Transcript Presentation 3

PSTN renewal
Next Generation Access and Network
IMS and fixed-mobile convergence
Jean Craveur
France Telecom
Networks, Carriers & IT
January 2006
Summary
Context
The PSTN issue
Next Generation Access and Network
IMS a tool fot Fixed-Mobile convergence
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Context
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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
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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
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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
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Multiservice Multi-VC Architecture
Internet
Service
Plat-forms
VC Best Effort
Network
Termination
BAS
Video Service
Plat-form
Audio Visual
Service Nodes
STB
VoD Server
VC QoS
MAG
Digital TV
Network Access
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The PSTN renewal issue
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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
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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
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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
more
 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
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Possible scenarios
Migration towards VoIP gives room in 3G circuit
switches
 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
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Which technology for conversational
services?
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
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Next Generation Access and
Network
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Our vision: One IT & Network
Shared Information System
Service Platforms
Control Layer
IP / MPLS Backbone
Gigabit Ethernet
Transmission
Customer
Access Network
Aggregation
Core/Backbone networks
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Evolution in access networks
Copper
Optical
Fibre
Aggregation
node
 New Fixed and Mobile technologies enable increased bit rates,
better cost efficiency, better quality and convergent services
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Broadband everywhere
Rate (bps)
Wireless
Local Loop
1 to 60 Mbps
VDSL
20 to 50 Mbps
Wifi
11 to 54 Mbps
ADSL 2
10 to 25 Mbps
HSDPA
14 Mbps
ADSL
0.5 to 8 Mbps
Cable modem
1 to 4 Mbps
ISDN
64-128 kbps
1 to 3 Mbps
EDGE
200 kbps
PSTN
56 kbps
GPRS
UMTS
In mobility
Fixed usage
50 kbps
2000
2003
2005
2007
Source: Idate
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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
services
 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
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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
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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)
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Evolution in aggregation and backbone
networks
Aggregation
Universal
Access Node
(e.g. enhanced
DSLAM)
 Security, end-to-end
Quality of Service
Backbone
 IP V6
 SIP
Giga Ethernet
Use for UMTS
access
 MPLS
 Gigarouters
Fibre bit rate increased with DWDM
Automatically Switched Optical Network (ASON)
Multi Service Provisioning Platform (MSPP)
Transmission
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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
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NGN and Triple play offers
Internet L2VPN
Unicast & multicast
Routing
PFS
PFS
RB
Internet BAS
IP Backbone
RBCI
CI
VLAN Internet
VLAN BC-TV
VLAN VoD
VLAN Videophony
VLAN Management
Service platform(s)
PoP IP/MPLSrouteurs=« NM »
MDF IP/MPLS Router
BC-TV
Business WAN
backbone (ATM,
MPLS, SDH)
DSLAM
VoD Server
VoD Server
Videophony
Servers
Wholesale
Videophony
Servers
ISP
Business
Customer LAN
Optical NTU
IP/MPLS
MDF
Copper NTU
Modem
CE
STB
MDF
?
DVD
MDF
Business
Customer LAN
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IMS and fixed-mobile convergence
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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
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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
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NGN/IMS make possible convergent services
Application
User information
Network and service control information
Service Platforms
Roaming and
mobility
HSS
Control
Common control layer
Transport
SIP
protocol
DSLAM
Aggregation
IP/MPLS Backbone
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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 ?
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Main issues for VoIP/NGN networks (2)
Transport /control separation
 Makes possible important voice and service control
centralization
 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 ?
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