The Multiprotocol Label Switching Transport Profile (MPLS-TP) is an extension of Multiprotocol Label Switching (MPLS), the protocol that allows most packets to be forwarded at the Layer 2 (switching) level rather than at the Layer 3 (routing) level.
MPLS-TP is designed to speed up and shape network traffic in telecommunications transport networks. In telecom, the transport network is composed of the equipment and fibers that physically transport signals. Transport networks have typically been built using Time Division Multiplexed (TDM) SONET/ SDH devices. However, these are becoming costly and ineffective. As a result, service providers are deploying more packet-based equipment in their transport networks. MPLS-TP helps with resilience and manageability by addressing typical packet technology deficiencies like end-to-end quality of service (QoS) and Operations, Administration and Maintenance (OAM) functions to detect and isolate faults.
MPLS-TP works by using Generalized MPLS (GMPL) to provide connection-oriented behavior using Label Switching Paths (LSPs). It also uses Targeted LDP (T-LDP) to set up pseudowires over GMPLS LSPs in order to provider Virtual Private Wire Service (VPWS) and Virtual Private LAN service (VPLS). MPLS-TP mandates running protocols such as Bi-direction Forwarding Detection (BFD) to provide operations, administration and maintenance (OAM) functionality. It also specifies how fast protection and restoration can be achieved using switchover to backup paths and allows LSPs and PWs to be signaled using a control plane or to be statically configured.