A PERFORMANCE EVALUATION OF PROACTIVE AND REACTIVE PROTOCOLS USING NS2 SIMULATION

Document Sample
A  PERFORMANCE EVALUATION OF PROACTIVE AND REACTIVE PROTOCOLS  USING  NS2 SIMULATION Powered By Docstoc
					                                                                                 1




                                  `
          A PERFORMANCE EVALUATION OF PROACTIVE AND REACTIVE
                   PROTOCOLS USING NS2 SIMULATION


N.Karthikeyan1                    Dr.V.Palanisamy2            Dr.K.Duraiswamy3
               1
                   Research Scholar, Department of Computer Application,
          SNS College of Technology, Coimbatore-641035, Tamilnadu, India.
               Telephone: +91-422-2669118, Mobile: +91-98427 90907
                          E-Mail: kaartheekeyan@rediffmail.com
2
    Principal, Info Institute of Engineering, Sathy Main Road, Coimbatore-641107.
      3
          Dean, K.S.Rangasamy College of Technology, Tiruchengode – 637215


                                        Abstract

A mobile ad hoc network (MANET) is an infrastructure less, autonomous, and
standalone wireless network. The vision of mobile ad hoc network is to support
robust and efficient operation in mobile wireless networks by incorporating
routing functionality into mobile nodes. A mobile ad hoc network is the collection
of nodes which form the temporary network without the centralized body due to
constant changes in network topology. Each node in a MANET serves as a router
and performs mobility functionalities in an autonomous manner. Guaranteeing
delivery and the capability to handle dynamic connectivity are the most important
issues for routing protocols in mobile ad hoc networks. A number of routing
protocols have been proposed for this purpose like Ad Hoc On Demand Distance
Vector (AODV), Dynamic Source Routing (DSR) and Destination-Sequenced
                                                                                  2




Distance Vector(DSDV). In this paper the Reactive protocols DSR and AODV as
well as a Proactive Protocol DSDV were studied and their characteristics with
respect to different mobility are analyzed based on packet delivery fraction,
routing load, end-to-end delay, number of packets dropped, throughput and jitter
using Network Simulator (NS2) .

Keywords: MANET, Proactive and Reactive Routing Protocols

1. Introduction
In General, the network can be divided into two types based on their operation
namely infrastructure and infrastructure less. The infrastructure network (i.e. a
network with fixed and wired gateways) uses the fixed network topology and it
consists of nodes and base stations. The bridges of the network are known as base
stations. A mobile unit within the network connects the nearest base station for the
communication. In this infrastructure network, communication between nodes by
switching from one base station to another base station.

In infrastructure less network there are no such fixed infrastructures for nodes to
communicate with each other and each node acts as routers and cooperates with
other nodes for communication process. The Internet Engineering Task Force
created a MANET Working Group (WG) to deal with issues related to the
constructing MANET routing protocols. MANET [1] is a kind of wireless
network architecture that can be flexibly deployed in almost any environment
(e.g., conference rooms, forests, battlefields, disaster relief, vehicular services
such as transmission of news, road conditions, location award services, emergency
services, commercial environment, educational applications, entertainment, sensor
networks, home and enterprise networking etc.) without the need of network
infrastructure or centralized administration.

The fundamental difference between fixed networks and MANET is that the
computers in a MANET are mobile. Due to the mobility of these nodes, there are
some characteristics that are only applicable to MANET. Some of the key
                                                                                 3




characteristics are dynamic network topologies, bandwidth constrained links and
energy constrained operation. In real-time applications, such as audio, video, and
real-time data, the ad hoc networks need for Quality of Service (QoS) in terms of
delay, bandwidth, and packet loss is becoming important. Providing QoS in ad-
hoc networks is a challenging task because of dynamic nature of network
topology and imprecise state information. A mobile ad hoc network consists of
mobile nodes such as laptops, personal digital assistants and other devices which
use wireless connections for the purpose of communication. They have no fixed
routers and routes. All nodes are capable of moving and be connected in an
arbitrary manner. These nodes functions as routers, which discover and maintain
routes to other node in the network. The nodes are free to move around randomly,
thus changing the network topology dynamically. So the routing protocols must
be adaptive and be able to maintain routes in spite of changing network
connectivity.

