27-06-2014, 04:06 PM
Research on the Improvement of Multicast Ad Hoc On-demand Distance Vector in MANETS
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Abstract
Tree-based multicast routing provides fast and most
efficient way of routing establishment for the communications
of mobile nodes in wireless Ad Hoc networks. MAODV
(Multicast Ad Hoc On-demand Distance Vector) is one
commonly known tree-based multicast routing protocol, which
has minimal control overhead and route acquisition latency.
This paper presents a way to improve the throughput of the
system and reduce the number of mobile nodes participating in
multicast routing algorithms, which will significantly reduce
the routing-related control overhead. A systematic
performance evaluation is done by performing certain
simulations under NS-2.The applicability of these protocols to
diverse situation are also studied and discussed.
INTRODUCTION
Mobile ad hoc network (MANET) is a dynamically
reconfigurable wireless network with no fixed infrastructures.
Each node acts as a router and host, it moves in an arbitrary
manner. The Ad Hoc network (MANET) is a selfconfiguring
network of mobile nodes connected by wireless
link, which is full of electromagnetic and with a unstable
structure. [1] Multicasting in wireless Ad Hoc network is a
hot topic in recent years. A Mobile ad hoc network (MANET)
consists of a number of wireless hosts that communicate with
each other through multi-hop wireless links in the absence of
fixed infrastructures. In ad hoc network, if two nodes are not
within radio range, all message communication between
them must pass through one or more intermediate nodes. All
the nodes are free to move around randomly, thus changing
the network topology dynamically [2]. Multicasting means
the transmission of packets from a source or a group of
sources to a group of one or more hosts that are identified by
a single destination address. The system is so fragile which
makes typical Internet multicast protocols do not perform
well in MANET scenarios.
MULTIPATH ROUTING EXTENSIBILITY BASED ON MAODV
The Ad Hoc networks are multihop wireless networks,
each node can be both the receiver and relay station. To
archive one specify goal it requires all the hosts to
collaborate throughout the network Which makes the
multicast routing protocol very significant to the Ad Hoc
communications.
Each multicast group has a unique multicast group
address. According to the MAODV specification [5] [6],
each multicast group is organized by using a tree structure,
composed of the group members and several routers, which
are not group member but must exist in the tree to connect
the group members. Group leader of a multicast tree is the
one that first constructs the tree, which responsible for
maintaining the group tree by periodically broadcasting
Group-Hello (GRPH) messages in the whole network. The
group leader also maintains the group sequence number,
which is propagated in the network through the GRPH.
SIMULATION RESULTS AND ANALYSIS
To analyse multipath MAODV performance, simulated
MAODV under network simulator NS-2.26, and then
compare the results of MAODV with the multipath MAODV.
The network scenarios to be examined were chosen to mimic
the common scenarios chosen to test MANET routing
protocols.[
CONCLUSION
In this paper I propose one multipath routing protocol
base on MAODV. First source node chose the best latency
link as first link, relays using MACT-S message to create
one different link. And then, the source node sends out data
packets through two paths by the principle of load
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distribution, so as to balance network load and relieve the
congestion of network. Data transfer through both links can
increase the network utilization and reduce the congestion.
Simulation results indicate that: when network load
increased, multipath MAODV preferably ensures the
network performance and improve protocol's robustness.
Through increase multipath MAODV’s PDR perform better,
and effectively reduce Latency and network control overhead.
So multipath MAODV has better performance than
MAODV in relatively high load networks.