New services implementation in a B-ISDN testbed by means of attached processors

The definition and development of an architecture oriented to the flexible and fast provisioning of services in a broadband ISDN (B-ISDN) testbed are presented. Some alternatives are analyzed, and it is shown that the flexibility target is reached by a distributed architecture based on specialized processing units, called attached processors (APs), that can be added to the basic asynchronous transfer mode (ATM) switch. APs act as coprocessors of the switching system control and may include spectral signal processing functions with the user plane. The testbed architecture is described, and the switching software platform and specific issues related to the ATM-switch-AP interconnections are addressed, referring to protocol aspects for both control and user planes. To verify the effectiveness of the AP approach by means of experimentation, an audio-conference service has been implemented