In general routes between nodes in an ad hoc network may include multiple hops
and hence it is appropriate to call such networks as “multi-hop wireless ad-hoc
networks [2]”. Each node will be able to communicate directly with any other
node that resides within the transmission range. For communication with nodes
that reside beyond this range the node needs to use intermediate nodes to relay the
messages hop by hop. Ad hoc networks are useful in wide area of applications
such as military and other rescue application. Commercial applications are also
like where there is a need for ubiquitous communications without the presence of
fixed infrastructure.

2. Related Work
Several researchers have done the qualitative and quantitative analysis of Ad Hoc
Routing Protocols by means of different performance metrics. They have used
different simulators for this purpose.
                                                                               4




♦ Samir R. Das , Charles E. Perkins et al. [3] evaluated the DSR and AODV on-
demand routing protocols with three performance metrics : Packet delivery
fraction, Average End-to-End Delay and Normalized routing load with varying
pause times. They have used ns-2 simulator. Based on the observations,
recommendations were made as to how the performance of either protocol can be
improved.

♦ J. Broch et al. [4], in their paper have compared the DSDV, TORA, DSR and
AODV Protocols using ns-2 simulator. The simulation was done with 50 nodes
with varying pause times. The results were obtained for the metrics: Packet
delivery ratio, Routing overhead, Number of hops taken by the packet to reach the
destination.

♦ Jyoti Raju and Garcia-Luna-Aceves [5], in their paper have compared WRP-Lite
a revised version of Wireless Routing Protocol with DSR. The performance
parameters used are end-end delay, control overhead, percentage of packets
delivered and hop distribution. The evaluation of the performance metrics was
done with respect to varying pause time. It was observed that WRP-lite has much
better delay and hop performance while having comparable overhead to DSR.

♦ Samir R. Das et al. [6] evaluated the performance of routing protocols with
respect to fraction of packets delivered, end-to-end delay, and routing load by
varying the number of conversation per node. The evaluation was done with 30
and 60 nodes using Maryland Routing Simulator. The protocols used in the
simulation are SPF, DSDV, TORA, DSR, AODV.

♦ Azzedine Boukerche [7] , in his paper has done the performance comparison of
AODV,CBRP and DSR Ad Hoc routing protocols using ns-2 simulator. The key
performance metrics evaluated in his experiments are Throughput, Average End-
to-end delay of data packets and Normalized routing overhead for different data
sources and varying pause times of mobile nodes. As per his observation DSR and
                                                                                  5




CBRP has high throughput than in comparison with AODV.CBRP has high
routing overhead than DSR.

3. Types of MANET Routing Protocols

MANET routing protocols are mainly developed to maintain route inside
MANET, and they do not utilize access points to make connection with other
nodes in the infrastructure network and Internet. Routing protocols can be
classified into different categories depending on their properties. The
classifications are

            Centralized versus Distributed

            Static versus Adaptive

            Reactive versus Proactive

One way to categorize the routing protocols is to divide them into centralized and
distributed algorithms. In centralized algorithms, all route choices are made at a
central node, while in distributed algorithms, the computation of routes is shared
among the network nodes. In static algorithms, the route used by source
destination pairs is fixed regardless of traffic condition. It can only change in
response to a node or link failure. This type of algorithm cannot achieve high
throughput under a broad variety of traffic input patterns. In adaptive routing, the
routes used to route between source-destination pairs may change in response to
congestion. A third classification that is more related to ad-hoc networks is to
classify the routing algorithms as either proactive or reactive.

3.1 Proactive (Table-Driven) Routing Protocols

It maintain one or more routing tables in every node in order to store routing
information about other nodes in the MANET. These routing protocols attempt to
update the routing tables information either periodically or in response to change
in network topology in order to maintain consistent and up-to-date routing
                                                                                  6




information. The advantage of these protocols is that a source node does not need
a route-discovery procedures to find a route to a destination node. The drawback
of these protocols is that maintaining a consistent and up-to-date routing table
requires substantial messaging overhead, which consumes bandwidth and power
uage, and decreases throughput, especially in the case of a large number of high-
mobility mobile nodes. The different types of Table driven protocols are:
Destination Sequeced Distance Vector routing(DSDV), Wireless routing protocol
(WRP), Fish eye State Routing protocol (FSR), Optimised Link State Routing
protocol (OLSR), Cluster Gateway switch routing protocol (CGSR), Topology
Dissemination Based on Reverse path forwarding (TBRPF).

