Research On Route And Protection Restoration Technology For ASON

With the rapid development of Internet, data traffic on backbone increases explosively, so does the demand of IP service. For the reason that IP traffic is burst, changeful, uncertain and unpredictable, the bandwidth can not be fully used in SDH or WDM optical networks, and it is hard to allocation and it is complicate to operate. To adapt the new demands of network, the optical network technology of SDH and WDM is integrated with the intelligent network technology based on IP and formed the Automatic Switched Optical Network (ASON). ASON uses mesh-network configuration, imports control panel, advances the survivability and intelligence of optical network, so ASON needs more agility, intellegent and efficient route and protection & restoration technologys.This thesis focuses on route technology and protection & restoration technology of ASON. The main works and results of this thesis are as below:First, the function of each panels, connection modes and network models of ASON are studied. GMPLS protocol's extension of MPLS and the relationships between GMPLS and ASON are analyzed. And the relative technologys of IP network, SDH network and ASON are compared.Second, route modules and route patterns of ASON are researched, and the shortest path algorithms (Bellman-Ford, Dijkstra and A-Star) are compared and analyzed. To resolve the problem that the route results are decided by the route sequence encountered in traditional route algorithm, the thesis proposes a sequence-irrespective route algorithm. With the new algorithm, the route result is only decided by the network bandwidth status, not by the route sequence. New algorithm arranges traffics and computes routes with the best sequence. Experiment results show that this new algorithm can route more traffics and use less bindwidth resource under the same network status.Finally, the protection & restoration mechanisms of ASON are studied, the available protection & restoration technologys are discussed, and the application strategies of protection & restoration are analyzed. As a standard technology of protection & restoration, Shared Risk Link Group (SRLG) can extremely reduce the risk of both invalidity of active path and protection path. The concept and principle of path protection of SRLG are expounded, and the available SRLG-disjoint path protection algorithms are analyzed. Aimed at the common problem of "Trap" encountered in SRLG-disjoint path protection, a new SRLG-disjoint path protection algorithm based on "Trap" detection is proposed. The emulation results show that the new algorithm can detect and detour the "Traps", so as to decrease the congestion probability.