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Novel Technique for Improving Performa

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					National Conference on Role of Cloud Computing Environment in Green Communication 2012
                                                                                                                                 200


                                    Novel Technique for Improving Performance In
                                             Mobile Ad Hoc Networks
                                     Greeshma Sudha.B#1, Natarajan.R,M.Tech.,*2
                            #1
                              II PG Student,The Rajaas Engineering college,Vadakangulam,
                                             Tirunelveli,Tamilnadu,India.
                                            E-mail:greeshmasudha@gmail.com

                       *2
                         Assistant Professor, The Rajaas Engineering college,Vadakangulam,
                                            Tirunelveli,Tamilnadu,India.

Abstract— Group communications are important in                   Conventional MANET multicast protocols can be ascribed
Mobile Ad hoc Networks (MANET). Multicast is an                into two main categories, tree-based and meshbased. However,
efficient method for implementing group communications.        due to the constant movement as well as frequent network
However, it is challenging to implement efficient and          joining and leaving from individual nodes, it is very difficult
scalable multicast in MANET due to the difficulty in           to maintain the tree structure using these conventional tree-
group membership management and multicast packet               based protocols. The mesh-based protocols are proposed to
forwarding over a dynamic topology. In this paper a novel      enhance the robustness with the use of redundant paths
Efficient Geographic Multicast Protocol (EGMP) is              between the source and the destination pairs. Conventional
proposed. EGMP uses a virtual-zone-based structure to          multicast protocols generally do not have good scalability due
implement scalable and efficient group membership              to the overhead incurred for route searching, group
management. A network-wide zone-based bi-directional           membership management, and creation and maintenance of
tree is constructed to achieve more efficient membership       the tree/mesh structure over the dynamic MANET. For
management and multicast delivery. The position                MANET unicast routing, geographic routing protocols have
information is used to guide the zone structure building,      been proposed in recent years for more scalable and robust
multicast tree construction and multicast packet               packet transmissions. The existing geographic routing
forwarding, which efficiently reduces the overhead for         protocols generally assume mobile nodes are aware of their
route searching and tree structure maintenance. The            own positions through certain positioning system(e.g., GPS),
scalability and the efficiency of EGMP are evaluated           and a source can obtain the destination position through some
through simulations and quantitative analysis.                 type of location service. An intermediate node makes its
                                                               forwarding decisions based on the destination position
Index Terms—Routing, wireless networks, mobile ad hoc          inserted in the packet header by the source and the positions
networks, multicast, protocol,EGMP.                            of its one-hop neighbors learned from the periodic beaconing
                                                               of the neighbors. By default, the packets are greedily
                       I. INTRODUCTION                         forwarded to the neighbor that allows for the greatest
                                                               geographic progress to the destination. When no such a
   A mobile ad hoc network (MANET), is a self-configuring neighbor exists, perimeter forwarding is used to recover from
infra-structure less network of mobile devices connected by the local void, where a packet traverses the face of the
wireless links. Each device in a MANET is free to move planarized local topology sub graph by applying the right-
independently in any direction, and will therefore change its hand rule until the greedy forwarding can be resumed.
links to other devices frequently. Each must forward traffic      Similarly, to reduce the topology maintenance overhead
unrelated to its own use, and therefore be a router. The and support more reliable multicasting, an option is to
primary challenge in building a MANET is equipping each makeuse of the position information to guide multicast
device to continuously maintain the information required to routing.However, there are many challenges in implementing
properly route traffic. Such networks may operate by anefficient and scalable geographic multicast scheme in
themselves or may be connected to the larger Internet. A MANET.For example, in unicast geographic routing, the
"mobile ad hoc network" (MANET) is an autonomous system destination position is carried in the packet header to guide the
of mobile routers (and associated hosts) connected by wireless packet forwarding, while in multicast routing, the destination
links the union of which form an arbitrary graph. The routers is a group of members. A straight-forward way to extend the
are free to move randomly and organize themselves arbitrarily; geography-based transmission from unicast to multicast is to
thus, the network's wireless topology may change rapidly and put the addresses and positions of all the members into the
unpredictably. Such a network may operate in a standalone packet header, however, the header overhead will increase
fashion, or may be connected to the larger Internet. Sensor significantly as the group size increases, which constrains the
nodes consist of sensing, data processing, and communication application of geographic multicasting only to a small group.
components and typically form ad hoc networks.                 Besides requiring efficient packet forwarding, a scalable
                                                               geographic multicast protocol also needs to efficiently manage




