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RSVP is an Internet signaling protocol that is used to set up a type of circuit across an IP network, primarily as a means of providing QoS, for real-time traffic such as voice and video. Guaranteed on-time delivery is essential for delay-sensitive information associated with videoconferencing, voice conversations, and virtual reality. This is not easy on TCP/IP networks. As originally designed, the Internet supports only best-effort delivery of data packets. There is little support for QoS, and IP traffic is especially susceptible to variable queuing delays and congestion losses.

IETF's Integrated Services (int-serv) Working Group developed RSVP as part of its effort to define bandwidth reservation techniques for the Internet. By reserving bandwidth, it is possible to provide reasonable levels of QoS. The idea is to identify traffic flows, which are streams of packets (voice, video, file transfers, and so on) going to the same destination IP address and port number. Reservations are negotiated with each network device along a route to a destination. If each device has resources to support the flow, a reserved path is set up.

RSVP (Resource Reservation Protocol) works as a signaling protocol...