3.2 Reactive (On-Demand) Routing Protocols

It initiate a route discovery mechanism by the source node to discover the route to
the destination node when the source node has data packets to send to the
destination node. After discovering the route, the route maintenance is initiated to
maintain this route until the routes no longer required or the destination is not
reachable.The main advantage of these protocols is that overhead messaging is
less. One of the drawbacks of these protocols is the delay of discovering a new
route. The different types of Reactive routing protocols are : Dynamic Source
Routing (DSR) , Ad hoc On-Demand Distance Vector routing (AODV) and
Temporally Ordered Routing Algorithm(TORA).

3.3 Dynamic Source Routing (DSR)

The Dynamic Source Routing protocol (DSR) [8] is a simple and efficient routing
protocol designed specifically for use in multi-hop wireless ad hoc networks of
mobile nodes. Using DSR, the network is completely self-organizing and self-
configuring, requiring no existing network infrastructure or administration.
Network nodes cooperate to forward packets for each other to allow
communication over multiple "hops" between nodes not directly within wireless
transmission range of one another. The DSR protocol is composed of two main
                                                                                      7




mechanisms that work together to allow the discovery and maintenance of source
routes in the ad hoc network.Route Discovery is the mechanism by which a node
S wishing to send a packet to a destination node D obtains a source route to D.
Route Discovery is used only when S attempts to send a packet to D and does not
already know a route to D. Route Maintenance is the mechanism by which node S
is able to detect, while using a source route to D, if the network topology has
changed such that it can no longer use its route to D because a link along the route
no longer works. When Route Maintenance indicates a source route is broken, S
can attempt to use any other route it happens to know to D, or it can invoke Route
Discovery again to find a new route for subsequent packets to D. When a node
requires a route to a destination, which it doesn’t have in its route cache, it
broadcasts a Route Request (RREQ) message, which is flooded throughout the
network. The first RREQ message is a broadcast query on neighbors without
flooding. Each RREQ packet is uniquely identified by the initiator’s address and
the request id. A node processes a route request packet only if it has not already
seen the packet and its address is not present in the route record of the packet.

This minimizes the number of route requests propagated in the network. RREQ is
replied by the destination node or an intermediate node, which knows the route,
using the Route Reply (RREP) message. The return route for the RREP message
may be one of the routes that exist in the route cache (if it exists) or a list reversal
of the nodes in the RREQ packet if symmetrical routing is supported. In other
cases the node may initiate it owns route discovery mechanism and piggyback the
RREP packet onto it. Thus the route may be considered unidirectional or
bidirectional. DSR doesn’t enforce any use of periodic messages from the mobile
hosts for maintenance of routes. There are two types of packets for route
maintenance: Route Error (RERR) packets and ACKs. Whenever a node
encounters fatal transmission errors so that the route becomes invalid, the source
receives a RERR message. The source node then removes the erroneous hop from
all of its route cache entries, and selects a new route, or if there are no more
                                                                                    8




available routes, it initiates a new route discovery. ACK packets are used to verify
the correct operation of the route links. This also serves as a passive
acknowledgement for the mobile node.

3.4 Ad-hoc On Demand Distance Vector (AODV)
The AODV [9,10] routing protocol is a reactive routing protocol; therefore, routes
are determined only when needed. The following messages are used in AODV
protocol: Hello message, Route Request(RREQ) message, Route Reply(RREP),
and Route Error(RERR) message. Hello messages may be used to detect and
monitor links to neighbors. If Hello messages are used, each active node
periodically broadcasts a Hello message that all its neighbors receive. Because
nodes periodically send Hello messages, if a node fails to receive several Hello
messages from a neighbor, a link break is detected. When a source has data to
transmit to an unknown destination, it broadcasts a Route Request (RREQ) for
that destination. At each intermediate node, when a RREQ is received a route to
the source is created. If the receiving node has not received this RREQ before, is
not the destination and does not have a current route to the destination, it
rebroadcasts the RREQ. If the receiving node is the destination or has a current
route to the destination, it generates a Route Reply (RREP). The RREP is unicast
in a hop-by-hop fashion to the source. As the RREP propagates, each intermediate
node creates a route to the destination. When the source receives the RREP, it
records the route to the destination and can begin sending data. If multiple RREPs
are received by the source, the route with the shortest hop count is chosen. As data
flows from the source to the destination, each node along the route updates the
timers associated with the routes to the source and destination, maintaining the
routes in the routing table. If a route is not used for some period of time, a node
cannot be sure whether the route is still valid; consequently, the node removes the
route from its routing table. If data is flowing and a link break is detected, a Route
Error (RERR) is sent to the source of the data in a hop-by-hop fashion. As the
RERR propagates towards the source, each intermediate node invalidates routes to
                                                                                    9




