio Visual
                                                       Service Nodes

 STB            VC QoS                                                 VoD Server


                                        Digital TV
                                      Network Access

The PSTN renewal issue

Voice traffic and technology evolution

  Rapid modification in traffic volumes
      PSTN traffic decreases significantly:
          Originating PSTN voice traffic is decreasing
               Traffic transferred to mobiles and VoIP, but PSTN traffic decrease slowdown in 2005 due to
                unlimited offers over PSTN
          Internet switched access is decreasing (-46% 2005/ 2003)
               Traffic transferred to Broadband access
      Mobile traffic mobile is increasing (+9.3% March 2005/March 2004)
      VoIP traffic is increasing (end 2005 around 10% of the Fixed traffic, 13% for
       Mass Market)
      The overall voice traffic is increasing (fixed + mobile) (around + 7%, +5,2% for
       Fixed traffic including VoIP)

  A strong technological mutation
      Fast deployment of broadband DSL access combined with LLU fast growth
          Appearance of significant competitive VoIP offers
          Accelerating voice PSTN originated traffic decrease
      FT VoIP service started combined with Internet access
          As a second line service
      First line services with full unbundling take off
      Solutions for fixed access used by GSM networks
          UMA,
      Wifi implementation in mobile terminals
   Some uncertainties remain
The content of Voice Services is uncertain
    Present VoIP offers can modify significatively the vocal usage and
     therefore the PSTN use and economy
    Present VoIP offers are in general
       Limited in terms of services
       With QoS still lower than PSTN (service availability)
    Enhanced voice offers with native IP terminals are going to happen
     with for instance videophony
    Will a place remain for service on analog lines ?

 A non yet stabilized technical context
    Fixed – Mobile convergence perspectives with the NGN/IMS

Impact on PSTN
Traffic decrease on PSTN
    Evolution managed by reducing the number of switches (transit
     and local)
A part of FT TDM switches reaching the end of their life span
    Second generation of TDM switches (2G) installed on early 80s
    More than half of 2G subscribers switches are 20 years old or
    2G Subscribers units design : second half of the 70s
       More than 10 millions subscriber equipments
       Thousands of subscribers units
    Traffic decrease (if confirmed) may reduces the need for PSTN
     equipment replacement
       VoIP infrastructure is an alternative to PSTN
Need for evolving “PSTN service” to “enhanced services”
    Convergent fixed mobile offers
    More sophisticated voice offers, multimedia offers…
    A new generation VoIP infrastructure needed
Possible scenarios
Migration towards VoIP gives room in 3G circuit
   Two possible solutions (which can be combined)
      Transfer of analog lines to 3G switches to remove 2G switches
      Migration of analog lines on POTs accesses in DSLAMs
   In this 2nd case necessity
      Not to have major functional service regression
      To have a transparent migration concerning all the phone
       equipments at subscriber’s premises
      To ensure the same availability and quality of service as before

DSLAM becomes the central element for future
 voice offers
   For VoIP (use of ADSL)
   To connect remaining PSTN lines
 Which technology for conversational
Main requirements
   Get an architecture open to future multimedia services
      Base the architecture on IP connectivity
      Provide a control architecture able to offer other services
          External application servers capability
          Nomadism capability embedded
   Get a robust architecture against voice future uncertainty
      A unique way to transfer voice in the core network
          VoIP seems to be the solution
      A common access network for all conversational traffic
          DSLAM as a universal connecting unit
   Take benefit from being an integrated operator
      Share technologies between fixed and mobile
      Take benefit from IMS definition from the mobile side

Next Generation Access and

 Our vision: One IT & Network

                                    Shared Information System

                                       Service Platforms

                                          Control Layer

                 Gigabit Ethernet                             IP / MPLS Backbone


                  Aggregation                                   Core/Backbone networks
Access Network

  Evolution in access networks




 New Fixed and Mobile technologies enable increased bit rates,
better cost efficiency, better quality and convergent services 16
Broadband everywhere

Rate (bps)

              Wireless                            VDSL
             Local Loop                       20 to 50 Mbps
             1 to 60 Mbps          Wifi
                              11 to 54 Mbps
                                                 ADSL 2
                                              10 to 25 Mbps                   HSDPA
                                                                              14 Mbps
                       0.5 to 8 Mbps

                       Cable modem                             UMTS
                        1 to 4 Mbps                       1 to 3 Mbps

                       ISDN                                    EDGE
                    64-128 kbps
                                                              200 kbps
             56 kbps                                                            In mobility
 50 kbps                                                                        Fixed usage

         2000                          2003                     2005                  2007

                                                                         Source: Idate        17
NG broadband access strategy
Increase service reach with higher bandwidth
    To answer the demand of migration to higher bandwidth
    To expand video services area

Increase DSLAM backhaul bandwidth
    To face a growing number of broadcast video programs
    Evolution from ATM to GE on all DSLAM providing video
       More bandwidth
       Cost reduction

DSLAM as a multi-service connecting unit
    Subscriber fibre connection to DSLAM under trial
    Interest in POTS service provided through DSLAM

  Residential access beyond ADSL
What technology beyond ADSL2+?
      VDSL, VDSL2 in street cabinets up to 20 Mbit/s
      FTTx : more than 20 Mbit/s
      Much more costly than ADSL
      For which new family of services? HD video services?

