Research And Application On Structured ID Based Chord Protocol

Structured peer-to-peer overlay networks such as CAN Chord Pastry and Tapestry provide a scalable and robust data location and request routing service for large-scale distributed applications such as decentralized storage and content distribution. They provide a Distributed Hash Table (DHT) function for mapping keys to overlay nodes. Resource locating arithmetic such as Chord got great attention. A node participating in an overlay is assigned a random m-bit identifier from a numeric space, and the identifier is usually assigned by using consistent hashing arithmetic such as SHA-1. All those possible 2~m identifiers will construct a one dimension identifier ring, according to which an overlay network is formed above the physical network.Although storage load is balanced because of hash functions, the overlay topology is not congruent with the physical topology as well. For example, two nodes N1 and N2, with IP address "59.64.157.38" and "59.64.157.39", they are proximate in the physical network, and generally speaking, they belong to the same local area network. However, identifier Hash(59.64.157.38) and Hash(59.64.157.39) may be rather different. As a result, these two nodes will be far away from each other in the overlay network, and can potentially traverse a long-haul link when routing for each other. To address this issue, we promote the use of location-based structured node ID to encode physical topology and improve routing. This helps nodes proximate to one another in the physical to be proximate in the overlay network as much as possible, and when the two nodes above want to access each other, long-haul links may be avoided.In this paper, a method taking advantage of structured node ID is promoted based on the research of Chord protocol, and iterative style Chord simulator is designed and implemented for experiment and analysis. Experimental results show that structured node ID help to...