CiTRANS 650 is a grouping of MPLS - TP technology optical transmission platform, mainly located in the metropolitan area network of access layer, can effectively support the geographical position in a decentralized large customers, office buildings, residential area such as a large number of high-quality Ethernet/IP special business access and hosting services, also can well satisfy the IPTV, such as triple play of new business development needs. Meanwhile, in the mobile communication network, PTN technology is the carrying technology of future IP mobile access network (RAN). CiTRANS 650 can not only realize the carrying function of FE service back transmission of base station after RAN IP, but also take into account the access of traditional 2G base station and support ATM IMA E1 access processing.