Most services borne by transport networks have been transitioned away from Time Division Multiplexing (TDM) towards IP-based. New technology is therefore required to effectively transport packet services. Multiprotocol Label Switching Transport Profile (MPLS-TP) is such a technology which is connection-oriented, capable of multiservice adaptation, and has a flexible label forwarding mechanism. This paper analyzes the characteristics of MPLS-TP, and introduces its latest standardization development. Key issues including data forwarding plane, service adaptation, and label forwarding mechanism are discussed, as well as service implementation of Virtual Private Network (VPN) based on dual-label transport. MPLS-TP applications are summarized in conclusion.

The merging of optical communication and wireless communication is a tendency in the development of future communication. Orthogonal Frequency Division Multiplexing (OFDM ) technology is becoming a core technology in the physical layer of next generation wireless communication system. Taking advantages of both wireless communication and optical communication, OFDM Radio over Fiber (OFDM-RoF ) system is characterized by high speed, large capacity and high spectral efficiency. However, it still has some problems to be addressed, including dispersion and nonlinearity effects. The nonlinearity effect of fiber and modulator can be mitigated by PAPR reduction algorithms, the dispersion effect can be eliminated using Cyclic Prefix (CP ) and channel estimation, and the fiber nonlinearity can be reduced by techniques such as digital phase conjugation, Partial Carrier Filling (PCF ), nonlinearity precompensation and serial correlation reduction.

The fast development of IP services forces the traffic flow in the networks to move gradually from Time Division Multiplexing (TDM ) services to packet data services. To adapt to the change, low-cost Ethernet technologies are introduced into the Metropolitan Area Network (MAN ). Ring network control protocols and ring network protection technologies are applied to guarantee manageability and reliability required in the telecom networks. The Ethernet Ring Protection (ERP ) and Resilient Packet Ring (RPR ) are two different ring protection technologies. The Transport Multi-Protocol Label Switching (T-MPLS ) network uses the T-MPLS Shared Protection Ring (TM-SPRing ) technology to provide ring protection. Carriers can expand the protection as needed and use appropriate ring technologies to meet the requirements of Carrier Ethernet (CE ).