Simulation and Analysis of Ad hoc On dem

Simulation and Analysis of Ad-hoc On-demand Distance
Vector Routing Protocol
Md. Monzur Morshed
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Md. Habibur Rahman
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Department of Computer Science and Engineering
East West University, Mohakhali
Dhaka-1212, Bangladesh

Department of Computer Science and Engineering
East West University, Mohakhali
Dhaka-1212, Bangladesh

[email protected]

[email protected]

Md. Rezaur Rahman Mazumder

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K. A. M. Lutfullah
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Department of Computer Science and Engineering
East West University, Mohakhali
Dhaka-1212, Bangladesh

Assistant System Manager
East West University, Mohakhali
Dhaka-1212, Bangladesh

[email protected]

[email protected]

ABSTRACT

Mobile A d-hoc N etwork i s a d ecentralized network. There are

many r outing pr otocols ha ve be en pr oposed f or M obile A d-hoc
Network. In this paper, w e ha ve s imulated A ODV r outing
protocol to visualize the performance of AODV Routing Protocol.
AODV is a reactive p rotocol; it u ses tr aditional r outing ta bles.
This m eans t hat f or each d estination e xist one e ntry i n r outing
table and uses sequence number, this number ensure the freshness
of r outs a nd g uarantee t he l oop-free r outing. T o ev aluate t he
performance of A ODV r outing pr otocol, t he s imulation r esults
were an alyzed b y g raphical m anner an d t race f ile b ased o n QoS
metrics such a s D elay, J itter. T he s imulation r esult a nalysis
verifies the AODV routing protocol performance.

Keywords
AODV, MANET, QoS, Network Simulator (NS2).

1. INTRODUCTION

Mobile Ad-hoc Network (MANET) is a composition of a group of
mobile, wireless nodes which cooperate in forwarding packets in a
multi-hop fashion w ithout a ny c entralized a dministration. I n

MANET, each mobile node acts as a router as well as an end node
which is either source or destination. AODV is perhaps the most
well-known r outing pr otocol f or M ANET [ 1]. It offers qui ck
adaptation to dy namic l ink c onditions, l ow pr ocessing a nd
memory ov erhead, l ow ne twork ut ilization, a nd de termines
unicast r outes t o de stinations w ithin t he a d hoc network [2].
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Another usual characteristic is that it is an On-demand algorithm;
it determines a route to the destination only when packets send to
destination. If t he w ireless n odes ar e w ithin t he r ange o f each
other, the routing is not necessary. If a node moves out of range
then the node will not be a ble t o c ommunicate w ith ot hers
directly, i ntermediate n odes ar e n eeded t o o rganize the network
which takes care of the data transmission.


2. AODV PROTOCOL MECHANISM

Ad-hoc On-demand Distance Vector (AODV) routing protocol is
essentially a combination of both DSR and DSDV protocol [2]. It
borrows the basic on-demand mechanism of Route Discovery and
Route M aintenance f rom D SR protocol, plus t he us e of hop-byhop r outing, s equence num bers, a nd pe riodic be acons from
DSDV protocol [3]. The AODV protocol is loop-free and avoids
the count-to-infinity problem by t he us e of s equence num bers.
AODV protocol uses a s imple request-reply mechanism for route
discovery [4]. S ource node r equire a r oute t o sends a Routes
Request message to its neighbors. Source address and Request ID
fields uniquely identify th e R OUTE R EQUEST p acket to a llow
nodes to d iscard an y d uplicates t hey m ay r eceive. S equence
number of s ource a nd t he m ost r ecent v alue of destination
sequence number that the source has seen and the Hop count field
will keep track of how many hops the packet has traveled. When
source i nclude destination s equence numbers i n i ts r oute request
that a ctually l ast k nown de stination s equence number for a
particular destination. Every intermediate nodes store most recent

sequence number of source. I f a ne ighbor ha s a r oute t o
destination then it informs the source node. If neighbors have no
route then it rebroadcast R REQ a nd i ncrement hop c ount.
Eventually a route must be found i f e xists. I n r everse pa th
calculation, all nodes remember source o f t he R REQ. W hen a
route is found then it working backwards, route is discovered. The
receiver looks up the destination in its route table.

