The RSVP protocol is used by routers to deliver quality-of-service (QoS) requests to all nodes along data flow path(s) and to establish and maintain state for the requested service. RSVP requests generally result in resource reservations in each node along the data path. RSVP has the following attributes:
Makes resource reservations for unidirectional data flows.
Allows the receiver of a data flow to initiate and maintain the resource reservation used for that flow, as shown in Figure 1.
Maintains a soft state in routers and hosts, providing graceful support for dynamic membership changes and automatic adaptation to routing changes.
Depends upon present and future routing protocols, but is not a routing protocol itself.
Provides several reservation models or styles to fit a variety of applications.
Supports both IPv4 and IPv6 packets that can be sent over RSVP-signaled LSPs.