Department of CSE, Sun College of Engineering and Technology
National Conference on Role of Cloud Computing Environment in Green Communication 2012
                                                                                                                                       201

the membership of a possibly large group, obtain the positions     calculated based on the position of the node With a destination
of the members and build routing paths to reach the members        location, a control message can be transmitted immediately to
distributed in a possibly large network terrain.                   find the path first, which enables quick group joining and
   The existing small-group-based geographic multicast             leaving Introducing an important concept zone depth, which is
protocols normally address only part of these problems. In this    efficient in guiding the tree branch building and tree structure
work, we propose an efficient geographic multicast protocol,       maintenance, especially in the presence of node mobility.
EGMP, which can scale to a large group size and large              With nodes self-organizing into zones, zone based bi-
network size. The protocol is designed to be comprehensive         directional-tree-based distribution paths can be built quickly
and self-contained, yet simple and efficient for more reliable     for efficient multicast packet forwarding. Addressing the
operation. Instead of addressing only a specific part of the       empty zone problem, which is critical in a zone-based
problem, it includes a zone-based scheme to efficiently handle     protocol, through the adaption of tree structure.
the group membership management, and takes advantage of
the membership management structure to efficiently track the       A.   EGMP
locations of all the group members without resorting to an             In EGMP the tree-based protocols construct a tree
external location server. The zone structure is formed virtually   structure for more efficient forwarding of packets to all the
and the zone where a node is located can be calculated based       group members. EGMP uses a location-aware approach for
on the position of the node and a reference origin. In             more reliable membership management and packet
topology-based cluster construction, a cluster is normally         transmissions, and supports scalability for both group size and
formed around a cluster leader with nodes one hop or k-hop         network size.
away, and the cluster will constantly change as network
                                                                      1) Protocol Overview
topology changes. In contrast, there is no need to involve a big
overhead to create and maintain the geographic zones                  EGMP supports scalable and reliable membership
proposed in this work, which is critical to support more           management and multicast forwarding through a two-tier
efficient and reliable communications over a dynamic               virtualzone-based structure. At the lower layer, in reference to
MANET. By making use of the location information, EGMP             a pre-determined virtual origin, the nodes in the network self-
could quickly and efficiently build packet distribution paths,     organize themselves into a set of zones as shown in Fig. 1,
and reliably maintain the forwarding paths in the presence of
network dynamics due to unstable wireless channels or
frequent node movements.
   .

                 II. EXSISTING METHOD

    Conventional topology-based multicast protocols include
tree-based protocols and mesh-based protocols. Tree-based
protocols construct a tree structure for more efficient
forwarding of packets to all the group members. However,
due to the constant movement as well as frequent network
joining and leaving from individual nodes, it is very difficult
to maintain the tree structure using these conventional tree-
based protocols. The mesh-based protocols are proposed to
enhance the robustness with the use of redundant paths
between the source and the destination pairs. Conventional         Fig. 1: Zone structure and multicast session example.
multicast protocols generally do not have good scalability due
to the overhead incurred for route searching, group                   And a leader is elected in a zone to manage the local group
membership management, and creation and maintenance of             membership. At the upper layer, the leader serves as a
the tree/mesh structure over the dynamic MANET.                    representative for its zone to join or leave a multicast group as
                                                                   required. As a result, a network-wide zone-based multicast
                  III. PROPOSED SCHEME                             tree is built. For efficient and reliable management and
                                                                   transmissions, location information will be integrated with the
   EGMP uses a location-aware approach for more reliable           design and used to guide the zone construction, group
membership management and packet transmissions, and                membership management, multicast tree construction and
supports scalability for both group size and network size. In      maintenance, and packet forwarding. The zone-based tree is
EGMP, instead of connecting each group member directly to          shared for all the multicast sources of a group.
the tree, the tree is formed in the granularity of zone with the
                                                                   B.  Neighbortable generation and zoneleader election
guidance of location information. The zone structure is
formed virtually and the zone where a node is located can be          In Neighbor table generation every node will send a
                                                                   beacon message when it moves to a new zone . EGMP inserts




         Department of CSE, Sun College of Engineering and Technology
National Conference on Role of Cloud Computing Environment in Green Communication 2012
                                                                                                                                      202

a flag indicating whether the sender is leader or not in beacon       Geometric information can be used to more efficiently
message. On receiving the beacon from a neighbor, a node           construct and maintain multicast structure, and to achieve
records node ID, position and flag.                                more scalable and reliable multicast transmissions in the
                                                                   presence of constant topology change of MANET.Our
TABLE 1: The neighbor table of node 18 in Fig. 1.                  simulation results demonstrate that EGMP has high packet
                                                                   delivery ratio, and low control overhead and multicast group
nodeID    position     flag   zoneID                               joining delay under all cases studied, and is scalable to both
16        (x16,y16)    1      (1,1)                                the group size and the network size.Compared to the
1         (x1,y1)      0      (1,1)                                geographic multicast protocol SPBM, it has significantly
7         (x7,y7)      1      (0,1)                                lower control overhead, data transmission overhead, and
13        (x13,y13)    1      (1,2)                                multicast group joining delay.