any unreachable destinations. When the source of the data receives the RERR, it
invalidates the route and reinitiates route discovery if necessary.
3.5 Destination Sequenced Distance Vector(DSDV)
DSDV [11] is a Table driven routing protocol based on the classical Bellman-Ford
routing algorithm. The improvement made to the Bellman-Ford algorithm
includes freedom from loops in routing tables by using sequence numbers. In this
routing protocol, each mobile node in the system maintains a routing table in
which all the possible destinations and the number of hops to them in the network
are recorded. A sequence number is also associated with each route/path to the
destination. The route labeled with the highest sequence number is always used.
This also helps in identifying the stale routes from the new ones, thereby avoiding
the formation of loops. Also, to minimize the traffic generated, there are two types
of packets in the system. One is known as “full dump”, which is a packet that
carries all the information about a change. However, at the time of occasional
movement, another type of packet called “incremental” will be used, which will
carry just the changes, thereby, increasing the overall efficiency of the system.

The data broadcast by each mobile node will contain the new sequence number,
the destination’s address, the number of hops to reach the destination and the
sequence number of the information received regarding that destination. Each
node advertises an increasing even sequence number for itself. When Node A
determines that destination Node D is unreachable, it advertises the next odd
sequence number for the route that has failed with an infinite metric count. Any
node that receives this infinite metric count updates its table for the matching
route and waits until a greater sequence number with non-infinite metric count is
received. Every mobile host also calculates the weighted average of the time taken
to receive a route with the best metric. This time is called as settling time. A
comparison of the characteristics of the above three ad hoc routing protocols
DSDV, DSR, AODV is given in Table 1.
                                                                                       10




                          Table 1: Ad hoc network protocol comparisons


   PROTOCOL PROPERTY                    DSR                      DSDV          AODV

    Loop Free                           Yes                      Yes           Yes

   Multicast Routes                     Yes                      No            No

   Distributed                          Yes                      Yes           Yes

   Unidirectional Link Support          Yes                      No            No

   Multicast                            No                       No            Yes

   Periodic Broadcast                   No                       Yes           Yes

   QoS Support                          No                       No            No

                                                                               Route
   Routes Maintained in                 Route Cache              Route Table
                                                                               Table

   Reactive                             Yes                      No            Yes



4 Performance Metrics of Routing Protocols

In order to evaluate the performance of ad hoc network routing protocols, the
following metrics were considered:

End-to-End Delay: The average time interval between the generation of a packet
in a source node and the successfully delivery of the packet at the destination
node. It counts all possible delays that can occur in the source and all intermediate
nodes, including queuing time, packet transmission and propagation, and
retransmissions at the MAC layer. The queuing time can be caused by network
congestion or unavailability of valid routes.
                                                                                 11




Packet Delivery Fraction: The ratio of the number of data packets successfully
delivered to all destination nodes and the number of data packets generated by all
source nodes.

Routing Load: The ratio of the number of routing messages propagated by every
node in the network and the number of data packets successfully delivered to all
destination nodes. In other words, the routing load means the average number of
routing messages generated to each data packet successfully delivered to the
destination.

Number of Packets dropped: The number of data packets that are not
successfully sent to the destination during the transmission.

Jitter: Jitter describes standard deviation of packet delay between all nodes.

Throughput: The throughput metric measures how well the network can
constantly provide data to the sink. Throughput is the number of packet arriving at
the sink per ms.

Power consumption: The total consumed energy divided by the number of
delivered packet.

