Performance analysis of an RSVP-capable router

RSVP is a bandwidth reservation protocol that allows distributed real-time applications such as videoconferencing software to make bandwidth reservati ons over packet-switched networks. Coupled with real-time scheduling mechan isms built into packet routers, the network guarantees to provide the reser ved bandwidth throughout the lifetime of the applications. Although guarant eed services [1] are of great value to both end users and carrier providers , their performance cost, due to additional control and data processing ove rhead, can potentially have a negative impact on the packet throughput and latency of RSVP-capable routers. The goal of this article is to examine the performance cost of RSVP based on measurements from an industrial-strength RSVP implementation on a commercial IP router. The focus is on the detaile d evaluation of the performance implications of various archit ectural deci sions in RSVP. We found that RSVP's control messages do not incur significa nt overhead in terms of processing delay and bandwidth consumption. However , the performance overhead of real-time packet scheduling is noticeable in the presence of a large number of real-time connections. In extreme cases, the performance guarantees of existing real-time connections may not be kep t and some best-effort packets are actually dropped than the available link bandwidth.