For scalability purposes, a network may comprise multiple Interior Gateway Protocol (IGP) areas. An inter-area Traffic Engineered Label Switched Path (TE-LSP) is an LSP that transits through at least two IGP areas. In a multi-area network, topology visibility remains local to a given area, and a head-end Label Switching Router (LSR) cannot compute an inter-area shortest constrained path. One key application of the Path Computation Element (PCE)-based architecture is the computation of inter-area TE-LSP paths. The PCE Communication Protocol (PCECP) is used to communicate computation requests from Path Computation Clients (PCCs) to PCEs, and to return computed paths in responses. This document lists a detailed set of PCECP-specific requirements for support of inter-area TE-LSP path computation. It complements the generic requirements for a PCE Communication Protocol. This memo provides information for the Internet community.