RSVP is a resource reservation setup protocol designed for quality integrated services on Internet. RSVP is used by a host to request specific qualities of service from the network for particular application data streams or flows. RSVP is also used by routers to deliver quality-of-service (QoS) requests to all nodes along the path(s) of the flows and to establish and maintain state to provide the requested service. RSVP requests will generally result in resources being reserved in each node along the data path.

RSVP requests resources in only one direction. Therefore, RSVP treats a sender as logically distinct from a receiver, although the same application process may act as both a sender and a receiver at the same time. RSVP operates on top of IPv4 or IPv6, occupying the place of a transport protocol in the protocol stack. However, RSVP does not transport application data but is rather an Internet control protocol, like ICMP, IGMP, or routing protocols. Like the implementations of routing and management protocols, an implementation of RSVP will typically execute in the background, not in the data forwarding path.

RSVP is not a routing protocol by itsself; RSVP is designed to operate with current and future unicast and multicast routing protocols. An RSVP process consults the local routing database(s) to obtain routes. In the multicast case, for example, a host sends IGMP messages to join a multicast group and then sends RSVP messages to reserve resources along the delivery path(s) of that group. Routing protocols determine where packets get forwarded; RSVP is only concerned with the QoS of those packets that are forwarded in accordance with routing.

Protocol Structure

• Command -- two commands are: Request: A request for the responding system to send all or part of its routing table. Response: A message containing all or part of the sender’s routing table.
• Version -- The current version of RIPng is version 1.
• Route table entry -- Each route table entry contains a destination prefix, the number of significant bits in the prefix and the cost of reaching that destination.

Related Terms: IP, IPv6, IGP, EGP, RIP, UDP, TCP

Sponsor Source: RIPng is defined by IETF (http://www.ietf.org) RFC2080.

Reference: http://www.javvin.com/protocol/rfc2080.pdf: RIPng for IPv6