Design of a two-pass RSVP setup mechanism for integrated services

RSVP bandwidth reservation mechanism using one-pass with advertising may encounter killer reservation problems [12], when more than two reservation requests are merged from different receivers. In this paper, we present a two-pass with advertising (TPWA) mechanism to inherently avoid the killer reservation problems. TPWA requests pre-engaged bandwidth at the first pass before actually reserving bandwidth at the second pass. The pre-engaged bandwidth is a tagged bandwidth which may be used to deliver non-QoS traffic using the resources that QoS traffic map later request for reservation. Hence, the percentage of pre-engaged bandwidth to be allocated at a router under a receiver's request may significantly affect the transmission quality of QoS traffic. We develop algorithms for RSVP modules at a router to dynamically convert the free bandwidth to the pre-engaged bandwidth and finally to the reserved bandwidth.