The Renegotiable Variable Bit Rate Service: characterisation and prototyping

The tra c generated by multimedia applications presents a high degree of burstiness that can hardly be described by a static set of tra c parameters. We present a dynamic QoS negotiation scheme applied to a prototype application that provides temporized data transfer. The dynamic and e cient usage of the resources can be reached with the introduction of the renegotiable variable bit rate (RVBR) service, which is based on the renegotiation of the tra c speci cation. We describe and discuss the RVBR service and how it applies to resource reservation for Internet tra c with RSVP. We propose an architecture design that we evaluate by accomplishing a prototype implementation, whose performance is measured with temporized le transfer using real MPEG2 video traces. The results we obtained indicate that renegotiation is an e cient mechanism for accommodating tra c uctuations over the burst timescale and that the RVBR service can be easily implemented in real applications, using available technology.