                                                                                         V. REFERENCES
    A node check its neighbor table and determine its zone
leader under different strategies:
     no other nodes in the same zone.                             [1] M.Mauve, H.Fubler, J.Widmer,and T.Lang,” Position
     nodes in the same zone are unset.                                 based multicast routing for mobile Adhoc networks”. In
     more than one node in the same zone have their                    Poster section in ACM MOBIHOC, june 2003.
         leader flag set.                                          [2] C. Gui and P.Mohapatra.”Scalable Multicasting for
                                                                        Mobile     Adhoc       Networks”.      In    Proc     IEEE
     only one node in the zone with flag set.
                                                                        INFOCOM,Mar.2004.
C. Multicast Tree Construction                                     [3] V.Devarapalli and D.Sidhu.”MZR:A multicast protocol
   The multicast tree is constructed, all the sources of the            for    mobile     adhoc     networks”.In      ICC     2001
group could send packets to the tree and the packets will be            Proceedings,2001.
forwarded along the tree. In most tree-based multicast             [4] X.Xiang and X.Wang.”An Efficient Geographic
protocols, a data source needs to send the packets initially to         Multicast protocol for Mobile Adhoc Networks”.In IEEE
the root of the tree. The zone based multicast tree is                  International Symposium on a World of wireless,Mobile
constructed using the zone structure.This tree is shared for all        and      Multimedia       Networks(WoWMoM),Niagara-
multicast sources of a group. The tree supports bi-directional          Falls,Buffalo,New York,June 2006.
packetforwarding.                                                  [5] A.Ballardie.”Core based trees(CBT) multicast routing
                                                                        architecture”.In RFC 2201,September 1997.
D. Multicast Packet delivery                                       [6] X. Xiang and X. Wang. An Efficient Geographic
   The source node send packets to the tree and the packets             Multicast Protocol for Mobile Ad Hoc Networks. In
will be forwarded along the tree.The multicast packets can              IEEE International Symposium on a World of Wireless,
flow from upstream node to downstream node or vice versa.               Mobile and Multimedia Networks (WoWMoM),
After receiving the destination zone the packet will be                 Niagara-Falls, Buffalo, New York, June 2006.
forwarded to a specific receiving node or broadcast depend on      [7] S. Wu and K.S. Candan. GMP: Distributed Geographic
the message type.                                                       Multicast Routing in Wireless Sensor Networks. In Proc.
                                                                        26th IEEE Intl Conf. Distributed Computing Systems
                      IV. CONCLUSION                                    (ICDCS 06), 006.
                                                                   [8] T. Camp and Y. Liu, An adaptive mesh-based protocol
   There is an increasing demand and a big challenge to                 for geocast routing. In Journal of Parallel and Distributed
design more scalable and reliable multicast protocol over a             Computing, vvol. 63, no. 2, pp. 196213, 2003.
dynamic ad hoc network (MANET). An efficient and scalable           [9] S. Lee, W. Su, J. Hsu, M. Gerla, and R. Bagrodia. A
geographic multicast protocol, EGMP, for MANET. The                     performance comparison study of ad hoc wireless
scalability of EGMP is achieved through a two-tier virtual-             multicast protocols. In IEEE INFOCOM, 2000.
zone-based structure, which takes advantage of the geometric       [10] P. Bose, P. Morin, I. Stojmenovic and J. Urrutia. Routing
information to greatly simplify the zone management and                 with guaranteed delivery in ad hoc wireless networks. In
packet forwarding. A zone-based bi-directional multicast tree           Workshop on Discrete Algorithms and Methods for
is built at the upper tier for more efficient multicast                  Mobile Computing and Communications (DialM ´ 99),
membership management and data delivery, while the intra-               August 1999.
zone management is performed at the lower tier to realize the      [11] X. Xiang, Z. Zhou and X. Wang. Self-Adaptive On
local membership management. The position information is                Demand Geographic Routing Protocols for Mobile Ad
used in the protocol to guide the zone structure building,              Hoc Networks. IEEE INFOCOM07 minisymposium,
multicast tree construction, maintenance, and multicast packet          Anchorage, Alaska, May 2007.
forwarding. We also develop a scheme to handle the empty
zone problem, which is challenging for the zone-based
protocols.




         Department of CSE, Sun College of Engineering and Technology

				
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