Layered Pce Architecture Multi-domain Optical Network Path Calculation Method For The Research

The increasing of Internet services with high Quality of Service (QoS) requires pushing more challenges on inter-domain network engineering. Service providers may use Traffic Engineering (TE) techniques to manage network resources and provide expected QoS. Implementing TE in multi-domain multi-carrier networks, for instance multi-domain WDM optical network, is quite complex because of various constraints such as lacking of visibility, complex on optimization, and rigid confidentiality among domains. Among the candidates’solutions, the Path Computation Element (PCE) architecture is one of the most promising solutions since complex inter-domain path computation with QoS constraints is performed through dedicated PCE and dedicated communication protocol. The PCE can compute constrained inter-domain path using either Per-Domain or Backward Recursive PCE-based Computation (BRPC) procedure, in both of which the domain sequence which the inter-domain path will span is assumed to be predetermined.Firstly the background, motivation, and importance of our research are proposed, especially the Automatically Switched Optical Network and Generalized Multi-Protocol Label Switching.Secondly, we give an explicite introduction about PCE, which is the key technology of our research, the bachkground, motivation, architecture and communication mechanism between PCEs are included. We pay much attention on the inter-domain path computation based on the PCE architecture. We compare some existing algorithms, analysis the effect and the overhead of these algorithms, so as to find valuable problems to be further investigated:1. Proper topology aggregation method to solve inter-domain path computation problem in multi-domain optical network.2. Enhaced parallel computation approach for work and protection path.To solve the first problem, we propose a topology aggregation scheme named "Link-Vertex", together with the auxiliary "name scheme" and "link state mapping", to solve the "domain sequencing" problem in the inter-domain path computation in multi-domain optical network. Simulation results show that this scheme preserves more intra-domain routing information and provides more accurate inter-domain path, reduces inter-domain blocking probability, comparing with the traditional scheme.To solve the second problem, the survivability is another significant issue in our research on the multi-domain optical network. Our work focuses on the path protection, especially the computation of disjoint path. When the domain sequence of the work and protection path are the same, we propose an Enhanced Parallel Approach to reduce the computation overhead of exsting Parallel Approach. We also proposed a scheme to compute two disjoint paths without the same domain sequence.Finally, the main research of this paper is included; the problems in the proposed schemes are also highlighted.The main contribution and innovation of this paper include two aspects. The first is the "Link-Vertex" topology aggregation scheme, which gives a good performance on the inter-domain path computation. The second is the inter-domain disjoint path computation approaches, including the Enhanced Parallel Approach and the other approach under different domain sequence.This work was supported by the National Natural Science Foundation of China (61071101), the National High-Tech Research&Development Program of China (863programe,2009AA01Z254).