4.1 Simulation Environment

There are two approaches used to evaluate routing protocols: using simulation or
performing experiments on real time. In both cases, the performance metrics as
well as the network context are equally important. In this work, the characteristics
and behavior of the AODV, DSV and DSDV routing protocols especially in the
initial condition of the communication between nodes for a very short duration.
During the initial condition, the routing protocols will behave varyingly due to the
differences in the mechanism of route discovery. The route discovery process will
be affected by the mobility of each and every nodes of the network. So during the
initial phase of communication, the behavior of the routing protocol and the
                                                                                   12




characteristics of communication will significantly differ from normal conditions.
The scope of the study is to measure such characteristics during the initial
condition of the network.

4.2 Simulation set-up
Comparing with the commercial software OPNET, NS2 has an advantage.
Network Simulator (NS2) is a discrete event simulator targeted at networking
research [12]. NS2 provides substantial support for simulation of TCP, routing,
and multicast protocols over wired and wireless (local and satellite) networks. The
proposed system has been successfully implemented and evaluated using Network
Simulator 2. In order to create the different traffic scenarios files we need to go to
the cmu-scen-gen directory and the path is ns/ns-2.31/inde-utils/cmu-scen-gen.
Here we can find a traffic generator script ns.cbrgen.tcl. By using this script we
can create the different traffic scenario files, by selecting the TCP or CBR
connections between nodes. The mobility models can be generated by using the
directory. /setdest, we can go to that directory by setting the path ns2/ns-
2.31/indep-utils/cmu-scen-gen/setdest.

The following simulation parameters have taken for the simulation.

   Number of Nodes                     20
  Number of Sending Nodes              10
  The Pause Time                       0, 10, 20, 30&40(sec)
  Routing Protocol                     DSDV/AODV/DSR
  The Maximum Node Speed               20m/s
  Topography                           x=500 y=500
  Propagation                          Two Ray Ground
  Antenna Type                         Omni Antenna
The table below shows the performance of the routing protocols DSDV, AODV,
and DSR with respect to different metrics considered above.
                                                                                                               13




Destination Sequence Distance Vector:

                        Table 2: DSDV Performance with different metrics




                                                                                         Throughput
                         Normalized




                                               End to End
                                               Delay (ms)
   Time(sec)




                                                               Dropped
                         Routing




                                                               Packets
   Pause




                                                                                                           Jitter
                                                               Total
                         Load
               PDF




        0      74.7           1.69                8.72              1375             76.88                 3.98

       10      78.9           1.67                9.94              1137             80.73                 5.43

       20      71.1           1.89               10.56              1613             72.94                 5.91

       30      70.0           2.28               12.86              1672             72.61                 9.85

       40      78.4            1.8               10.28              1170             80.11                 5.56




Ad hoc On Demand Distance Vector:

                        Table 3: AODV Performance with different metrics
                                                                            Throughput
                           Normalized




                                              End to End
                                              Delay (ms)
  Time(sec)




                                                            Dropped
                           Routing




                                                            Packets
  Pause




                                                                                                      Jitter
                                                            Total
                           Load
                 PDF




       0        99.25           1.88            12.3              42       102.09                     7.03

      10        99.56           1.8            11.72              24       102.26                     6.05

      20        99.15           2.16           14.87              52       102.12                     9.07

      30        99.23           2.1            14.28              48       103.31                     7.96

      40        99.46           1.87           15.76              27       103.25                     12.3
                                                                                                                14




Dynamic Source Routing:

                                 Table 4: DSR Performance with different metrics




                                                    End to End




                                                                                       Throughput
                            Normalized




                                                    Delay (ms)
    Time(ms)




                                                                      Dropped
                            Routing




                                                                      Packets
    Pause




                                                                                                       Jitter
                                                                      Total
                            Load
                 PDF




0              99.29     1.5                    11.44                 84           102.24           7.53

10             100       1.51                   12.95                 41           103.2            11.54

20             99.69     1.72                   23.77                 111          102.27           32.14

30             99.22     1.83                   15.18                 96           101.82           12.53

40             99.93     1.69                   13.82                 46           102.54           11.49




4.3 Performance results of AODV, DSR and DSDV
The graphs below shows the performance of the routing protocol with respect to
different metric considered above. The X- Axis shows the pause times of the
nodes and the y axis shows the Metric considered for simulation


                                               Pause-Time vs PDF

                                 120

                                 100

                                  80
                                                                                DSDV
                           PDF




                                  60                                            AODV
                                                                                DSR
                                  40

                                  20

                                   0
                                        0      10       20       30        40
                                                    Pause-Time




                       Figure. 1 Packet Delivery fraction for AODV, DSR and DSDV
                                                                                                                    15




In terms of PDF with respect to varied pause time, DSR performs well when the
number of nodes is less, which is shown in Fig.1. The performance of AODV is
consistently uniform and DSDV performance is poor than reactive protocols.


