SMRS: A scalable multi-path routing scheme

Source routing has been extensively investigated as a method of improving diversity in path selection. Due to its limited scalability, the application of source routing is hindered today. Yang and Wetherall proposed a tag-based routing architecture to provide a set of non-shortest-path routes as an alternative to explicit source routes. The idea is that each router constructs a deflection set with the 1-hop route information and utilises tags as hints to independently deflect packets to the neighbours in the deflection set. To find more diverse paths, one approach is to increase the route knowledge of every node. However, there is a tradeoff in that more route knowledge leads to more diverse loop-free and dead end-free paths, but it also causes more overhead. In this paper, our objective lies in designing a method to find more diverse paths, with minimum knowledge. In addition, the tag-based deflection approach does not consider the length of the utilised paths as a main issue, which may lead to long paths. With this in mind, we propose a scalable multi-path routing scheme (SMRS), which consists of two components. One is the extension of the Yang and Wetherall approach to 2-hop history information. The other is the next hop selection algorithms to control the average length of the utilised paths. Comprehensive simulations are conducted to compare the performance of the tag-based deflection routing and SMRS.

Keywords

• multi-path routing,
• routing diversity,
• routing scalability,
• path selection