Research On Chord Algorithm Based On Physical Topology Awareness

In the current Internet architecture, IP address is used to represent an identity of a legal internet user and its locator in the network by using its network number, which means the IP address possesses double identities. The ambiguity of IP address caused serious routing scalability problems in Internet, and led to the result that the Internet is difficult to further support the mobility and multihoming. The project of Universal trustworthy Network and pervasive Services belongs to the National Basic Research Program (973 Program).The project team proposes the universal trustworthy Network model, which realizes the separation of the identity and location by introducing two identifiers Access Identifier (AID) and Routing Locator (RLOC), where AID represents the identifier of the terminal and RLOC represents the locator of the terminal. The separation of identifier and locator could solve the problems caused by double identity of IP address in traditional network.RLOC and AID need the mapping to interrelate with each other and therefore require an efficient mapping information resolution mechanism to store and query the mapping between the two identifies. This paper researches on the key technologies of the mapping information resolution, which aims at solving the distributed storage of the massive identifier mapping information items. Based on the character of hierarchy and aggregation in RLOC structure, chooses the Chord which is a classic data sharing method in P2P technology as the basic storage network model, and focusing on the physical topology mismatch problem in Chord, proposed a physical topology awared Chord model (Ant-Chord) which based on ant colony algorithm. The ideas of Ant-Chord is to regard the storage nodes in the whole Chord as a TSP problem and solve the TSP problem quickly by using the ant colony algorithm, then to build the Chord with the obtained TSP solution, and proposed a method which called "Luoyang shovel" to optimize the Ant-Chord's routing hops.The model is simple and easy to implement, which has small changes within the original Chord model and little extra overhead cost in the routing table storage. Simulation results show that, Ant-Chord has obvious advantages in average routing hops and delay in comparison with other Chord models. So as to the Chord construction program of the identity mapping separation network and even under the existing network, and to the reseaches of physical topology matching, Ant-Chord model may provide another idea for reference.