Transcript 21CN PSTN – Separating speech and control

Introduction to 21CN Resilience
Tim Hubbard
Head of 21CN Solutions Strategy
Proposed topics for discussion
Introducing the new architecture for PSTN
21CN Resilience and security
21CN – Three key objectives
• Empower the end user with
control, choice and flexibility like
never before including
communications from anywhere to
any device
• Offer exciting new services
for end user faster than before
• Reduce costs and grow cash cost
savings - expected to amount to
£1 billion per annum by 2008/9
Speed to
market
End user
experience &
empowerment
Cost
transformation
21CN - evolution
PSTN
PSTN
Copper
DPCN
KiloStream
ATM
A single network that’s physically
simpler and more reliable than
our existing, complex
infrastructure could ever be
Up to 50 per cent fewer
components in terms of
switches, hubs, routers and
suchlike.
DSL
ASDH
IP
Fibre
CWSS
SDH - MSH
SDH - mesh
DWSS
End
User
PDH
~5k
nodes
~2k
nodes
~1k
nodes
~400
nodes
~100
nodes
Multi-service access
Converged core
Class 5
Call Server
Copper
We will be able to deliver the
next generation of converged
services faster, more efficiently
and more cost-effectively than
ever before.
Today
~15
nodes
WWW
DSL
Fibre &
Copper
IP-MPLS-WDM
Agg Box
Content
ISP
Wireless
End
User
~5.5k
sites
~100
sites
Current thinking. No implementation assurances
21CN
Traditional PSTN architecture
• Dedicated hierarchical network of concentrators,
local, trunk and tandem exchanges, with fixed
relationship between all
• Dedicated network of trunks and circuits for
voice traffic, each call has its own circuit
• Call control traffic and voice traffic directly
connected together
• Call control and routing carried out by all
switches in the network
Complex
Inflexible
Restrictive
21CN PSTN – Separating speech and control
MSAN: delivers either copper
based or fibre based services
21CN
to end customers
Metro/Core
MSAN
MSAN: Converts analogue
PSTN speech into VoIP
MSAN: Copper version has
“combi card” functioning as
DSLAM for broadband and
concentrator for PSTN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
VLAN: Dedicated bandwidth
across Ethernet backhaul
network (MSAN to Metro
Node) for carrying PSTN
signalling traffic, PSTN speech
traffic, broadband traffic, etc
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
Call Server: Carries out call
control, processing dialled
digits, setting up and tearing
down telephone calls, etc
Metro/Core
Directory: Holds all PSTN
numbers, whether they are on
21CN, legacy PSTN, other CP
network.
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
Metro/Core
21CN
MSAN
Signalling Firewalls: Gateway
for signalling traffic to/from
21CN call server to set up
MSAN
telephone calls to/from 21CN to
legacy PSTN and other CP
networks
PSTN
Session Border Controllers:
OCP
Gateway for telephone
calls
between 21CN and legacy
PSTN/other CP networks
21CN PSTN – Separating speech and control
- 21CN to 21CN call
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
- 21CN to 21CN call
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
- 21CN to 21CN call
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
- 21CN to 21CN call
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
- 21CN to OCP/PSTN
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
- 21CN to OCP/PSTN
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN PSTN – Separating speech and control
- 21CN to OCP/PSTN
Metro/Core
21CN
MSAN
PSTN
OCP
MSAN
21CN Resilience
Service
Ethernet
MPLS
SDH/WDM
MSAN
D-WDM
Metro
Core
• Physical: Building, ducts, equipment, fibre, etc
• Logical:
Optical and packet protocols
De-couple each “layer”
Recover at the lowest level possible
Maintain service availability across 21CN
21CN Resilient PSTN
• Voice
• Controlled by call server
in Metro/Core Nodes
Core
Node
• Each MSAN has at least
two routes to its primary
call server
Core
Node
• Each MSAN will have a
primary and secondary
call server
Metro
Node
Tier 1
MSAN
FMSAN
CMSAN
21CN Resilient PSTN
• Voice
• Controlled by call server
in Metro/Core Nodes
Core
Node
• Each MSAN has at least
two routes to its primary
call server
Core
Node
• Each MSAN will have a
primary and secondary
call server
Metro
Node
Tier 1
MSAN
FMSAN
CMSAN
21CN Resilient PSTN
• Voice
• Controlled by call server
in Metro/Core Nodes
Core
Node
• Each MSAN has at least
two routes to its primary
call server
Core
Node
• Each MSAN will have a
primary and secondary
call server
Metro
Node
Tier 1
MSAN
FMSAN
CMSAN
X
21CN Resilient PSTN
• Voice
• Controlled by call server
in Metro/Core Nodes
Core
Node
• Each MSAN has at least
two routes to its primary
call server
Core
Node
• Each MSAN will have a
primary and secondary
call server
Metro
Node
Tier 1
MSAN
FMSAN
CMSAN
X
21CN Reliability, continuity and resilience
• 21CN is a private IP network, NOT the Internet
• 21CN separates network and services for increased resilience
and faster service delivery
• 21CN is engineered with high availability and resilience
• 21CN Assurance agreed with Central Sponsor for Information
Assurance
Webcall update
18 April
Product retirements
24 April
21CN overview
2 May
Migration process
22 May
CPE compatibility testing programme
31 May
Switched-on communications campaign
20 June
Pathfinder programme overview
9 July
Preparing for 21CN migration
26 July
Broadband migration programme
2 August
21CN resilience and security
27 Sept tbc
Migration portal overview
Industry invited to suggest topics of interest …further webcalls will be scheduled
for the rest of 2007
Sources of further information
• Information and support for communication providers on
the 21CN programme:
http://www.btwholesale.com/consult21
• The independent public information website covering
the process of migration:
http://www.switchedonuk.org
• For general information about BT’s 21CN programme
go to:
http://www.btplc.com/21CN/
Questions

Answers