                                                                   Pause-Time vs Routing Load

                                                   2.5
                         Normalised Routing Load


                                                       2

                                                   1.5                                                      DSDV
                                                                                                            AODV
                                                       1                                                    DSR

                                                   0.5

                                                       0
                                                               0      10        20         30         40
                                                                           Pause-Time



                    Figure. 2 Packet Routing load for AODV, DSR and DSDV

In terms of Routing Load with respect to varied pause time, DSR is found to be
less when compared to AODV and DSDV because of DSR aggressive caching
techniques, which is observed in Fig.2 .


                                                                     Pause-Time vs End to End Delay

                                              25
                      End to End Delay (ms)




                                              20

                                              15                                                             DSDV
                                                                                                             AODV
                                              10                                                             DSR

                                                   5

                                                   0
                                                           0         10         20          30         40
                                                                            Pause-Time

                     Figure. 3 End-to-End delay for AODV, DSR and DSDV

In terms of end-to-end delay, DSDV is the best performer. As routing information
is constantly updated in the proactive protocols, routes to every destination are
always available and up-to-date, and hence end-to-end delay can be minimized as
shown in Fig.3
                                                                                                                          16




                                                                        Pause-Time vs Total Dropped Packets

                                                       1800

                                                       1600




                           Number of Dropped Packets
                                                       1400

                                                       1200
                                                                                                                   DSDV
                                                       1000
                                                                                                                   AODV
                                                       800                                                         DSR
                                                       600

                                                       400

                                                       200

                                                            0
                                                                    0     10         20         30            40
                                                                                 Pause-Time




                     Figure. 4. Packets dropped for AODV,DSR and DSDV


In terms of packets dropping, DSDV performance is worst when mobility is high.
This is because of the reason that it keeps only one route per destination.
Therefore lack of alternate routes and presence of stale routes in routing table
when nodes are moving at higher rate leads to packet drops, which is shown in
Fig.4


                                                                        Pause-Time vs Average Throughput

                                                   120

                                                   100

                                                       80
                      Throughput




                                                                                                                   DSDV
                                                       60                                                          AODV
                                                                                                                   DSR
                                                       40

                                                       20

                                                        0
                                                                0        10         20         30          40
                                                                               Pause-Time




                    Figure..5. Average throughput for AODV,DSR and DSDV


In Figure.5, with respect to varied pause time, throughput decreases
comparatively in DSDV as it needs to advertise periodic updates and even-driven
updates. If the node mobility is high then occurrence of even driven updates are
more.
                                                                                  17




                                               Pause-Time vs Jitter
                                 35

                                 30

                                 25

                                 20
                        Jitter

                                                                           DSDV
                                 15                                        AODV
                                                                           DSR
                                 10

                                 5

                                 0
                                      0   10          20        30    40
                                                 Pause-Time




                      Figure.6. Jitter performance for AODV,DSR and DSDV


With regard to jitter, DSDV and AODV showed the best average performance
than DSR. Jitter is determined by calculating the standard deviation of the latency
as shown in Fig. 6.




                       Figure.7. Power efficiency for AODV,DSR and DSDV


In terms of Power efficiency, DSDV is the best performer than reactive protocols.
AODV consumes much power while comparing with the other two, which is
observed in Fig. 7.
                                                                             18




                    Figure.8. Throughput Vs Time for AODV,DSR and DSDV


With regard to throughput versus time, DSR consumes considerable power and
gives lower throughput due to network failure, which is shown in Fig. 8. (Since
we started the simulation with very low battery power)


