Huawei Huawei Huawei This document describes the special requirements for applying the Path Computation Element (PCE) in Time-Division Multiplexing (TDM) networks, including Synchronous Optical Network (SONET), Synchronous Digital Hierarchy (SDH), and Digital Wrapper (G.709 ODUk). The material presented in this document is collected here for analysis. The intention is to separate this material into separate documents on generic GMPLS requirements, generic GMPLS extensions, and TDM-specific requirements and extensions. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].