Routing Protocol In Mobile Ad Hoc Networks

Published Date: 02 Nov 2017

A mobile ad hoc network or MANET is built up of a collection of two or more autonomous nodes which communicate with each other openly without any centralized administering node. MANET possesses few salient features such as dynamic topology, limited storage and bandwidth, thus it is quite hard to route packets efficiently and accurately to a particular destination node as compared to traditional wired networks. This type of networks lack in fixed topology hence they are often known as infrastructureless networks where each node has the capacity to work both as router or host or both. Routing in MANET is still a challenging task and has gained a remarkable attention from researchers worldwide. This has led to the development of different routing protocols with each protocol providing an improved version in respect to various strategies for a particular network scenario. From the past two decades, network communities have designed a number of routing protocols for wireless networks which operate under varying scenarios and mobility. It has been observed from the literature survey that none of the existing protocols is the best that justifies the characteristics and is suitable to perform an efficient and superior routing. We strive to uncover the efficiency of existing routing protocol by enhancing its performance in terms of throughput, end to end delay and packet delivery.

Lot of techniques exist which can be applied on the existing protocols to make them more efficient and better. In this study we have implemented a branch of Swarm Intelligence (SI) i.e. Ant Colony Optimization (ACO) or simply called ant based routing, to enhance the performance of existing Dynamic Manet On demand (DYMO) routing protocol. Ant based routing resembles basic mechanisms from SI in real biological environments and has turned out to be an efficient technique to boost up the performance of routing protocols. It is becoming more popular day by day because of its dynamic and adaptive nature. It is inspired by real life ants which are able to search the shortest path to reach their food source. They do so by depositing a considerable amount of special substance called pheromone. In ant routing, the ants or control packets are responsible to store the information which is used to build and update the routing tables generated at each node. A number of ant based routing mechanisms have been proposed by researchers that have presented and compared in the study. We have proposed an enhancement of existing DYMO routing protocol by implementing ant agents and observed favourable results. Also multiple routes have been computed using ant packets and pheromone values during route discovery which would rather help in selecting alternate paths in case of any link break or node failure.

DYMO is a purely reactive on demand protocol based on the concept of source routing. It is also known as the successor of AODV or simply AODVv2. It is based on the mechanism of AODV with additional source routing feature i.e. it is a combination of both AODV and DSR. It computes new routes based on source routing technique of DSR. TCP agents are used to route the packets from source to destination. Every node maintains all the information related to routing in its routing table which helps in discovering new paths and maintaining the existing paths. An effort has been done to implement DYMO in an ad hoc network with arbitrary topology and implemented ant agents instead of TCP agents for all the nodes under different scenarios with varying nodes and pause time.

The proposed protocol is named as E-DYMO i.e. enhanced DYMO. It is an ant based hybrid on demand routing protocol for mobile ad hoc networks which is proactive as well as reactive in nature. The proactive part implements the original DYMO technique to discover new routes from source node whereas the reactive part implements ACO technique. Routing tables have been generated for every source node to a valid destination along with the pheromone values. A set of multiple paths has been computed for each destination node from all the sources by finding the pheromone values. From paths available, the best shortest path could be selected based on the cumulative pheromone values calculated for each path. As the pheromone value is inversely proportional to the length of path, we would select the path with maximum pheromone value. The higher is the pheromone value the shorter is the path. It has been observed that the proposed protocol works better than the original protocol in terms of packet delivery, end to end delay and throughput but incurs a slightly high routing overhead which is due to the extra ant packets generated at the source nodes.

Objectives

The primary objective of this research is to enhance the performance of an existing routing protocol in a mobile ad hoc network. Towards this proposed research, the following contributions have been expected:

To provide an overview of existing routing protocols and mechanisms in mobile ad hoc networks.

To effectively analyze and compare the performance of existing routing protocols with respect to different parameters, and to propose modifications (if any) of the existing routing protocols in mobile ad hoc networks.

To propose an efficient routing protocol and to evaluate the same.

