Received changes through RFC Editor sync (changed abstract to 'The Path Computation Element (PCE) provides functions of path computation in support of traffic engineering in networks controlled by Multi-Protocol Label Switching (MPLS) and Generalized MPLS (GMPLS).

MPLS and GMPLS networks may be constructed from layered client/server networks. It is advantageous for overall network efficiency to provide end-to-end traffic engineering across multiple network layers. PCE is a candidate solution for such requirements.

Generic requirements for a communication protocol between Path Computation Clients (PCCs) and PCEs are presented in RFC 4657, "Path Computation Element (PCE) Communication Protocol Generic Requirements". Generic requirements for a PCE discovery protocol are presented in RFC 4674, "Requirements for Path Computation Element (PCE) Discovery".

This document complements the generic requirements and presents detailed sets of PCC-PCE communication protocol requirements and PCE discovery protocol requirements for inter-layer traffic engineering. This document is not an Internet Standards Track specification; it is published for informational purposes.')