A number of trials
    VDSL trials on residential market
       To enhance video services coverage
       In Paris suburbs where copper lines are too long
    B-PON experimentations
       Starting with B-PON then evolving to G-PON

FT strategy

Optical entreprise access

 At present,
     Data, leased lines, voice on the same fiber loop
     Optical loop deployment on enterprises
        Nearly 10,000 Large Corporate fibre connections

 GEth MAN infrastructures
     Deployed In 15 of the largest cities
     Access up to 1 Gbit/s for main enterprise sites
     Providing a layer 2 service with QoS guarantee

 B-PON trials conducted
     To serve business locations (10-30 Mbit/s bandwidth need)

    Evolution in aggregation and backbone
                                     Security, end-to-end
                                    Quality of Service
                     Aggregation                          Backbone
                                     IP V6
                                     SIP

Universal       Giga Ethernet                       MPLS
Access Node      Use for UMTS                        Gigarouters
(e.g. enhanced   access

                      Fibre bit rate increased with DWDM
                      Automatically Switched Optical Network (ASON)
                      Multi Service Provisioning Platform (MSPP)


NG Network implementation has started in 2004

    What it is
       NGN (Next Generation Network) allows separation between
        transport and control layers for network and services
    The benefit is cost reduction
       Common IP backbone network, GigaEthernet and ATM aggregation
         networks and enhanced multiservices DSLAMs
    Currently underway
       FT currently operates a VoIP /ToIP and visiophony infrastructure for
         Enterprise and Residential markets in France
       Residential VoIP service opened in 2004
       484,000 VoIP residential customers end of September 2005
    Access to Service Platforms is today through H323 protocol, and is
     planned in 2006 to migrate to Session Initiation Protocol (SIP)

   Complying with new industry standards in view of future
    multimedia services beyond pure voice

NGN and Triple play offers
               Internet L2VPN
               Unicast & multicast                               PFS
               Routing                                                            PFS     Service platform(s)
                                                                                          Internet BAS
                    VLAN Internet
                    VLAN BC-TV
                                                   IP Backbone
                    VLAN VoD                           RBCI
                                                        CI                           PoP IP/MPLSrouteurs=« NM »
                    VLAN Videophony
                    VLAN Management
                                                                                          MDF IP/MPLS Router
                                                                   BC-TV                  DSLAM
  Business WAN
 backbone (ATM,
   MPLS, SDH)                                                    VoD Server

                                      VoD Server
                              Videophony                                                                             Wholesale
                              Servers                                                                                    ISP

                                                                                                  Optical NTU
                                                                                                                      Customer LAN

                                                                                                                Copper NTU

                                MDF                                                                 Customer LAN
IMS and fixed-mobile convergence

Why an IMS based control architecture?
Take benefit of the 3GPP definition work
      System oriented to SIP session control
      Suitable for conversational services
      Include mobility and centralized user data management
      Possible synergies in product development costs (fixed and mobile)

IMS architecture seems to be a good basis for
    Controlling IP phones and Residential GW through SIP protocol
    Controlling DSLAM VoIP gateways (PSTN simulation)
       To serve residual analog lines

Network convergence?
    Restricted to data based applications as long as IMS is not controlling
     mobile voice
    Mobile voice control under study by 3GPP
    Nomadic services in the fixed network

NGN with IMS implementation will start in 2007
  What it is
      IMS (IP Multimedia Subsystem) will provide common control layer for
       fixed and mobile network and services
      Standardized by ITU and ETSI

  The additional benefits
      Further cost reductions
          Control and transport of media flows of any nature and origin,
           including conversational flows
      Enabling the product factory for network-native convergent services (e.g.
       Home Zone phase 2)

  Currently underway
      Specification
      Evaluation of « Application Servers » providing multimedia and
       Fixed/Mobile service continuity to Enterprises

Preparing the common multimedia broadband infrastructure for
fixed and mobile services beyond pure voice                                 26
Application   NGN/IMS make possible convergent services
                        User information                  Network and service control information

                                                           Service Platforms

                                      Roaming and

                      Common control layer



                                                                   IP/MPLS Backbone

 Main issues for VoIP/NGN networks (1)
Define the appropriate IP layer arrangements
    Allowing smooth network management (network life)
    Addressing, security, VPN
    Specific QoS requirements for VoIP?

Define the optimum topology
    Optimum VoIP edge function location, call servers centralisation?
    Impact on aggregation network

Reach the QoS grade of present PSTN
    Reliability, network management and operation functions

Control of mobile voice services through IMS

VoIP/NGN interconnection issue: a way to be defined
    PSTN gateways implementation short term issue
    VoIP interconnection
        To be positionned to peering IP
        Should be the target, which type of service contract between operators ?
Main issues for VoIP/NGN networks (2)
Transport /control separation
    Makes possible important voice and service control
       Ten (s?) call server sites
       To be compared with 500 Local Circuit switches

Voice flows handled upper in the network
    60 à 250 sites de MAG/EDGE

New security requirements
    Risks from Internet
       Concerning the network or the IS which is connected to it
    Centralization makes easier security measures
    Need to logically separate voice ?


To top