Research Of Multi-Traffic’s Transport Performance And Local Protection Technologies For Mpls-Tp Networks

T-MPLS is a MPLS-based, connection-oriented packet transport technology, which is initiated by ITU-T in2006and can give better support to current data traffic in growth. Later in2008, a joint work group was founded by ITU-T and IETF, and developed T-MPLS technology to MPLS-TP. Since MPLS-TP has desired end to end OAM capabilities like SDH, and provides better Carrier-grade Quality of Services (QoS) for upper layer traffic like Ethernet, IP and TDM, it has been regarded as a promising technology for next generation packet transport networks (PTNs). In recent years, the functional structures, operating schemes, and applications of MPLS-TP technology have been researched a lot and have achieved a great success. However, on one hand, the problem of QoS support to multi-class, multi-feature upper layer traffic is very important but lack of investigation. On the other hand, as to the solutions of survivability problem, schemes employed now are all based on end to end linear or ring protection, which usually cost longer restoration time than local protection schemes.With the financial support of the High-Tech Research and Development Program of China, this thesis investigates the transport performance of multi-class traffic and local protection schemes for network links and nodes thoroughly, by studying corresponding theories and protocols, and developing software simulation testbed according to relative standards and protocols. The main work and innovative achievements are as follows:Firstly, as to the problem of MPLS-TP networking schemes, we presented a mesh topology based, OTN integrated metro packet transport platform model. In addition, we constructed a MPLS-TP simulation testbed by using OPNET modeler, with the implementation of ASON/GMPLS network control functions, in-band OAM monitoring and traffic’s dual label transport mechanisms.Secondly, as to the problem of multi-class hybrid traffic transmission, we proposed a theoretical QoS model for packet traffic. Under the assumption that the edge node gives preemptive priority to TDM traffic, we obtained the queue-length distribution and packet loss probabilities of the Poisson and MMPP traffic in the system with the help of embedded Markov chain. The theoretical results fit well with simulation results. Our analysis shows the best TDM payload length for transmission is between16×200bytes and32×200bytes. Our work makes it possible to study the coupling among the various system parameters and to predict, explain, and fine tune the performance of the PTN edge node.Thirdly, as to the problem of scheduling self-similar packet traffic in MPLS-TP networks, we purposed a novel scheduling algorithm which improving bandwidth utilization of links in MPLS-TP networks. Then, the algorithm is implemented in the simulation testbed for performance evaluation. Simulation results show that, compare with traditional scheduling algorithms, this algorithm not only saves bandwidth of links but also makes high class services acquire a better time-delay performance, without increasing algorithm complexity.Fourthly, we studied encapsulated packet length of circuit traffic in MPLS-TP networks. Then, an adjustment scheme was proposed to change the packet length dynamically. With the consideration of the real-time conditions of the traffic’s latency and variance, this scheme calculates the suitable payload sizes in the destination node and provides feed-back to the source node, in order to adjust this size in the adaptation module. At last, we compared the performance of the multi-class packet traffic according to different TDM packet length. Simulation results show that the feature of self-similarity and traffic generation laws have different level effect on high class packet services, which including latency and it’s variance, queue length and packet lost rate at the routers’ egress. Fifthly, as to the problem of MPLS-TP local protection, we presented a suite of hybrid protection schemes for MPLS networks that combine the well-known P-cycle method with FRR technology. Whereas with pure FRR backup paths are planned by each node individually, the hybrid schemes employ a set of P-cycles that may be selected using techniques that take a holistic view of the network so as to share protection bandwidth effectively. The hybrid FRR/P-cycle methods are fully RFC4090-compliant, yet allow network operators to leverage a large existing body of p-cycle design techniques. Numerical results on realistic network topologies indicate that the hybrid approach is successful in combining the advantages of P-cycle design and FRR, which can save the protection bandwidth more than20%, and decrease the protection label cost more than-40%.