PTN Layer 2 technologies can be seen as a simplified version of the mechanism and OAM enhancements combination. In the realization of the technology, the two main technical PBT and T-MPLS will be a substitute for SDH, rather than the IP/MPLS competitors, similar to its network theory, are based on end to end, bidirectional point to point connection, and provides a central management, within 50 milliseconds protection switchover; either can be used to implement SONET/SDH to packet switching transition, in the protection of existing transmission resources, it can be similar to the existing SDH network functions to implement the network packet switched network transformation.

T-MPLS (Transport MPLS) is a connection-oriented packet transport technology. In the transport network, the client signal is mapped into the MPLS frame and use MPLS mechanisms (such as label switching, the label stack) forwards, while it increases the basic functions of the transport layer, such as connectivity and performance monitoring, survivability (protection and restoration), management and control plane (ASON/GMPLS).