Simulation and Analysis of Ad hoc On dem

Simulation and Analysis of Ad-hoc On-demand Distance

Vector Routing Protocol

Md. Monzur Morshed

Tiger Hats

Department of Computer Science and Engineering East West University, Mohakhali

Dhaka-1212, Bangladesh

m.monzur@gmail.com

Md. Rezaur Rahman Mazumder

Tiger Hats

Department of Computer Science and Engineering East West University, Mohakhali

Dhaka-1212, Bangladesh

m_rezaur@yahoo.com

Md. Habibur Rahman

Tiger Hats

Department of Computer Science and Engineering East West University, Mohakhali

Dhaka-1212, Bangladesh

mmmhabib@gmail.com

K. A. M. Lutfullah

Tiger Hats

Assistant System Manager East West University, Mohakhali

Dhaka-1212, Bangladesh 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 graphical manner an d trace file 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].

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 Maintenance from DSR protocol, plus the use of hop-by-hop 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 include destination sequence numbers in its route 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 for 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 NS2. We have used AODV routing algorithm 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.

Figure 1: Simulation Topology

4.

SIMULATION DESCRIPTION

Table 1: Simulation parameters

Method 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

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 the 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 shows the scenario of two types of packet (TCP, U DP) f low f rom s ource t o de stination node w here U DP packet drop rates of UDP are greater than 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 total n umber o f p ackets that h ave b een successfully delivered to the destination nodes and throughput improves with increasing nodes density.

6.2.1

Transmission Throughput

202752 202240 202240

Figure 2: Transmission Throughput for UDP

166144

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

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 well as m aximum amount 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 range 8 to 16 maximum TCP 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 routing packets (TCP, UDP) received successfully by AODV routing protocol.

Figure 5: Receiving Throughput for TCP

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 send times an d received times. Delays due to route discovery, queuing, propagation and transfer time are included in the delay metric [6].

0

0

Figure 7: Send Time VS Delay 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 moving more frequently there will be m ore t opology c hanges a nd more lin k breakages. This will cause activation 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.

6.4

Jitter

Jitter is the variation of the packet arrival time. In jitter calculation the variation in the packet arrival time is expected to minimum. 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.

-8

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.

-2

Figure 9: Send Time VS Jitter Graph for TCP Figure 9 shows when the send time 10 j itter values was close to 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 packets delay if we compare Figure 7 with Figure 9 for TCP data packets and Figure 6 with Figure 8 for UDP data packets.

6.5

Round Trip Time (RTT)

Round-trip time ( RTT), also called round-trip d elay, is th e time 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.

Figure 10: Send Time Vs RTT

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 protocol using di fferent parameter of QoS metrics. A s a reactive protocol AODV transmits network information only on-demand. 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, throughput, jitter, round trip time. 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 A-SAODV Secure Routing Prototype,” IEEE Communications Magazine, February 2008.

[2] C. Perkins, E. Belding-Royer and S. Das, “Ad hoc On-Demand 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. 659-664.

[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