In an environment that is using RSVP-TE signaling to establish LSPs, the MPLS Topology Server matches various attributes (LocalAddress, FromIP, ToIP) that are associated with the RsvpProtocolEndpoints that are discovered on different PE and P devices, and creates an RsvpSession instance for each complementary match.
An RsvpSession is ConnectedTo two RsvpProtocolEndpoints, where one RsvpProtocolEndpoint is HostedBy one PE or P device, and the second is HostedBy a peering PE or P device. The RsvpSession provides a bidirectional signaling path through which the two peering devices exchange MPLS label information for the purpose of constructing, maintaining, or deleting TE LSPs or subLSPs.
Here are some other relationships that are computed for RsvpSession:
RsvpSession relationship Endpoint1
Points from an RsvpSession to the RsvpProtocolEndpoint that represents the source RSVP-TE speaker for the session.
RsvpSession relationship Endpoint2
Points from an RsvpSession to the RsvpProtocolEndpoint that represents the destination RSVP-TE speaker for the session.
RsvpSession relationship Source
Same as Endpoint1.
RsvpSession relationship Destination
Same as Endpoint2.
RsvpSession relationship Underlying
Points from an RsvpSession to the TE LSP or subLSP that is associated with the session.