Routing Protocols

Routing Protocols

  • Submitted By: rameshrajan
  • Date Submitted: 11/30/2013 8:49 PM
  • Category: Business
  • Words: 2402
  • Page: 10
  • Views: 66

Part 4. Routing Protocols
1. Routing for Mobile Ad hoc NETworks (MANETs) Routing in MANETs is difficult since mobility causes frequent network topology changes and requires more robust and flexible mechanisms to search for and maintain routes. When the network nodes move, the established paths may break and the routing protocols must dynamically search for other feasible routes. With a changing topology, even maintaining connectivity is very difficult. In addition, keeping the routes loop free is more difficult when the hosts move. Besides handling the topology changes, routing protocols in MANETs must deal with other constraints, such as low bandwidth, limited energy consumption, and high error rates, all of which may be inherent in the wireless environment. Furthermore, the possibility of asymmetric links, caused by different power levels among mobile hosts and other factors such as terrain conditions, make routing protocols more complicated. 1.1 Categories of Existing Routing Protocols for MANETs Many protocols have been proposed for MANETs. These protocols can be divided into three categories: proactive, reactive, and hybrid. Proactive methods maintain routes to all nodes, including nodes to which no packets are sent. Such methods react to topology changes, even if no traffic is affected by the changes. They are also called table-driven methods. Reactive methods are based on demand for data transmission. Routes between hosts are determined only when they are explicitly needed to forward packets. Reactive methods are also called on-demand methods. They can significantly reduce routing overhead when the traffic is lightweight and the topology changes less dramatically, since they do not need to update route information periodically and do not need to find and maintain routes on which there is no traffic. Hybrid methods combine proactive and reactive methods to find efficient routes, without much control overhead. 1.2 Proactive Routing Protocols As stated...

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