What are the latency specifications for BT's 21CN network?
BT is seeking to minimise the latency of information within its network. Services that are latency-critical will continue to be provided on an SDH TDM infrastructure, where latency will be minimal (latency is in the main dominated by fibre route km, which is approx 0.005ms per km). Other services will be emulated over an MPLS core network, and will experience an additional packetisation delay of the order of 5ms. Voice services will be carried as VoIP and we are targeting a delay of less than 35ms end-to-end for the segment of the call carried on BT"s network, assuming a single TDM:IP conversion at each end. In addition, there will be a speed of light delay due to distance, at worst at 8ms for calls within the UK.
Will the existing POC interconnection continue?
Initially, existing POCs will be retained to the existing standards. We will continue to support existing methods of voice interconnect for a number of years to enable our customers to move to IP Interconnect arrangements in a planned way that suits their own network development strategy.
Will existing service interconnect be maintained or emulated?
BT will be offering UK ISUP TDM interconnect at the Metro Nodes. IP interconnects for PSTN/ISDN will be defined by the NICC.
Will there be inter-operator interconnects to the 21CN MPLS core?
There are no plans to have inter-operator interconnects to the 21CN MPLS core. The MPLS core is internal to 21CN and provides connectivity between Metro Nodes. Next generation IP-based inter-operator interconnects are being defined under the auspices of the Consult21 Industry Working Group and within the NICC. These will be defined for each service that will be interconnected. MPLS may form part of the technical specification of the interface but we do not envisage MPLS interconnects being defined independently of the services supported.
Will Carrier Pre-Selection (CPS) be migrated to 21CN?
BT is planning seamless migration to 21CN for CPS and current features and functionality will be maintained as far as possible so that BT continues to meet its obligations.
