Research And Simulation On Fault-tolerant Topology Construction Algorithm In Space Information Networks

Due to the special circumstances in space information networks, spacecrafts are openly exposed to the space orbit, which are easy to be attacked. Once the network topology is destroyed seriously, it will affect the network performance directly. Therefore, the research on survivable and fault-tolerant topology control technology is of great significance to guarantee the stable operation of the system.A fault-tolerant topology construction algorithm CDFT was proposed, according to spatial relativity characteristics of the failure nodes. The topology control algorithm includes searching the half-plane, constructing the minimum spanning tree and fault-tolerant topology construction. The notion of convex region fault-tolerance is introduced and transferring the problem of convex region fault-tolerance into the problem of half-plane fault-tolerance. The searching algorithm of half-plane is used to find all the half-planes, and constructing fault-tolerant topology on each different half-plane. Based on AHP instead of the Euclidean distance, a minimum spanning tree is constructed. Bandwidth, delay, delay jitter and reliability of service are considered in AHP, which is to guarantee good network performance. The convex region fault-tolerant topology control algorithm is used in each half-plane, the union of that constructs the finial topology.The network simulation software NS2 was adopted to evaluate the proposed topology control algorithm. The results show that the propose algorithm can effectively optimize the network topology, reduce network bottlenecks, balance the network traffic for routing and load distribution and enhance the survivability and robustness of space information networks.