Review of Routing Protocols in Ad Hoc Networks

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1 International Journal of Computer Engineering and applications,volumex,issuevi,june2016 Review of Routing Protocols in Ad Hoc Networks Harmandeep Kaur 1, Jabarweer Singh 2 1,2 Department of Computer Science & Engineering 1,2 GZS Campus College of Engineering & Tech. Bathinda, Punjab, India ABSTRACT: A mobile ad hoc network is a compilation of mobile nodes that are dynamically located in such a manner that the interconnections among nodes are capable of changing on a continual basis. In order to facilitate communication within network, a routing protocol is used to find out the routes between the nodes. The primary goal of ad hoc routing protocol is a proficient and correct route establishment between the pair of nodes. Therefore message may be delivered in timely manner. Route construction should be done with minimum bandwidth construction and overhead. This paper examines various routing protocols by presenting their characteristics, functionalities, benefits and disadvantages. The performance of AODV, DSDV and DSR is evaluated on the basis of three different parameters i.e. throughput, Energy consumption and packet delivery ratio using NS2. Simulation results shows that AODV provides better throughput, packet delivery ratio and less energy consumption. Keywords: Energy Consumption, AODV, Routing Protocols, Packet Delivery Ratio. [1] INTRODUCTION This Wireless network is divided into two classes such as infrastructure network and infrastructure-less network. An infrastructure-less network is known as an ad hoc network. An ad hoc wireless network is an accumulation of portable devices like mobile phones, laptops. The devices in ad hoc networks, can communicate with node inside their radio range or outside their radio range. An intermediate node works as router to deliver the packets in latter case. Ad hoc networks require some necessary properties. The nodes should be capable to sense the presence of other devices and should be able to execute the basic handshaking mechanism which is essential for communication.the nodes in ad hoc networks can be of various types. The capabilities and characteristics of these nodes can vary up to a large extent. Ad hoc networks are mobile, infrastructure less, and have low battery capacity[7].it provides an emerging technology for civilian and military applications. But it faces various challenges such as Design issues in robust medium access scheme: MAC is used to share a communication medium in network.mac plays an important role to decide the performance of a network. The main objective of a MAC protocol is fair distribution as well as efficient use of bandwidth. The MAC protocols should be able to minimize delay and maximize throughput. It should be able to support real time traffic. Harmandeep Kaur and Jabarweer Singh 48

2 Energy management: It can be performed via shaping of energy discharge pattern using routes with total minimal energy consumption using special task scheduling scheme with proper handling of the processor in addition to interface devices. Routing: In ad hoc networks, routes are multi hop because radio propagation range is limited and topology changes frequently and unpredictably as each network host moves randomly. Hence routing is an integral part of ad hoc communications. Routing is to discover and maintain routes between nodes in dynamic topology with possibly unidirectional links, using minimum resources. There are several issues such as mobility, band -width constraints, resource constraints, location-dependent contention which are faced by the routing protocol in ad-hoc networks.several routing algorithms are proposed, thereby trying to solve the routing problem in ad hoc networks. The next section discusses these protocols. TAXONOMY OF ROUTING PROTOCOLS IN AD- HOC NETWORKS Several routing protocols have been implemented for MANETs in order to improve bandwidth utilization, higher throughput, lesser overheads per packet, minimum consumption of energy. Ad hoc routing protocols possess two properties like qualitative properties(loop freedom,security) and quantitative properties(throughput, delay).most of them are quantitatively enabled. There are many ways to classify routing protocols in ad hoc networks depending on how the protocols handle the packets to deliver it from source to destination. However routing protocols are divided into three classes which are proactive, reactive and hybrid[2]. Proactive or Table-driven protocols: It always maintains current information of routes from one node to all other node in the network. Routing information is stored in the routing table of node and route updates are propagated in the network to store the recent routing information. But These protocols have some disadvantages such as irrespective amount of data for maintenance,slow reaction on restructuring and failures. The main examples of proactive protocols are destination sequence distance vector (DSDV), optimized link state routing (OLSR), wireless routing protocol (WRP). Reactive or on-demand protocol: These are also known as source initiated. Here routes create only when source requests a route to a destination. The route discovery process is used to create the route. Once a route is formed or multiple routes are formed to destination, the route discovery process comes to an end. The main disadvantages of these protocols are high latency time in route finding, excessive flooding.ad hoc ondemand distance vector (AODV), Dynamic source routing (DSR) are on-demand protocols. Hybrid protocols: This type of protocol combines the advantages of proactive and reactive routing. The routing is initially established with proactively prospected routes and then serves the demand from additionally activated nodes. The main disadvantage of such protocol is that these protocols depends on number of other activated nodes.zone routing protocol (ZRP) is a hybrid protocol. 49