To t est f reshness i t c ompares de stination sequence number, if
RREQ p acket d estination sequence number i s g reater t han t he
Route destination sequence numbers assumes route is still present
and r emains unus ed. I f r oute i s f ound R oute R eply ( RREP)
message is returned to source.

3. SIMULATION TOPOLOGY

Simulation environment c onsists of 16 w ireless m obile node s
which a re pl ace uni formly a nd f orming a Mobile Ad-hoc
Network, moving about ov er a 1000 × 1000 m eters a rea f or 40
seconds of simulated time. We have used standard two-ray ground

propagation model, the IEEE 802.11 MAC, and omni-directional
antenna model of N S2. We ha ve us ed A ODV r outing a lgorithm
and interface queue length 50 at each node. The source nodes are
respectively 6, 15 and 5 and the receiving nodes are respectively
0, 1 and 11.

5. QoS METRICS

We used different parameter of QoS metrics such as delay, jitter,
packet drop, round trip time, a nd t hroughput t o unde rstand t he
behavior of AODV Routing Protocol.

6. SIMULATION RESULT
6.1 Drop

The routers might fail to de liver ( drop) s ome pa ckets i f t hey
arrive when their buffers are already full. Some, none, or all of the
packets might be dropped, depending on t he state of the network,
and it is impossible to determine w hat w ill ha ppen i n a dvance.
The r eceiving a pplication m ay a sk f or t his i nformation to be

retransmitted, p ossibly cau sing s evere d elays i n the overall
transmission. Table 2 s hows t he s cenario of t wo t ypes of pa cket
(TCP, U DP) f low f rom s ource t o de stination node w here U DP
packet d rop r ates o f U DP ar e g reater t han TCP packets. We use
Constant Bit Rate (CBR) as a User Datagram Protocol (UDP).
Table 2: Packet Drop of TCP and UDP
Packet type

Send

Receive

Drop

TCP

759

673


86

UDP

1963

1229

734

6.2 Throughput

Throughput i s t he m easurement of num ber of pa ckets pa ssing
through t he ne twork i n a un it o f tim e [ 5]. T his m etric s how th e
total n umber o f p ackets t hat h ave b een s uccessfully delivered to
Figure 1: Simulation Topology

the destination nodes and throughput improves with increasing
nodes density.


4. SIMULATION DESCRIPTION
Table 1: Simulation parameters
Value

Channel type

Channel/Wireless channel

Radio-propagation model

Propagation/Two ray round

Network interface type

Phy/wirelessphy

MAC type

Mac/802.11


Interface queue type

Queue/Drop Tail

Link Layer Type

LL

Antenna

Antenna/omni antenna

Maximum packet in ifq

50

Area (m×m)

1000×1000


Number of mobile nodes

16

Source type

UDP, TCP

Simulation Time

40 sec

Routing protocol

AODV

Sending Throughput (kbps)

Method

6.2.1 Transmission Throughput
700000

612864

600000
500000
400000
300000

202752

202240

202240

0─8

8─16

16─24

189440

200000
100000
0
24─32

32─40

Range of Time (second)

Figure 2: Transmission Throughput for UDP
Figure 2 s hows t he m aximum s ending t hroughput in th e tim e
interval of 24 t o 32 and sending throughput increased because of
node d ensity, l ess t raffic an d f ree o f channel. In rest of the time
the sending throughput was almost constant.