Work done

The thesis work first describes a comprehensive comparison of different routing protocol categories. All these protocols have been simulated in varying network scenarios. Then an arbitrary ad hoc network has been designed and ant agents have been applied on existing DYMO protocol. The proposed routing protocol has been simulated on network simulator ns2.34. Finally results have been compiled and compared with the existing version of the protocol in terms of different performance metrics such as throughput, end to end delay, packet delivery fraction and routing overhead. The compiled results verify that the proposed version of protocol is an enhancement to the existing protocol and is more efficient.

The schematics of the study are as follows:

Including the first introductory chapter, this thesis contains a total of 6 chapters; Literature review, Implementation of DYMO routing protocol, Implementation of the proposed routing protocol, Results and discussions, Conclusions and future scope.

Chapter 2 presents a comprehensive literature review and provides an overview of existing routing protocols and mechanisms followed by a critical comparison. It also focuses on various algorithms that are based on swarm intelligence and ant colony optimization. A detailed comparison has been presented between all the important algorithms. Further a detailed survey has been done on various existing mobility models on which the whole network scenario is designed. Part of this work has been accepted and published in [5, 7, 9, and 11 (see page 9, 10)].

Chapter 3 shows the implementation of DYMO routing protocol and analyses its performance with other similar protocols against different parameters. Part of this work has been published in [4 and 12 (see page 9, 10)].

Chapter 4 discusses implementation of proposed routing protocol and the technique applied to enhance the performance of implemented DYMO. Ant colony optimization technique has been applied to enhance its performance. It has been studied that applying this technique enhances the performance of a routing protocol which has been shown with the help of simulations done using ns2 in next chapter. Part of this work has been published in [10, 13 and 14 (see page 9, 10)].

Chapter 5 of the thesis highlights the simulation of proposed efficient routing protocol which is effectively done with respect to varying network size and pause time. The proposed routing protocol has been analyzed by making use of a simulated environment and compared with the original version. It has been observed that by applying ACO technique to existing routing protocol enhances its performance in terms of varying network parameters. Also multiple paths have been generated at the source node to destination which are helpful in case of link break or node failure.

Summary

The existing DYMO routing protocol has first been installed and simulated with a pre-defined network scenario. Values for various performance metrics have been computed and compared with other existing protocols of same category. Then, the written TCL/Tk script has been modified to take into account the proposed enhancement. The modified script implements proposed E-DYMO routing protocol. As per the suggestions advised by Tracy camp a warm up time of 800 sec has been taken into account for all the simulations performed before the initialization of actual simulation. For all the simulations performed, five different network scenarios have been considered. Scenario 1 is for very small network size of 20 nodes. Scenario 2 is for small network size of 30 nodes. Scenario 3 is for medium network size of 40 nodes. Scenario 4 is for large network size of 50 nodes. And scenario 5 is for very large size network of 60 nodes. Four metrics i.e. packet delivery ratio, end to end delay, routing overhead and throughput have been considered for all the simulations. A total of 6 simulation rounds have been performed for every metric and average value for each metric has been taken to compile the results.

Table 1 shows the average values computed for all the metrics with respect to varying number of nodes at a pause time of 100 sec.

Table 1. Average values for performance metrics

Nodes

(PDF)

(E2E)

(RO)

(TP)

DYMO

E-DYMO

DYMO

E-DYMO

DYMO

E-DYMO

DYMO

20

84.26

85.6

0.035

0.032

1267

1278

86.5

30

83.07

84

0.04

0.034

2003

2097

88.05

40

65.11

68.8

0.054

0.045

2451

2879

78.98

50

84.6

88.2

0.048

0.04

3663

3788

89.14

60

72.2

76.5

0.081

0.06

5935

6106

86.69

Figure 1 to 4 show the overall comparison of implemented DYMO versus proposed E-DYMO routing protocol. Charts have been plotted considering varying pause time and network size i.e. nodes. The following charts have been computed at 100 pause time versus varying number of nodes for different performance metrics i.e. packet delivery fraction, end to end delay, routing overhead and throughput respectively.

Figure 1. Packet delivery fraction

Figure 2. End to end delay

Figure 3. Routing overhead

Figure 4. Throughput

A concise comparison chart has been presented in table 2 below for different protocols considered with respect to performance metrics taken.