3 International Journal of Computer Engineering and applications,volumex,issuevi,june2016 Figure1.Classification of routing protocols Distance Sequence distance vector (DSDV): It is one of the earliest ad hoc routing protocols. It depends on the Bellman -Ford algorithm. Every node maintains a routing table which contains the possible destinations in the network with hop counts and sequence number created by destination. This sequence number is used for identification of stale entries and for loop free routes[10]. Routing updates are forwarded through full dump and incremental. A full dump sends entire routing table to the neighbors and requires several network protocol data units. Incremental updates transmit only those entries which have changed since last full dump update. Only incremental updates are sent in stable network. The route labeled with most recent sequence number is used. Optimized link state routing (OLSR): It is the optimization of pure link state protocol. To reduce the overhead in network,multipoint relays (MPR) are used. MPRs guarantee the shortest to a destination by declaring as well as rearranging the link information periodically for their MPR s selectors[14]. By doing so, the nodes are able to gain topology information of the network. If there is any new significant change for the routing information, the updates are sent immediately. It reduces the number of nodes which broadcast the routing information in the network. Each node selects a set of one-hop neighbors which are called MPR for the node. The neighbors of the node which are not MPRs process the packets but don t forward them since only MPR forward the packets.mpr set must be chosen such that its range covers all two-hop neighbors. This set must be minimum set to broadcast the least number of packets. The multipoint relay set of node N should be such that every two-hop neighbors of N has a bi-directional link with node in MPR set of N. These links can be determined by HELLO packets containing information about all neighbors and link status. The source does not know complete routes, but only next hop information to forward the messages. Wireless routing protocol (WRP):It is based on Bellman Ford algorithm. The routing table in WRP contains an entry for each destination with next hop and cost metric. The route is chosen by selecting a neighbor node which minimizes the cost. To maintain the routing tables, update routing packets must be forwarded to all neighbors of node and contain all routes in which node is aware of. Only recent changes are included instead of whole routing table[13].to keep the links updated, empty HELLO packets are forwarded at periodic interval, only if no other update messages need forwarding. In figure2, there is a short example which is showing how WRP updates routing tables of nodes, when a link failure occurs. Link costs are as marked in this figure. The arrows which is next to links indicate the direction of update messages and the label in parentheses gives the distances as well as the predecessor to destination J. The figure focuses on update messages to destination J only. Figure 2.WRP routing protocol s operation [13] Harmandeep Kaur and Jabarweer Singh 50

4 Dynamic source routing (DSR): It is reactive protocol which is source initiated rather than hop-by-hop. This is considered for use in multihop wireless ad hoc networks. It allows the nodes to determine a route having multiple hops to any destination[10]. Each packet in its header carries an entire ordered list of nodes through which the packets must pass. Ad hoc on demand distance vector routing (AODV): It reduces the number of broadcast messages in network by discovering routes on-demand in reverse keeping a complete up-to-date route information. A source node which wants to send data to destination checks its route table to see if it has a valid route to destination node. If route exists, it forward the data.otherwise route discovery process starts, it broadcasts RREQ messages to all other nodes. This route request message contain sender IP Address, destination IP address, last known Sequence number. An intermediate node reply to RREQ Packet if its destination sequence number is greater than or equal to that sequence number which is in RREQ s header. When these nodes send packet further, these store the address of its neighbor from which it receive the packet. This information is used for route reverse for route reply packets. If same RREQ packet arrived later, that will be discarded[9].when route reply packet arrives from destination or intermediate node, the node forwards it along the established reverse and stores the forward route entry in their route table by using symmetric links. RERR packets are send when there is any failure in link, these packets are send to all its neighbor nodes. Figure3. Route discovery in AODV[1] Temporally ordered routing algorithm (TORA): It is based on the concept of route reversal. It finds multiple routes from source to destination. Three basic functions of this protocol are route creation, route maintenance, route erasure. Nodes use the metric height to set a direct acyclic graph rooted to destination during route creation and maintenance. The link may be upstream or downstream, it depends on the height metric of adjacent nodes. TORA s metric contain unique ID, Link failure s logical time, unique ID of node which defined new reference level, a reflection indicator bit.dag creation depends on query-reply process in LMR(Light weight mobile routing).the main strength of TORA is to handle failure of link. The reaction of TORA is optimistic to link failure. It reverse the link to re position DAG for searching an alternative. Each link reversal sequence searches for alternative routes to the destination. This mechanism requires a single pass of distributed algorithm since routing tables are modified simultaneously during outward phase of search procedure[12].the height metric is dependent on the logical time of a link failure. 51

5 International Journal of Computer Engineering and applications,volumex,issuevi,june2016 Parameter AODV DSDV DSR TORA WRP ABR OLSR Routing Structure Multiple route support Flat Flat Flat Flat Flat Flat Flat No No Yes Yes No No No Loop Free Yes Yes Yes Yes Yes Yes Yes Route Metric Utilize hello messages Overall complexity Frequency of update transmission Routing Scheme Periodic Updates Fresh and shortest Shortest Shortest Shortest Shortest Associatively and shortest Yes Yes No No Yes Yes Yes Shortest Medium High Medium High Low High Low Event On- Demand Periodically and as needed Table- Event On- Demand Event Hybrid No Yes No Yes, needed inside the zone Latency High Low High Inside Zone low, outside zone high Time complexity Bandwidth Requirement Updates transmitted to Periodically and as needed Table- Periodically On-Demand Periodically Table- Yes No Yes Low High Low O(2d) O(d) O(2d) O(2d) O(d) O(2d) O(d) Low High Low Medium High Low High Source Neighbors Source Neighbors Neighbors Source Neighbors Table1: Comparison of routing protocols Harmandeep Kaur and Jabarweer Singh 52

