IETF RFC 4974 PDF

In certain networking topologies, it may be advantageous to maintain associations between endpoints and key transit points to support an instance of a service. Such associations are known as Calls.

A Call does not provide the actual connectivity for transmitting user traffic, but only builds a relationship by which subsequent Connections may be made. In Generalized MPLS (GMPLS) such Connections are known as Label Switched Paths (LSPs).

This document specifies how GMPLS Resource Reservation Protocol - Traffic Engineering (RSVP-TE) signaling may be used and extended to support Calls. These mechanisms provide full and logical Call/Connection separation.

The mechanisms proposed in this document are applicable to any environment (including multi-area), and for any type of interface: packet, layer-2, time-division multiplexed, lambda, or fiber switching.