Table 2. Analysis of simulated Routing Protocols

Parameters

AODV

DSR

DYMO

E-DYMO

Throughput

Medium

High

Medium

High

PDR

Medium

High

Medium

High

End to end delay

Low

Medium

Low

Very low

Overhead

High

Low

Low

Medium

Finally, Chapter 6 summarizes the contribution of this thesis. It has been observed that the proposed protocol i.e. E-DYMO performs better in terms of all the metrics considered but incurs a little high overhead that the existing DYMO protocol which is within tolerable limits. This is because of the extra traffic generated by introducing special ant packets. These ants have been proven as beneficial in computing multiple paths based on the pheromone values of each route from source to destination node. At the last a number of directions on the presented work have been provided that would help researchers for future research.

List of publications by the author

Anuj K. Gupta, "Secure routing techniques in mobile ad hoc networks", APPL-1079, pp. – 813-817, Proceedings of 2009 IEEE International Advance Computing Conference, ISBN: 978-981-08-2465-5, Thapar University, Patiala, 6-7 Mar 2009.

Anuj K. Gupta, Harsh Sadawarti, "Secure Routing Techniques for MANETs", International Journal of Computer Theory and Engineering (IJCTE), ISSN: 1793-8201, Article No. 74, 1(4): 456-460, October 2009.

Anuj K. Gupta, Harsh Sadawarti, "Security aspects in ad hoc network routing", Article No.6 , pp. – 32-37, Proceedings of International Symposium on Computer Engineering & Technology (ISCET 2010), ISBN: 978-81-910304-0-2, RIMT, Mandi Gobindgarh, 19-20 March 2010.

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "Performance analysis of AODV, DSR and TORA Routing Protocols", International Journal of Engineering & Technology (IJET), ISSN: 1793-8236, Article No. 125, 2(2): 226-231, April 2010.

Anuj K. Gupta, Anil K. Verma, Harsh Sadawarti, "Analysis of various Swarm-based & Ant-based Algorithms", Proceedings of International Conference on Advances in Computing and Artificial Intelligence (ACAI 2011), an ACM Chapter Event, Chitkara University, Punjab, pp – 39-43. http://dl.acm.org/citation.cfm?id=2007052, 21-22 July 2011.

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "A Review of Routing Protocols for Mobile Ad Hoc Networks", WSEAS Transactions on Communications, ISSN: 1109-2742, 11(10): 331-340, November 2011 (SJR- 0.039, H index- 7).

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "Review of various Routing Protocols for MANETs", International Journal of Information & Electrical Engineering (IJIEE), ISSN: 1109-2742, Article No. 40, 1(3): 251-259, November 2011.

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "Effect of mobility parameters on the performance of AODV routing protocol", International Journal of Mobile & Network Technology (IJNMT), ISSN: 2229-9114, 3(1) :14-20, January 2012.

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "MANET routing protocols based on Ant Colony Optimization", International Journal of Modelling & Optimization (IJMO), ISSN: 2010-3697, 2(1): 42-49, February 2012.

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "Computation of Pheromone values in the AntNet Algorithm", International Journal of Computer Network and Information Security (IJCNIS), ISSN: 2074-9104, 4(9): 47-54, August 2012.

Anuj K. Gupta, Harsh Sadawarti, Anil K. Verma, "Review of Mobility Models in Mobile Ad hoc Networks",

Jatinder Kaur, Sandeep Kaur, Anuj K. Gupta, "Comparison of DYMO, AODV, DSR and DSDV MANET routing protocols over varying traffic", International Journal of Research in Engineering & Applied Science (IJREAS), ISSN: 2294-3905, 1(2): 71 – 83, October 2011.

Bhavna Talwar and Anuj K Gupta. "Ant Colony based Mobile Ad Hoc Networks Routing Protocols: A Review", International Journal of Computer Applications (IJCA), 49(21): 36-42, July 2012. 

Bhawna Talwar, Anuj K.Gupta, "Implementation of ACO on Wireless Mesh Ad Hoc Networks", Proceedings of International Conference on Technical and Executive Innovation in Computing and Communication (TEICC 2012), ISBN: 978-81-923777-0-4, Veterinary University, Bikaner, Rajasthan, pp. 588 – 592, 27-28 Dec 2012.

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