IJRSAT Issue 1-Volume 3-QoS based Delay-Constrained AODV Routing in MANET by admin1849


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									                 BHANU* et al.
                 ISSUE-1, VOLUME-3, 096-099

     QoS based Delay-Constrained AODV Routing in
                                          Mr. Bhanu Pratap Singh1, Mr. Mubeen Khan2
                            M.Tech Scholar, Medicaps Institute of Technology & Management, Indore, India
                            M.Tech Scholar, Medicaps Institute of Technology & Management, Indore, India

Abstract- MANET (Mobile Ad-hoc Network) is a self                    a network and the number of hops to each destination and
organizing and self configuring network without the                  save them in their routing tables. New route broadcasts
need of any centralized base station. The nodes of mobile            contain the address of destination, the number of hops to reach
ad-hoc network are mobile and battery constrained. As the            the destination, the sequence number of the information
nodes have limited battery resources and multi hop routes are
                                                                     receive regarding the destination, as well as a new unique
used over a changing network environment due to node mobility,
it requires energy efficient routing protocols to limit the          sequence number for the new route broadcast [2]. In this
power consumption, prolong the battery life and to                   paper a new scheme used that is Energy efficient routing, it
improve the robustness of the system. These limitations result       deals with efficient utilization of energy resources. By
long processing delays in a relay/forwarding node. In order to       controlling the early depletion of the battery, adjust the power
alleviate these issues, we propose a solution based on cross-layer   to decide the proper power level of a node and incorporate the
MAC design, which improves the coordination between MAC              low power strategies into the protocols used in various layers
and routing layers using an idea we call “virtual link". The
                                                                     of protocol stack. There are little issues and solutions which
virtual link idea was implemented         and tested in an ad hoc
wireless network. This paper evaluates the performance of            witnesses the need of energy aware routing in ad hoc wireless
various ad-hoc routing protocols such as DSDV, AODV,                 networks.
DSR, TORA and AOMDV in terms of energy efficiency                    The paper organization is as follows: related work is described
and it also proposes a new routing                algorithm that     in section 2. Routing protocol and AODV routing is described
modifies AOMDV             and it provides better performance        in section 3 and proposed scheme is described in section 4 and
compared to all the above protocols. Simulation is done using        5.Network simulation results are presented in section 6
NS-2(version NS -2.34).                                              followed by conclusions and future work in section 7.
Keywords— MANET, Energy Efficiency, Routing, AODV,
Urgent Packets.                                                                            II. RELATED WORK
                       I. INTRODUCTION                               Routing in Mobile Ad hoc Networks:-Mobile Ad-hoc
A Mobile Ad-hoc Network (MANET) is a collection of                   networks are self-organizing and self-configuring multihop
wireless nodes that can dynamically set up anywhere without          wireless networks, where the structure of the network changes
using pre-specified network infrastructure. It is an                 dynamically. This is mainly due to the mobility of the nodes
autonomous system in which mobile hosts connected by                 [3]. Nodes in these networks utilize the same random access
wireless links are free to move anywhere in the network. The         wireless channel, cooperating in an intimate manner to
topology of such networks is dynamic in nature. Due to the           engaging themselves in multihop forwarding. The node in the
limited wireless transmission range several intermediate nodes       network not only acts as hosts but also as routers that route
can be used. Route establishment is done with a minimum              data to/from other nodes in network. In mobile ad-hoc
overhead and bandwidth consumption. AODV is perhaps the              networks there is no infrastructure support as is the case with
most well-known routing protocol for MANET [1], which is a           wireless networks, and since a destination node might be out
hop-by-hop reactive (On demand) source routing protocol,             of range of a source node transferring packets; so there is need
combines DSR and DSDV mechanisms for routing, by using               of a routing procedure. This is always ready to find a path so
the on-demand mechanism of routing discovery and route               as to forward the packets appropriately between the source
maintenance from DSR and the hop-by-hop routing and                  and the destination. Within a cell, a base station can reach all
sequence number from DSDV. For each destination, AODV                mobile nodes without routing via broadcast in common
creates a routing table like DSDV [2]. It offers quick               wireless networks. In the case of ad-hoc networks, each node
adaptation to dynamic link conditions, low processing and            must be able to forward data for other nodes. This creates
memory overhead, low network utilization, and determines             additional problems along with the problems of dynamic
unicast routes to destinations within the Ad-hoc network             topology which is unpredictable connectivity changes.
[1].Destination-Sequenced Distance Vector (DSDV) routing             Properties of Ad-Hoc Routing protocols
protocol is a typical routing protocol for MANETs, which is
based on the Distributed Bellman-Ford algorithm [3]. In              The properties of Ad-Hoc Routing protocols are [4]:
DSDV, each route is tagged with a sequence number which is           i). Distributed operation: The protocol should be distributed. It
originated by destination, indicating how old the route is [2].      should not be dependent on a centralized controlling node.
All nodes try to find all paths to possible destinations nodes in

