14-11-2012, 02:47 PM
Agent based multicast routing in MANETs
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Abstract
Multicast routing in Mobile Ad hoc Networks
(MANETs) poses several challenges due to inherent
characteristics of the network such as node mobility,
reliability, scarce resources, etc. This paper proposes
an Agent Based Multicast Routing Scheme (ABMRS) in
MANETs, which uses a set of static and mobile agents.
The scheme operates in the following sequence: 1)
identies reliable nodes, 2) connects the reliable nodes
through intermediate nodes, 3) constructs a backbone for
multicasting using reliable nodes and intermediate nodes,
4) joining multicast group members to the backbone, 5)
backbone management and group members management
in case of mobility. Five types of agents are used in
the scheme : Route manager agent (static), Network
initiation agent (mobile), Network management agent
(static), Multicast initiation agent (mobile), and Multicast
management agent (static).
Introduction
Mobile Ad hoc Networks (MANETs) comprises of mobile
nodes that communicate over multi-hop wireless
links without the support of any infrastructure such as
base stations. Multicasting is intended for group-oriented
computing like video conferencing, collaborative works,
etc., and its use within a network has many benets. Multicasting
reduces the communication costs for applications
that send the same data to multiple recipients. It
minimizes the link bandwidth consumption, sender and
router processing, and delivery delay. As a result, multicast
routing has become a research focus recently, and
various multicasting protocols for MANET have been
proposed.
Software agents
The traditional programming paradigm uses functions,
procedures, structures and objects to develop a software
for performing a given task. This paradigm does not support
development of exible, intelligent and adaptable
softwares, and also does not facilitate all the requirements
of Component Based Software Engineering (CBSE) [6] -
[8]. In recent developments, agent technology is making
its way as a new paradigm in the areas of articial intelligence
and computing, which facilitates sophisticated
software development with features like exibility, scalability
and CBSE requirements [9] [10].
ProposedWork
Agent Based Multicast Routing Scheme (ABMRS) in
MANETs uses a set of static and mobile agents. This section
describes the network environment, routing agency
and the routing scheme.
Network Environment
We consider a MANET comprising of several nodes that
are randomly distributed across a given geographical area
as given in gure 1. It comprises of a backbone formed
by using reliable nodes. A reliable node can communicate
to another reliable node using some intermediate
nodes. Multicast group members are attached to any one
of the reliable node. All the reliable nodes support multicast
operations whereas intermediate nodes just forward
packets from one reliable node to another reliable node.
Group member nodes (child to reliable nodes), reliable
nodes and intermediate nodes may move from one place
to another place (mobility). In case of mobility, multicast
routes will be recongured by using different set of
reliable and intermediate nodes. All the nodes consist of
mobile agent platform that supports communication, mobility,
security and persistence.
Simulation
The proposed model has been simulated in various network
scenarios on a Pentium-4 machine by using C++
programming language. In this section we describe the
simulation model and the simulation procedure.
Simulation model
A mobile ad-hoc network consisting of n nodes is generated
by using a random placement of the nodes and
allowed for the free movement within the area of lXb
square meters. The communication range for each node
is selected as Cran. The reliability factor of each node is
in between the range of P to Q. Nodes can move in the
speed range X to Y meters/second. A multicast group may
comprise of Mmem member nodes, which are randomly
selected among the existing nodes.
Number of packets generated from a node in group
communication are randomly distributed between w to z.
Each node starts from a random location and moves in
any one of the eight directions: North, south, East, West,
Northwest, and southwest. If a node tries to go out of the
boundary its direction is reversed (Bouncing ball model).
Conclusions
This paper proposed an agent based multicast routing
protocol for mobile ad hoc networks. The new routing
scheme ABMRS is based on packet forwarding with the
help of intermediate nodes and reliable nodes. ABMRS
effectively routes data packets to group members even in
case of high mobility, i.e., it has higher packet delivery
ratio as compared toMAODV. ABMRS has good exibility
and adaptability. Adaptation can be seen in ABMRS,
where agents reconstruct backbone upon sensing mobility
or any fault conditions in the network. The work can
be extended to construct multiple multicast trees to provide
fault redundancy.