A New Congestion Processing Scheme Based On Complementary Graph In Optical Network

In the early optical network, the configuration and connection, mainly depended on manual operation, are time-consuming and laborious. Which,of course, could not meet the demands of the development of information networks. ASON, an advanced optical network, is able to meet the growing needs of service operators due to its pretty flexible networking mode and the ability to provide faster service response to customers. The core of ASON is its control plane, which is the basis for realizing all the functions of the automatic switching optical network. And the control layer would have to rely on Generalized Multiprotocol Label Switching (GMPLS)protocol, which is commonly used in optical networks. GMPLS extends the MPLS protocol with the necessary architecture to control not only routers, but also DWDM systems, ADMs, optical cross-connect, etc. Links'failure often occurs in optical transportation network because of the increasing internet service traffic. Optical failure restoration is a hot issue in GMPLS protocol.This paper focuses on link failure problem in optical network. The main work and achievements of this paper are as follows:1 .This paper proposes a new failure recovery scheme: TMRC (Traffic Migration of Restoration in the Complement) recovery scheme. TMRC recovery scheme includes two new failure processing algorithms based on complementary graph in mathematical graph theory. The two new algorithms are TMRC failure prevention algorithm and TMRC failure repair algorithm. TMRC failure prevention algorithm aims at improving the traffic balance of the network to reduce the probability that a failure occurs. While TMRC failure repair algorithm aim at solving failure in an efficient way, if a failure occurs.2.The core idea of the TMRC recovery scheme is to solve the links'failure problem by transmitting the traffic on complementary graph of the optical network in a local scope. Compared to the traditional failure restoration scheme based on Floyd or Dijkstra algorithm, the GMPLS control plane would not traverse the entire optical network to build a totally new path in TMRC scheme. TMRC scheme focuses on traffic transmission only in a small range near the point where a failure occurs, thus it could improve the efficiency of failure restoration in the optical network by avoiding causing massive migration of traffic.3.Simulation experiments have been done to test the TMRC recovery scheme. And the results of these experiments show that compared to the traditional restoration scheme, TMRC reduces the average failure restoration time by 30%, increases the average utilization of the network resource by 16.6%, reduces the block rate by 12.5% when there is large amount of traffic, and reduces the average variance of the links' bandwidth utilization from 0.11 to 0.09, which means the traffic balance is improved.Thus the conclusion is that TMRC recovery mechanism promotes the overall network survivability.