Path Computation Element Communication Protocol (PCEP) Extensions to Enable IFIT

In-situ Flow Information Telemetry (IFIT) refers to network OAM data plane on-path telemetry techniques, in particular In-situ OAM (IOAM) and Alternate Marking. This document defines PCEP extensions to allow a Path Computation Client (PCC) to indicate which IFIT features it supports, and a Path Computation Element (PCE) to configure IFIT behavior at a PCC for a specific path in the stateful PCE model. The application to Segment Routing (SR) is reported. However, the PCEP extensions described in this document can be generalized for all path types, but that is out of scope of this document.