Discussion and Conclusion

In this paper, we have examined simulation studies and also compared the On-
Demand (DSR and AODV) and Table-Driven (DSDV) routing protocols by
varying the pause time and measured the metrics like end-end delay, dropped
packets, routing overhead, power efficiency etc. The results indicate that the
performance of the two on demand protocols namely DSR and AODV is superior
to the DSDV in conformance with the work done by other researchers as
mentioned in section 2. It is also observed that DSR outperforms AODV in less
stressful situations, i.e smaller number of nodes. AODV outperforms DSR in
more stressful situations. The poor delay and packet delivery ratio of DSR is
mainly due to caching and lack of mechanisms to expire stale routes. The routing
overhead is consistently low for DSR and AODV than in comparison with DSDV
                                                                              19




especially for large number of nodes. This is due to the fact that in DSDV the
routing table exchanges would increase with larger number of nodes. The results
indicate that as the number of nodes in the network increases DSDV would be
better with regard to the packet delivery ratio, but it may have considerable
routing overhead. As far as packet delay and dropped packets ratio are concerned,
DSR/AODV performs better than DSDV with large number of nodes. Hence for
real time traffic AODV is preferred over DSR and DSDV. For less number of
nodes and less mobility, DSDV’s performance is superior. The metric of Power
efficiency concerns, the result indicates that DSDV is best performer. As far as
throughput versus time concern, DSR consumes considerable power and gives
lower consumption due to network failure.

Acknowledgments

The authors would like to thank Dr.S.N.Subbramanian, Director cum Secretary,
Dr.S.Rajalakshmi, Correspondent, Dr.V.P.Arunachalam, Principal, SNS College
of Technology, Coimbatore for their motivation and constant encouragement. The
author would like to thank Supervisor Dr.V.Palanisamy, Principal, Info Institute
of Engineering and Joint Supervisor Dr.K.Duraiswamy, Dean, KSR College of
Technology for their valuable input and fruitful discussions.

References

[1] C.Perkins, Ad Hoc Networking, New York: Addison Wesley, 2000

[2] S.Corson and J.Macker, Mobile Ad hoc Networking: Routing Protocol
      Performance issues and Evaluation Considerations, RFC 2501, January 1999.

[3]   S.R. Das, C.E. Perkins, and E.E. Royer, “Performance Comparison of Two
      On-Demand Routing Protocols for Ad Hoc        Networks,” Proc. INFOCOM,
      2000, pp.3- 12.
                                                                               20




[4] J. Broch, D. A. Maltz, D. B. Johnson, Y-C. Hu, and J.Jetcheva, “A
      performance comparison of multi-hop       wireless ad hoc network routing
      protocols”, Mobicom’ 98, October 1998, pages 85-97.

[5]    J. Raju and J.Garcia-Luna-Aceves, "A comparison of on-demand and table
      driven routing for ad-hoc wireless networks",     Proc. of IEEE ICC, June -
      2000, pages   1702- 1706.

[6] S.R. Das, R. Castaneda, J. Yan, and R. Sengupta, “Comparative performance
      evaluation of routing protocols for mobile ad hoc networks”, 7th Int. Conf.
      on Computer Communications and Networks (IC3N), October 1998, pages
      153–161.

[7] Boukerche A., “Performance comparison and analysis of           ad hoc routing
      algorithms”, IEEE International Conference on. Performance, Computing,
      and Communications, 2001, Apr 2001, pp 171-178.

[8] D. Johnson, Y. Hu, D. Maltz, “The Dynamic Source Routing Protocol (DSR)
      for Mobile Ad Hoc Networks for IPv4” RFC 4728 February 2007

[9] C. E. Perkins, E. M. Belding-Royer, and S. Das. Ad hoc On-Demand
      Distance Vector (AODV) Routing. RFC 3561, July 2003.

[10] C. E. Perkins and E. M. Royer. The Ad hoc On-Demand Distance Vector
      Protocol.   In C. E. Perkins,   editor, Ad hoc   Networking, pages 173–219.
      Addison- Wesley, 2000.

[11] C.E. Perkins and P. Bhagwat, “Highly Dynamic            Destination-Sequenced
      Distance-Vector Routing (DSDV) for Mobile Computers,” Proc. ACM
      SIGCOMM ’94, pp. 234-244, 1994.

[12]Marc      Greis.     NS2      Tutorial    presentation    in    the    website
      www.isi.edu/nsnam/ns/tutorial/nsindex.html

				
DOCUMENT INFO
Shared By:
Tags:
Stats:
views:349
posted:12/14/2010
language:English
pages:20
About Working as a professor