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This is the case even for stationary networks. The dissimilarity    each destination. Many routing protocols including
is that the nodes in an ad-hoc network can enter or leave the       Destination-Sequenced Distance Vector (DSDV) [5] and
network very easily and because of mobility the network can         Fisheye State Routing (FSR) protocol [6] belong to this
be partitioned.                                                     category, and they differ in the number of routing tables
                                                                    manipulated and the methods used to exchange and maintain
ii). Loop free: To improve the overall performance, the
                                                                    routing tables. With on-demand driven routing, routes are
routing protocol should assurance that the routes supplied are
                                                                    discovered only when a source node desires them. Route
loop free. This avoids any misuse of bandwidth or CPU
                                                                    discovery and route maintenance are two main procedures:
                                                                    The route discovery process involves sending route-request
iii). Demand based operation: To minimize the control               packets from a source to its neighbour nodes, which then
overhead in the network and thus not misuse the network             forward the request to their neighbours, and so on. Once the
resources the protocol should be reactive. This means that the      route-request reaches the destination node, it responds by
protocol should react only when needed and should not               uncasing a route-reply packet back to the source node via the
periodically broadcast control information.                         neighbour from which it first received the route-request.
                                                                    When the route-request reaches an intermediate node that has
iv). Quality of Service Support: Some sort of Quality of            a sufficiently up-to-date route, it stops forwarding and sends a
service is necessary to incorporate into the routing protocol.      route-reply message back to the source. Once the route is
This helps to find what these networks will be used for. It
                                                                    established, some form of route maintenance process
could be for instance real time traffic support.
                                                                    maintains it in each node’s internal data structure called a
Problems in routing with Mobile Ad hoc Networks                     route-cache until the destination becomes inaccessible along
                                                                    the route. Note that each node learns the routing paths as time
i). Asymmetric links: Most of the wired networks rely on the        passes not only as a source or an intermediate node but also as
symmetric links which are always fixed. But this is not a case      an overhearing neighbour node. In contrast to table-driven
with ad-hoc networks as the nodes are mobile and constantly         routing protocols, not all up-to-date routes are maintained at
changing their position within network                              every node. Dynamic Source Routing (DSR) [7] and Ad-Hoc
ii). Routing Overhead: In wireless ad hoc networks, nodes           On-Demand Distance Vector (AODV) [8] are examples of on-
often change their location within network. So, some stale          demand driven protocols. In proposed simulation we use the
routes are generated in the routing table which leads to            reactive AODV routing protocol because this is on demand
unnecessary routing overhead.                                       routing protocol. No routing table will created by that over
                                                                    head in the network reduces and efficient then table
iii). Interference: This is the major problem with mobile ad-       driven/proactive routing protocol.
hoc networks as links come and go depending on the
transmission characteristics, one transmission might interfere                       III. AODV ROUTING PROTOCOL
with another one and node might overhear transmissions of           In this section we describe the routing process of normal
other nodes and can corrupt the total transmission.                 AODV routing protocol [9]. It does not maintain routes from
iv). Dynamic Topology: Since the topology is not constant; so       every node to every other node in the network rather they are
the mobile node might move or medium characteristics might          discovered as and when needed & are maintained only as long
change. In ad-hoc networks, routing tables must somehow             as they are required. The key steps of algorithm used by
reflect these changes in topology and routing algorithms have       AODV for establishment of uncast routes are explained
to be adapted. For example in a fixed network routing table         below.
updating takes place for every 30sec. This updating frequency       A. Route Discovery
might be very low for ad-hoc networks. Routing Protocol for         When a node wants to send a data packet to a destination
MANET                                                               node, the entries in route table are checked to ensure whether
                                                                    there is a current route to that destination node or not. If it is
The routing protocols proposed for MANETs are generally             there, the data packet is forwarded to the appropriate next hop
categorized as table-driven and on-demand driven based on           toward the destination. If it is not there, the route discovery
the timing of when the routes are updated. With table-driven        process is initiated. AODV initiates a route discovery process
routing protocols, each node attempts to maintain consistent,       using Route Request (RREQ) and Route Reply (RREP). The
up-to-date routing information to every other node in the           source node will create a RREQ packet containing its IP
network. This is done in response to changes in the network         address, its current sequence number, the destination’s IP
by having each node update its routing table and propagate the      address, the destination’s last sequence number and broadcast
updates to its neighbouring nodes. Thus, it is proactive in the     ID. The broadcast ID is incremented each time the source
sense that when a packet needs to be forwarded the route is         node initiates RREQ. Basically, the sequence numbers are
already known and can be immediately used. As is the case           used to determine the timeliness of each data packet and the
for wired networks, the routing table is constructed using          broadcast ID & the IP address together form a unique
either link-state or distance vector algorithms containing a list   identifier for RREQ so as to uniquely identify each request.
of all the destinations, the next hop, and the number of hops to    The requests are sent using RREQ message and the

