Extensions to Path Computation Element Communication Protocol (PCEP) for Hierarchical Path Computation Elements (PCE)
The Hierarchical Path Computation Element (H-PCE) architecture, defined in the companion framework document [I-D.ietf-pce-hierarchy- fwk], facilitates to obtain optimum end-to-end, multi-domain paths when the sequence of domains is not known in advance. Such H-PCE architecture allows the selection of an optimum domain sequence and, through the use of a hierarchical relationship between domains, derive the optimum end-to-end path. This document defines the Path Computation Element Protocol (PCEP) extensions for the purpose of implementing Hierarchical PCE procedures which are described the aforementioned document.