TURE TO 2030: TELECOM, LAND TRANSPORT, WATER AND ELECTRICITY - ISBN 92-64-02398-4 © OECD 2006 2. TELECOMS INFRASTRUCTURE TO 2030 Figure 2.10. 21 CN's simplified core Legend ATM: Asynchronous digital hierarchy Copper ASDH: Asynchronous transfer mode CWSS: Copper wideband serving section KStream DPCN: Digital private circuit network Inter-node DSL: Digital subscriber line transmission DWSS: Digital wideband serving section KStream: Kilostream provided by SDH/PDH MSH: Marconi synchronous hierarchy platforms MPLS: Multi-label protocol switching Fibre PSTN: Public switched telephone network DWSS Mesh of SDH MSH SDH PDH: Plesiochronous digital hierarchy SDH: Synchronous digital hierarchy A simplified network (21CN) nodes nodes nodes nodes nodes nodes PSTN Migration Converged Core An OECD operator's current network Copper Class 5 Call server infrastructure Fibre and IP-MPLS-WDM FIBRE TRUNK Copper Aggregation Migrate Content nodes nodes For the ordinary consumer, BT claims its 21CN will deliver more choice, control and accessibility, as well as increased flexibility, reliability and security. For private networks for large corporate customers, the "route distinguishers" using packet header information segregate the customers' Virtual Private Network (VPN) traffic. Existing VPNs become micro-versions of the whole 21CN network architecture, with any-to-any connectivity and traffic prioritisation. 21 CN also offers a simpler service management model, for greater efficiency in dealing with customers. By 2009, "broadband dialtone" will be available to most BT customers in the United Kingdom. Customers will be able to switch lines to broadband use themselves with no physical work required at the exchange. Long distance fibre - the cost enabler The major change in the cost of infrastructure has been in long distance transmission, be it national, international, terrestrial or sub-sea. The technology of the "global backbone" has reduced in price by several orders of magnitude over the past decade as bandwidth per link has increas