This document discusses the transition from TDM networks to packet-based networks, focusing on MPLS-TP as the best solution for mission critical applications. It notes that MPLS-TP can guarantee TDM-like deterministic performance for any network topology while providing packet efficiency. It also highlights that MPLS-TP offers transport-like protection, operation, and OAM that are important for low latency, jitter, and accurate timing in applications like teleprotection and synchronization. The document argues that MPLS-TP minimizes risk for mission critical networks during the inevitable change from TDM to packet.