Behaviour and Analysis of MANET Routing Protocols for an Emergency and Rescue Scenario

Behaviour and Analysis of MANET Routing Protocols for an Emergency and Rescue Scenario

Mahalakshmi S

Assistant Professor; BMSIT Bangalore, India

Apoorva V Student; BMSIT Bangalore, India

Huzefa Mehnaz Student; BMSIT Bangalore, India

Rakshitha M R Student; BMSIT Bangalore, India

Abstract A collection of wireless mobile nodes, without a fixed infrastructure or central administration is termed as a Mobile Ad-Hoc Network (MANET). These characteristics of MANET make it suitable for an emergency and rescue scenario which requires effective communication. Routing strategies: proactive, reactive and hierarchical are considered, under which DSDV, DSR, AODV and CBRP are simulated and analysed for better performance in an emergency and rescue topography. NS2 simulator has been used for the study. From the comparative analysis of routing protocols it can be shown that the hierarchical routing strategy has a better performance in terms of parameters such as throughput, end to end delay, packet drop and packet delivery ratio for an emergency and rescue scenario.

Keywords AODV, DSDV, DSR, CBRP, MANET, ERS

1. INTRODUCTION

   A Mobile Ad Hoc Network (MANET) is a collection of wireless nodes that can dynamically configure a network to exchange the information without using any fixed network infrastructure[5]. MANETs do not need any pre-existing network infrastructure or base stations to create a network[4]. As the network does not consist of routers, each mobile device will not only act as source and destination, they also act as router routing the information from one node to another and because the structure of the network can change quickly and unpredictably the network will be able to adapt to the changes very quickly making it ideal for emergency and rescue scenarios where communication is expected to occur with minimum loss and in an energy efficient manner.

   This paper aims to determine which one of the MANET routing strategies: proactive, reactive or hierarchical, performs better in an emergency and rescue operations with respect to random waypoint mobility model to provide uninterrupted service to the mobile users irrespective of the geographical location and the speed at which the mobile user is moving and to provide information to service providers helping them decide and implement a well suited and robust communication protocol during emergency and rescue scenarios.

2. RELATED WORK

   Routing is considered to be a parameter for effective communication in an ERS. This paper makes a comparative analysis of routing protocols under three categories: proactive, reactive and hierarchical in an ERS.

   1. MANET routing protocols

      Proactive/table driven routing: All the mobile devices which are a part of the network will exchange routing information or routing table periodically. The route is maintained at all the nodes and it reacts to the addition of a new node into the network. The main idea is to distribute the information periodically though the networks in order to pre calculate all the possible paths and changes are propagated to all the nodes. Too much of updating may cause over loading which directly affects the utilization of bandwidth and energy efficiency. But the proactive protocols are better in terms of performance and packet delivery fraction and are most suitable in static topology. Eg: DSDV, CGSR, WRP etc

      Reactive/source initiated routing: The paths for the devices will be decided when the source makes a request for transmission that is, routing table exchange does not take place. It allows the update of the tables on demand. This can be done in two parts: Route discovery which occurs when node wants to communicate with the specific destination and Route maintenance which is used to maintain the path failure caused by mobility of nodes. The drawback of these protocols is the latency to initiate communication. Reactive protocol would be energy saving during communication, since a non- constant network update improves energy saving on mobile devices. Eg: DSR, TORA, ABR, AODV etc.

      Hierarchical routing: The protocol divide the MANET into groups of nodes called clusters, where in a cluster head is responsible for distribution of information across the network generated in its cluster. Such a routing protocol is essential for an emergency and rescue scenario as there is a central administrator for each cluster, thus providing faster communication, saves energy and bandwidth, and has better network performance. Proactive protocol DSDV, reactive protocols AODV and DSR and hierarchical protocol CBRP was chosen under the following considerations:

      AODV and DSDV were chosen because they showed the best performance in their categories[3]. CBRB is a protocol which uses DSR as a back end; hence there is a need to evaluate the performance of DSR with CBRP. CBRP a reactive protocol shows significant advantage in energy consumption, bandwidth and network performance[2]. To evaluate the performance of the above mentioned protocols for an ERS, the parameters throughput, end-to-end delay, packet drop and packet delivery ratio are considered.

