03-12-2012, 11:39 AM
Mesh Based Multicast Routing in MANET: Stable Link Based Approach
Abstract:
The group-oriented services are one of the primary application classes that are addressed by mobile ad hoc networks (MANETs) in recent years. To support such services, multicast routing is used. Thus, there is a need to design stable and reliable multicast routing protocols for MANETs to ensure better packet delivery ratio, lower delays and reduced control overheads. In this paper, we propose a mesh based multicast routing scheme that finds stable multicast path from source to receivers. The multicast mesh is constructed by using route request and route reply packets with the help of multicast routing information cache and link stability database maintained at every node. The stable paths are found based on selection of stable forwarding nodes that have high stability of link connectivity. The link stability is computed by using the parameters such as received power, distance between neighboring nodes and the link quality assessed using bit errors in a packet. The proposed scheme is simulated over a large number of MANET nodes with wide range of mobility and the performance is evaluated. It is observed that proposed scheme produces better packet delivery ratio, less control overheads and reduced packet delay compared to on-demand multicast routing protocol (ODMRP).
Existing System:
Existing protocols are either tree- or mesh-based. Tree-based schemes establish a single path between any two nodes in the multicast group. These schemes require minimum number of copies per packet to be sent along the branches of the tree. Hence, they are bandwidth efficient. However, as mobility increases, link failures trigger the reconfiguration of the entire tree. When there are many sources, one either has to maintain a shared tree, losing path optimality, or maintain multiple trees resulting in storage and control overhead. Examples of tree-based schemes include [6][7][8]: ad hoc multicast routing protocol (AMRoute), ad hoc multicast routing utilizing increasing ID-numbers protocol (AMRIS), and multicast ad hoc on-demand distance vector routing protocol (MAODV).Mesh-based schemes establish a mesh of paths that connect the sources and destinations. They are more resilient to link failures as well as to mobility. The major disadvantage is that mesh-based schemes introduce higher redundancy of packets since multiple copies of the same packet are disseminated through the mesh, resulting in reduced packet delivery and increase in control overhead under highly mobile conditions.
Proposed System:
The tree management algorithm of HBH uses three control messages to construct an SPT. messages are periodically sent to the source by the receivers. The source periodically produces messages that are multicast to the receivers. As the messages travels in the tree, the intermediate nodes may generate messages that are responsible of refining the tree structure.In this project, we propose a link stability based multicast routing scheme that establishes a route from source to multicast destinations in MANET. A multicast mesh is created with stable links when a source node needs to send data to receiver nodes. The scheme consists of following phases.
A multicast channel in HBH is identified by , where is the unicast address of the source and is a class-D IP address allocated by the source. This definition solves the address allocation problem while being compatible with SSM’s channel definition. Therefore, HBH can support IP Multicast clouds as leaves of the distribution tree.