A Link-Disjoin Multipath Routing Algorithm Based On DYMO

Wireless network has attracted more and more attention in the field of communication science since 1970s. It can be categorized into two kinds: one is center-controlled network such as Wireless Local Area Network, the other is self-organized wireless network with no access points such as Ad hoc network. The Ad hoc network is receiving increasing attention and application due to its mobility and convenience it can provide to people.The Ad Hoc Network owns some characteristics such as self-organization, multi-hop and a frequently-changed topology. The uniqueness of the Ad hoc Network makes it impossible to adopt the technologies utilized in traditional networks. So some new protocols and technologies need to be developed specially for the Ad hoc network on channel access, network security and routing. Various routing protocols that are tailored to Ad Hoc networks have been put up in recent years by researchers around the world and related analysis are being done from different aspects. However many routing algorithms focus on the establishment of a single path between the source and the destination. But multiple routes have been proved beneficial, when used either for load balancing or as backup routing paths. In this paper, we focus on the routing protocols and algorithms of Ad Hoc network, choose the Dynamic Manet On-demand Routing Protocol as our main research point and modify it to multipath routing arithmetic in order to achieve more advanced performance.This paper firstly introduces the Ad hoc network and its routing protocols, then simply introduces some of prevalent single-path routing protocols in MANETs. Following these, the paper focuses on explaining the DYMO protocol and explains the differences between single-path routing protocol and multi-path routing protocol, the differences between independent multi-path routing algorithm and normal multi-path routing algorithm. Furthermore, the paper analyzes the stability and the optimum number paths of multipath by math deducting. At last, based on the DYMO protocol, the paper proposes a new link-disjoint multipath routing arithmetic and explains the new arithmetic in detail.MDYMO arithmetic, based on DYMO, uses new route discover policy and updating policy compared with original DYMO protocol. Using one finding-routes process of the source, the new arithmetic can attaint some link-disjoint routes which can be stored as back-off routes. By these means, the new arithmetic could be more suited for the mobility and incur the performances improved. Except these, MDYMO arithmetic maintains most of other mechanism in DYMO, such as monitor policy in link layer, exponential back-off policy etc. So there are not so many aspects need to be modified in the new arithmetic compared with DYMO. Therefore, the whole new arithmetic is not very complex and it is easy to be expanded for the future.Using NS, a network simulation tool, the paper compares the performance of MDYMO with DYMO protocol. In varied scenarios we simulated, the results showed that MDYMO is more efficient than DYMO in the end to end delay and packet delivery ratio and also normalized routing overhead. The results also showed that multipath routing protocols were superior to single routing protocols over network performance again.