Our NGN uses internet protocol (IP) switching and dense wave-division multiplexing (DWDM) transmission to provide voice and data capacity for millions of concurrent end users, at a lower cost than legacy networks based on time-division multiplexing (TDM) switches.
Packet switching enables support for voice and data services over one switching and transmission infrastructure, so operating costs are lower for us than for operators with multiple networks. From the end user’s perspective, our NGN behaves in the same way as the PSTN, so for example when a line is unbundled, analogue handsets can be re-used, call features work in the same way and the phone bill has a familiar look and feel.
Our NGN core and backhaul network use Ethernet. Voice switching is voice over IP (VoIP). VoIP and data traffic are conveyed via separate virtual local area networks (VLANs) so that time-critical packets containing voice are unaffected by packets containing data. Multi-service access nodes (MSAN) are deployed in the exchanges to support analogue telephony and broadband internet. Gateways between our NGN and BT’s network provide access to the PSTN and public internet.