600000

503512
500000
400000
300000

236248
166144

200000

138320

98992
100000

Sending Throughput (kbps)

Sending Throughput (kbps)

600000

503512
500000
400000
300000
200000

236248
166144

100000
0

0
0─8

8─16

16─24

24─32

0─8

32─40

8─16

16─24

24─32

32─40

Range Of Time (second)

Range Of Time (second)

Figure 5: Receiving Throughput for TCP

Figure 3: Transmission Throughput for TCP
Figure 3 shows the time interval 24 t o 32 was maximum amount
TCP p ackets send from the s ource node be cause it shows t he
maximum job was done by the source node. In this particular unit
time interval sending throughput was high due to less traffic and
source and destination distance node close to each other.

6.2.2 Receiving Throughput

6.3 Delay

A s pecific p acket is tr ansmitting f rom s ource to d estination a nd
calculates the difference b etween s end t imes an d r eceived t imes.
Delays due to route discovery, queuing, propagation and transfer
time are included in the delay metric [6].
8

250000

7

190988

200000
150000

139916

6

131404
95760

100000

Delay

Receiving Throughput (kbps)

138320

98992

86184

5
4
3
2

50000

1
0

0
0─8

8─16

16─24

24─32

32─40

Range of Time (second)

Figure 4: Receiving Throughput for UDP
Figure 4 shows the m aximum r eceiving t hroughput in the tim e
interval of 16 t o 24 as w ell as m aximum am ount U DP p ackets
actually r eceived b y t he i ntended d estinations because in that
particular time interval the send node and receive node distance is
less, free of channel for those packets.
Figure 5 t he time r ange 8 t o 16 maximum T CP packets received
because i n t his p articular t ime r ange d estination n ode f ace l ess
traffic an d f ree ch annel w hich s hows t he m aximum w ork was
done by the intended destinations. A nd t he r est of t he t ime
interval r eceived t hroughput reasonably s table f or T CP p ackets.
From the Figure 2 t o F igure 5 s hows t hroughput w hich i s t he
number of r outing packets ( TCP, U DP) received successfully by
AODV routing protocol.

0

10

20

30

40

Send Time (second)

Figure 6: Send Time VS Delay Graph for UDP
Figure 6 shows t he d elay i s i ncreasing b ecause o f t he d istance
between sending and receiving nodes. From the Figure 6, the time
range b etween 0-20 s econds, t he de lay w as hi gh be cause i n t hat
particular ti me interval the di stance be tween s ending node a nd
receiving node is high due to traffic. And in the time interval 2040 sec the delay is less because of less traffic and free channel for
the UDP packets.

2

2

Jitter

Delay

1

1

0
0

10

20

30

40

-1
0
0

10

20

30

40

-2

Send Time (second)

Send Time (second)

Figure 7: Send Time VS Delay Graph for TCP

Figure 9: Send Time VS Jitter Graph for TCP

Figure 7 s hows af ter cer tain t ime i nterval t he d elay i ncreases
because of the node distance and busy nodes. The delay decreases
when the source and destination nodes close to each other while
having f ree ch annel an d minimum traffic. From Figure 6 a nd
Figure 7 w e conclude that there is trend of increasing delay with
increasing distance between source and destination, busy channel,
busy nodes and node density. When nodes keep on m oving more
frequently there will be m ore t opology c hanges a nd more lin k
breakages. This will cau se act ivation of routes discovery process
to find additional links. Thus packets have to wait in buffers until
new routes are discovered. This results in larger delay.

Figure 9 shows when the send t ime 10 j itter values was close t o
zero and after certain time interval jitter value increased and later
repeated old scenario for t he T CP p ackets. There i s a t rend o f
increasing o f j itter v alue w ith i ncreasing o f d elay between the
packets. Jitter values of routing packets (TCP, UDP) are affected
by p ackets d elay i f we co mpare F igure 7 with Figure 9 for TCP
data packets and Figure 6 with Figure 8 for UDP data packets.

6.4 Jitter

Jitter is the variation of the packet arrival time. In jitter calculation
the variation in the packet a rrival tim e is e xpected to m inimum.
The d elays b etween t he d ifferent p ackets n eed to be low if we
want better performance in Mobile Ad-hoc Networks.

