Abstract

There is general agreement that a Next Generation Network (NGN) will have, at its core, a packet-switched architecture. This agreement was underscored at the ITU-T Workshop on Next Generation Networks held in July 2003, [1]. There is general agreement, also emphasized in this Workshop, that legacy services shall be supported for many years to come and, further, that the evolution of the Network to its “converged” form shall provide quality of service capabilities that would make the NGN transparent to these legacy services. These legacy services include, but are not limited to, constant-bit-rate (CBR) services whereby legacy end-user equipment such as E1/T1 multiplexers and integrated access devices, Private Branch Exchange (PBX) equipment, and ISDN terminals, continue to exist and demand service at a quality level provided in today’s (circuit-switched) Public Switched Telephone Network (PSTN).

© 2005 Optical Society of America