   2. Methodology for performance analysis of routing protocols

      The analysis is carried out in three phases: preparation, study and analysis, results and conclusion. Preparation involves creation of scenario with mobile nodes followed by study and analysis of protocols with respect to number of nodes and parameters. The final phase includes results generation as shown in figure1.

      Fig 1: Method for result generation

   3. Proposed Scenario

      Simulation is carried out considering the scenarios with 25, 50, 75 and 100 nodes.

      To define the simulation scenarios the basic values and parameters for different protocols are as shown in Table1.

   4. Performace Metrics

      In order to determine a better protocol for an ERS, the following parameters were considered:

      • Throughput: It is a significant measure for an ERS, it describes the rate of successful delivery of message over a communication channel, measured in bits per second. Fig 1 demonstrates high throughput value of CBRP protocol compared to DSDV,AODV and DSR even with the increase of the number of nodes.

      • Packet drop: It is the number of packets dropped by intermediate nodes due to mobility, link breakage, expiration of time etc. Fig 2 shows the erratic behaviour of packet drop in CBRP for 75 nodes due to different speeds of nodes and mobility, but is the least packet drop compared to the other protocols for the other sets of nodes.

      • Packet Delivery Ratio: It is the ratio defining the number of packets sent verses the number of packets received. Higher packet delivery ratio indicates better the performance. Fig 3 shows a significant high packet delivery ratio in CBRP across the increasing number of nodes.

      • End-to-end delay: It is the time taken by the packet to arrive at the destination which includes route discovery time, queueing time, propagation time. Lower end-to-end delay indicates better performance. Fig 4 shows CBRP demonstrating a moderate end-to- end delay across the increasing number of nodes when compared to the variations in the other protocols.

   Table 1. Basic Values and Parameters

   Variable	Value	Observations
   set val(chan)	Channel/WirelessChannel	channel type
   set val(prop)	Propagation/TwoRayGround	radio-propagaton model
   set val(netif)	Phy/WirelessPhy	network interface type
   set val(mac)	Mac/802_11	MAC type
   set val(ifq)	Queue/DropTail/PriQueue	interface queue type
   set val(ll)	LL	link layer type
   set val(ant)	Antenna/OmniAntenna	antenna model
   set val(ifqlen)	25	max packet in ifq
   set val(nn)	25,50,75,100	number of mobilenodes
   set val(rp)	DSDV, AODV,DSR, CBRP	routing protocol
   set val(x)	1000	X dimension of topography
   set val(y)	750	Y dimension of topography
   Set val(stop)	100	Simulation time

   Table 2. Throughput

   No. of nodes	AODV	CBRP	DSDV	DSR
   25	220.221	232.229	215.37	220.485
   50	218.009	223.309	214.577	213.671
   75	180.157	237.134	213.834	216.411
   100	213.728	221.701	22.4975	214.132

   No. of nodes	AODV	CBRP	DSDV	DSR
   25	14	5	31	7
   50	22	11	13	37
   75	3	29	36	6
   100	17	17	5	20

   Fig 2. Throughput Table 3. Packet Drop

   Fig 3. Packet Drop

   Table 4. Packet delivery ratio

   No. of nodes	AODV	CBRP	DSDV	DSR
   25	99.2887	92.2327	85.1192	97.8368
   50	99.2068	99.1024	71.887	94.8254
   75	99.4537	87.676	61.1444	94.8206
   100	99.4207	98.0342	11.2708	94.215517

   No. of nodes	AODV	CBRP	DSDV	DSR
   25	175.184	229.133	115.218	258.485
   50	170.76	265.542	59.3577	170.354
   75	176.144	221.211	12.0779	25.803
   100	184.446	272.08	0	270.83

   Fig 4. Packet Delivery Ratio Table 5. End-to-End Delay

   Fig 5. End-to-End Delay

3. CONCLUSION

This study for the evaluation and comparison of DSDV, AODV, DSR and CBRP shows that the best protocol for an ERS is CBRP. Though a little loss of information takes place during routing, and there is fluctuation in the data rates, CBRP performs better in comparison to the other protocols. Hence it can be shown that a hierarchical protocol, CBRP is well suited for an ERS, allowing a better evacuation of persons to an appropriate location.

REFERENCES

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