PCEP Extensions for SFC in SPRING Networks

[I-D.xu-spring-pce-based-sfc-arch] describes a PCE-based SFC architecture in which the PCE is used to compute service function paths in SPRING networks. Based on the above architecture, this document describes extensions to the Path Computation Element Protocol (PCEP) that allow a PCE to compute and instantiate service function paths in SPRING networks. The extensions specified in this document are applicable to both the stateless PCE model and the stateful PCE model.