Optimized Multicast Routing Algorithm Based on Tree Structure in MANETs

Abstract:

Multicasting plays an important role in the typical application of ad hoc wireless networks namely, emergency search andrescue operations, military applications etc. nodes form groups to carry out certain tasks that require point-to-point and multipoint-to-multipoint voice and data communications. The arbitrary moment of nodes, with the constraints of power source and bandwidth makes multicast routing very challenging. There are two types of multicasting Ad-hoc routing structure, first one Tree based structure it delivers data from source to destination in the form of tree structure. It provides high mobility efficiency, with low packet delivery ration due to the frequent tree breaks; the second mesh based structure is a connected component of the network containing all receivers of group. Multiple links among the nodes in an ad-hoc wireless network results in a mesh-shaped structure. The mesh based multicast routing structure may work on high mobility environment. There are several multicast routing protocols plays important role in mobile ad-hoc networks (MANETs). We observe that tree-basedones have high forwarding efficiency and low consumptions of bandwidth, and they may have poor robustness because only one link exists between two nodes. As a treebased multicast routing protocol, MAODV (Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.

Algorithm:- MAODV

Analyze the impact of network load on MAODV protocol, and propose an optimized protocol MAODV-BB (Multicast Ad hoc On-demand Vector with Backup Branches), which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure. It not only can update shorter tree branches but also construct a multicast tree with backup branches. Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.

Proposed System:-

Multicasting plays an important role in the typical application of ad hoc wireless networks namely, emergency search and rescue operations, military applications etc. nodes form groups to carry out certain tasks that require point-to-point and multi -point-to-multipoint voice and data communications. The arbi-trary moment of nodes, with the constraints of power source and bandwidth makes multicast routing very challenging. An ad-hoc routing protocol is a convention, that controls how nodes decide which way to route packets between more than one devices in a mobile ad-hoc network. Multicasting is in tended for group communication that supports dissemination of information from a sender to all receivers in a group. It’s the ability of communication network to accept a single message from an application and to deliver copies of the same message to multiple recipients, at different location. One of the challenges is to minimize the amount of network resources employable by multicasting.The multicast distribution tree of receiving hosts holds the route to every recipient that has joined the multicast group, and is optimized so that

multicast traffic does not reach networks that do not have any such recipients (unless the network is a transit network on the way to other recipients)

duplicate copies of packets are kept to a minimum.

Future Enhancement:-

As further work, we intend to study the reliability of tree-based multicast routing protocols in varying conditions such as node mobility, group size. We also consider enhancing our protocol with a global congestion control mechanism to slow the data rate of the senders when the network is highly loaded The multicast operation of the Ad hoc On-Demand Distance Vector (AODV) routing protocol (MAODV) is intended for use by mobile nodes in an ad hoc network. It offers quick adaptation to dynamic link onditions, low processing and memory overhead, and low network utilization. It creates bi-directional shared multicast trees connecting multicast sources and receivers. These multicast trees are maintained as long as group members exist within the connected portion of the network. Each multicast group has a group leader whose responsibility is maintaining the group sequence number, which is used to ensure freshness of routing information.

Module:-

Root Trees

A Multicast Group Membership Discovery protocol is used by receiving hosts to advertise their group membership to a local multicast router, enabling them to join and leave multicast groups. The main Multicast Group Membership Discovery protocols are Internet Group Management Protocol (IGMP) for IPv4 and Multicast Listener Discovery (MLD) for IPv6. In the event that a link break cannot be repaired, the multicast tree remains partitioned until the two parts of the network become connected once again. A node from one partition of the network knows that it has come into contact with a node from the other partition of the network by noting the

difference in the GRPH message multicast group leader information. The multicast group leader with the lower IP address initiates the tree repair.

Routing Table Management:-

MAODV is a routing protocol, and it deals with route table management. Route table information must be kept even for ephemeral routes, such as are created to temporarily store reverse paths towards nodes originating RREQs. MAODV uses the following fields with each route table entry, which are based on the route table defined in the AODV

Data Packet:-

A Multicast Routing Protocol is used to communicate between multicast routers and enables them to calculate the multicast distribution tree of receiving hosts. Protocol Independent Multicast (PIM) is the most important Multicast Routing Protocol. When multiple interfaces are available, a node receiving and rebroadcasting a RREQ or GRPH message rebroadcasts that message on all interfaces except the one on which it was received. If a node is participating on the multicast tree, and if multicast data packets are being sent as broadcast traffic, a multicast tree node should only rebroadcast a packet on those interfaces which have multicast tree next hops.

Multicast Group:-

There are two types of multicasting Ad-hoc routing structure, first one Tree based structure it delivers data from source to destination in the form of tree structure. It provides high mobility efficiency, with low packet delivery ration due to the frequent tree breaks; the second mesh based structure is a connected component of the network containing all receivers of group. Multiple links among the nodes in an ad-hoc wire less network results in a mesh-shaped structure. The mesh based multicast routing structure may work on high mobility environment.

H/W System Configuration:-

Processor - Pentium –III

Speed - 1.1 Ghz

RAM - 256 MB(min)

Hard Disk - 20 GB

Key Board - Standard Windows Keyboard

Mouse - Two or Three Button Mouse

Monitor - SVGA

S/W System Configuration:-

Operating System : Windows XP / 7

Front End : JAVA,RMI, SWING.