6.5 Round Trip Time (RTT)

Round-trip tim e ( RTT), a lso called round-trip d elay, is th e tim e
required f or a s ignal p ulse o r p acket t o t ravel f rom a s pecific
source t o a s pecific d estination an d b ack ag ain. For each
connection, TCP maintains a variable, RTT that is the best current
estimation of round-trip time to the destination. When a segment
is sent, a timer is s tarted, b oth to s ee h ow lo ng th e
acknowledgement takes and to trigger a r etransmission if it takes
too long.

8

3

6
4
2
RTT

Jitter

2
0
-2

0

10

20

30

40

1

-4
-6
0
-8

0
Send Time (second)

Figure 8: Send Time vs. Jitter Graph for UDP
Figure 8 w e can s ee f ew s pikes are comparatively higher than
others because there were long delays, destination node far away
from source node, more t raffic a nd bus y c hannel. I n r est of t he
time UDP packets delay was low.

10

20

30

40

Send Time (second)

Figure 10: Send Time Vs RTT
In Figure 1 0 s hows th at in itially R TT d elay w as le ss. A fter a
certain t ime i nterval R TT i ncreased b ecause o f node distance,
node density, node mobility and more traffic. RTT delay increase
when i ntermediate node w as bus y node or congestion o ccurred

during the packet transmission. From Figure 10 Round Trip Time
(RTT) also affected by TCP delay which is shown in Figure 7.

7. CONCLUSION

In our simulation, we have s imulated a nd a nalyzed t he A ODV
routing pr otocol us ing di fferent pa rameter of Q oS metrics. A s a
reactive pr otocol AODV t ransmits network i nformation onl y ondemand. We have analyzed two types of data packets TCP, UDP
and both packet drop rate a re r espectively 11. 33% a nd 37. 39%.

For DSR and AODV Routing Protocol, packet delivery ratio is
independent of offered t raffic l oad, w ith bot h pr otocols
delivering between 85% and 100% of the packets in all cases
[4]. Comparing results we conclude that AODV routing protocol

perform w ell unde r v oice or d ata transmission but poor
performance for video transmissions as well as lack of Quality of
Service (QoS).
Simulation result shows the performance of T CP a nd U DP
packets with respect to delay, th roughput, jitte r, r ound tr ip tim e.
As a result, we can s ay t hat f or r eal t ime ap plications w e n eed
more r obust routing protocol which will pe rform be tter t han
AODV routing protocol.

8. REFERENCES

[1] Davide Cerri, Alessandro Ghioni, “Securing AODV: The ASAODV Secure Routing Prototype,” IEEE Communications
Magazine, February 2008.

[2] C. Perkins, E. Belding-Royer and S. Das, “Ad hoc OnDemand Distance Vector (AODV) Routing,” IETF RFC,
3561, July 2003.
[3] Geetha Jayakumar and G. Gopinath, “Performance
comparison of two on-demand routing protocols for Ad-hoc
networks based on random way point mobility model,”
American Journal of Applied Sciences, June 2008, pp. 659664.
[4] Geetha Jayakumar and Gopinath Ganapathy, “Performance
Comparison of Mobile Ad-hoc Network Routing Protocol,”
International Journal of Computer Science and Network
Security (IJCSNS 2007), vol. 7, no. 11, November 2007, pp.
77-84.
[5] Rekha Patil, DrA.Damodaram, “Cost Based Power Aware
Cross Layer Routing Protocol,” International Journal of
Computer Science and Network Security (IJCSNS 2008),
vol. 8 no. 12, December 2008, pp. 388-393.
[6] S H Manjula, C N Abhilash, Shaila K, K R Venugopal, L M
Patnaik, “Performance of AODV Routing Protocol using
Group and Entity Mobility Models in Wireless Sensor
Networks,” Proceedings of the International
MultiConference of Engineers and Computer Scientists
(IMECS 2008), vol. 2, 19-21 March 2008, Hong Kong, pp.
1212-1217.