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information in connection with creation of a route is sent back    The simulation described in this paper was tested using the ns-
in RREP message. The source node broadcasts the RREQ               2 test-bed that allows users to create arbitrary network
packet to its neighbours and then sets a timer to wait for a       topologies [11]. By changing the logical topology of the
reply. To process the RREQ, the node sets up a reverse route       network, ns-2 users can conduct tests in an ad hoc network
entry for the source node in its route table. This helps to know   without having to physically move the nodes. Ns-2 controls
how to forward a RREP to the source. Basically a lifetime is       the test scenarios through a wireless interface, while the ad
associated with the reverse route entry and if this entry is not   hoc nodes communicate through a wireless interface. Here we
used within this lifetime, the route information is deleted. If    are taking the some essential simulation parameters. The
the RREQ is lost during transmission, the source node is           results are calculated on the basis of these parameters [12].
allowed to broadcast again using route discovery mechanism                                     TABLE I
[10].                                                                            SIMULATION PARAMETERS FOR CASE STUDY

                     IV. PROPOSED SCHEME                              Number of nodes                            8
Ad hoc wireless networks are power constrained since nodes            Dimension of simulated area                800×600
operate with limited battery energy. If some nodes die early          Initial node energy ( joules)              100
due to lack of energy, they cannot communicate with each              Threshold value(joule)                     20
other. Therefore, inordinate consumption of nodes’ energy             Minimum threshold value(joule)             1
should be prevented. In fact, nodes residual energy utilization       Simulation time (min)                      100
after threshold should be increase the energy utilization of          Radio range                                250m
networks. Here we proposed a new energy utilization scheme
                                                                      Traffic type                               CBR, 3pkts/s
in MANET which reduces delay and utilizes remaining
                                                                      Packet size (bytes)                        512
energy. In this scheme we set a threshold value for energy
consumption by mobile nodes in our network. If the energy             Maximum Speed (m/s)                        35
level of any node/s in the network reaches to threshold level         Node movement                              random
that are participated in communication means it will be active        Tx energy consumption                      1.5J
in the network. But here we apply one condition, number of            Rx energy consumption                      1.0J
nodes that having a energy remaining after threshold value is         Idle energy consumption                    0.017J
also utilized in communication. According to our proposed             Sleeping energy consumption                0.001J
approach a new energy aware efficient routing to make aware
our network about the energy of nodes by that we remove the        A. Scenario for Connection Establishment
problem of suddenly loss of session to recognize the               Here we show the snap shot of eight nodes they are sensing
unfaithful nodes and extend the life cycle of network.             the neighbour for establish connection between the source
                                                                   nodes to destination node through intermediate nodes. In this
        V. PROPOSED SCHEME BASED AODV ROUTING                      scenario the yellow colour nodes are having a sufficient
Now based on this scheme AODV generate a RREQ message              energy for communication.
to their neighbours if node energy is greater than threshold
value then establish connection and forwarded request up to
destination. Then all the nodes send back the RREP message
to their sender according to energy condition criteria.
The numbers of nodes in the network are only take part in
communication if they have a sufficient energy except the
urgent packet condition.
From a functional point of view, proposed algorithm can be
considered to consist of two main units. One of these units
handles the energy conservation operation. This is done
through managing the nodes’ energy level periods. The other
unit or aspect of the algorithm takes care of supporting the
routing protocol, as far as energy management decisions are
concerned. It helps to ensure the routing protocol makes
routing decisions that serve a specific goal. For example,
whenever possible, nodes carry out routing duties that are
proportional to their energy levels compared to each other.
Figure-1 shows the interactions of algorithm with the network
and MAC/PHY layers.

                                                                       Figure 1Nodes are sensing their neighbour to establish connection.

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                                                                        this work. After execution tcl script, .tr (TRACE) files
                                                                        and .nam (NAM) files have been generated and
                                                                        simultaneously packets movement between the nodes in NAM
                                                                        (network animator) has been visualized. In this paper, AODV
B. Packet Delivery Ratio Comparison                                     routing protocol using different parameter of QoS metrics
With the help of AWK tool, we have obtained this graph. If              have been simulated and analyzed.
packet delivery ratio is higher it means our performance is             A proposed scheme has been utilizes power status of each
best.                                                                   mobile node and alternate paths. This scheme will give best
                                                                        result in the network where no of nodes are more (>50). This
                                                                        scheme can be incorporated into any ad hoc on-demand
                                                                        routing protocol to improve reliable packet delivery in the
                                                                        face of node movements and route breaks. Alternate routes are
                                                                        utilized only when data packets cannot be delivered through
                                                                        the primary route
                                                                        In future we apply our concept with all different MANET
                                                                        protocol like DSR, DSDV and OLSR. In future we also use
                                                                        various energy depletion parameters and simulate our work so
                                                                        in future rectified result get from our proposed module.

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       Figure 2 Scenario of TCP Analysis based on previous Energy

The entire simulations were carried out using ns 2.31 network
simulator which is a discrete event driven simulator developed
at UC Berkeley as a part of the VINT project. By using
CYGWIN command shell has been executed successfully in

   Nov-Dec 2012 Edition
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