Research On PTN Carrying Network Construction Solution To LTE Networks

As the next generation of mobile wireless network LTE （Long Term Evolution）develops, new wireless network infrastructure makes some important demands overtransport network. First of all, transport network should have a universal platform withcapacity for packet processing. Secondly, transport network should have strong scalability.Finally, it also should have operation administration and maintenance (OAM) and securityprotection service.Facing the requirements of LTE return net and IP data business, there are two kinds ofmainstream packet transport network technology, one is PTN(Packet Transport Network)technology, based on MPLS-TP, co-release by IETF and ITU-T. The other is IP RAN,based on IP/MPLS, released by IETF. The purpose of the two technologies is to realizeend-to-end connection based on packet switching, carry all kinds of services (Ethernet,TDM, ATM, etc.), achieve hierarchical and end-to-end OAM, support flow control. Thesetwo technology are different in lines of evolution, first of all, the function of PTN isstronger than IP RAN in the OAM and maintenance management. Secondly, in the respectof network security and reliability, PTN provides perfect protection mode, while IP RANhas only a single protection mechanism. Once again, in view of openness, PTN’s industrialchain and standard is mature than IP RAN, and has strong compatibility with MSTPnetwork. Finally, with respect to single set of equipment and the whole net construction,PTN equipment based on2-layer has significant advantages in cost. Main research of thispaper is construction solution of LTE system with PTN Carryring Network.Enter the LTE4G stage, LTE core network introduce EPS standard architecture, thusPTN network faces new challenges: delay of S1/X2interface in wireless return net, higherbandwidth demand, higher QoS requirement, new forward demand, time synchronizationbased on1588v2, for new requirements, find a more reliable, feasible construction schemewhich packet transmission network can evolution smoothly.This paper mainly introduces two evolution construction ideas. First, the idea of PTN+CE construction, introducing the routing layer concept and new CE router to realizerequirements of LTE and S1/X2data forwarding. Second, the introduction of PTN withL3function, on the basis of present networks, constructing a new PTN L3core layer anddata service end layer, without router intervention it will realize the requirements of LTEreturn net. Under PTN+CE construction mode, connectivity and reliability of S1/X2, CE DHCP ReLay, CE and PTN802.3ah and Qos are tested. Under PTN L3construction mode,bridge effect of L2and L3, routing protocol between PE, end-to-end load carrying functionof S1/X2, end-to-end protection of S1/X2, OAM performance and end-to-end timesynchronization function are tested. Through the above test we evaluate economy andfeasibility of these two kinds of solution, and at the same time, draw lessons duringconstruction cycle, considering choice of number of network elements nodes and selectionof equipment and equipment using principle in hierarchical construction, we summarizedexperience of hierarchical construction.The research and achievements in this paper provides technical reference for LTEcarrring evolution direction which are based on PTN technology.