Macromobility support for mobile ad hoc networks using IPv6 and the OLSR routing protocol

摘要

Mobile ad hoc networks (MANETs) make use of a distributed routing mechanism to support connectivity between nodes within the ad hoc network. A wireless ad hoc network can be deployed for multiple applications, for example, it can be used to extend the coverage of wire-based networks through the use of a wireless access router. However, the implementation of a hybrid (i.e. wired and wireless) network is not a straight forward process and several issues must be solved for this type of topologies to become a reality. One concern is related to terminal mobility while preserving ongoing communication sessions; as a mobile node moves from one subnetwork to a new subnetwork a mobility protocol must be introduce to allow the mobile node to preserve communication sessions without having to reestablish the session with a correspondent node; this issue becomes more complex in a hybrid network where the wireless domain is composed by a mobile ad hoc network (MANET). For instance, MANET routing protocols usually do not account for the connectivity toward a wired network, such as the Internet. As a result there are multiple routing issues that must be taken into consideration for the support of interconnectivity between nodes located in a hybrid network. In this work we assume that a hybrid network has been deployed and the optimized link state routing (OLSR) protocol is implemented in the ad hoc network; in addition, we consider the implementation of a macromobility mechanism under IPv6. The support of macromobility is achieved via Mobile IPv6, while OLSR provides the routing capabilities within the MANET. The main contribution of this work is the proposal of diverse strategies to improve the layer 3 handoff latency, as a mobile node roams between foreign networks.