6 Zone routing protocol(zrp):the nodes have routing zone in ZRP. which defines a range that each node is required to maintain network connectivity proactively. Routes are immediately enabled to those nodes which are within routing zone. The routes are determined on-demand if node lie outside routing zone and it can use any on-demand routing protocol to determine the route to required destination[8].it reduces the communication overheads when compared to pure proactive protocols. It has reduced the delays linked with pure reactive protocols. [2] RELATED WORK In [1], authors give the comparison of AODV and DSDV protocols of ad hoc networks. NS simulator is used for performance comparison. In this paper topology of size 500*400m, simulation time is 150us with 4 wireless nodes among which 3 nodes move randomly and one is stationary. Throughput of AODV is better than that of DSDV over same interval of time and end -to-end delay of DSDV is less so it is more reliable than AODV and PDR of AODV is more than DSDV. In[3],authors evaluate the performance of DSDV,AODV,DSR based on throughput, PDR,ave-rage end-toend delay with network area 500*500m,number of nodes in 50,75,10 respectively by using simulatorns2(version 2.29).They analyze that the throughput of DSR is better than others. PDR of AODV and DSR is greater than DSDV protocol.dsr has shortest end-to-end delay than AODV and DSR.AODV need more time in route discovery. DSDV has high reliability than AODV and DSR. Overall DSR outperforms AODV because it has less number of routing overhead when nodes have high mobility. In [4],authors analyze the performance of four MANETs routing protocols such as DSDV,AODV,TORA using simulator NS-2.In which area of network is 1500*1500m,simulation time is 90 sec. Packet delivery ratio of AODV is greater than DSDV,DSR,TORA and in average end-to-end delay the reliability of DSR is greater than AODV,DSDV,TORA. In [5], paper traffic and mobility model based on continuous bit rate (CBR) traffic sources. Packet size is 512 bytes, area is 500*500 m with 10,20,50,100 nodes, simulation time is 100 sec. AODV has better performance when mobility increases. DSR could not achieve good PDR when moving more frequently and end-to-end delay for DSR is less than AODV. communication between 50 nodes in the network that are distributed in an area of 1300*1300m.The specifications of Simulation environment and process involved are shown in table below [3]SIMULATION RESULTS We have used NS2 simulator to show the simulation results of AODV, DSR, DSDV protocols. The two ray ground 53

7 International Journal of Computer Engineering and applications,volumex,issuevi,june2016 Parameter Simulator Number nodes Channel type Antenna type Transmission range Traffic model Simulation time of Value NS2(2.35) 50 Wireless Phy Omni antenna 250m CBR 5ms model is used for Harmandeep Kaur and Jabarweer Singh 54

8 REVIEW OF ROUTING PROTOCOLS IN AD HOC NETWORKS Figure 4.Throughput Figure 6 shows the energy consumption of AODV, DSDV, DSR in the network. The initial energy of network is 100 joules. At the end of network, remaining energy of AODV and DSDV is 94 joules. In the network, DSR consumed more energy as compared to AODV and DSDV. Figure 5.Energy consumption Figure 7 depicts packet delivery ratio of AODV,DSDV,DSR.The packet delivery ratio of AODV is more as compare to Packet delivery ratio of DSR and DSDV.DSDV has the lowest packet delivery ratio. 55

9 International Journal of Computer Engineering and Applications, Volume IV, Issue I & II, June16 Figure 6. Packet delivery ratio [4] CONCLUSION References The performance of AODV, DSR and DSDV is evaluated on the basis of throughput, energy consumption and packet delivery ratio. The simulation results show that AODV consumes less energy (decreases by 6%) as compared to DSR (decreases by 6.41%) and DSDV (decreases by 6.05%). AODV has more PDR in comparison to DSR and DSDV (lowest among all). The throughput of AODV is better than other two protocols. By comparing these protocols on the basis of various performance metrics, we have reached to a conclusion that AODV is better than other two protocols. [1] Rushikesh Dhananjay Imade, Rushikesh prataprao Bhoite, Akshay Sadashiv Bhoite, Performance comparison of AODV and DSDV routing protocols in MANET,dd International journal of technical research and applications,may-june [2] Ipsita Panda, A Survey on routing protocols of MANETs by using QoS metrics,"international journal of advanced research in computer science and software engineering,oct [3] Manickam,T.guru baskar, M.Girija, Dr. D.Manimegalai, performance comparisions of routing protocols in MANET, IJWMN, February [4] Meenakshi Sharma, Pooja Saini, Performance analysis of routing protocols over multimedia streaming in MANET,IJSR,June [5] Mohammand Bouhorma, H.Bentaouit and A.Boudhir, Performance comparisons of Ad hoc routing protocols AODV and DSR, IEEE [6] D.Johnson, The dynamic source routing, RFC 4728,Feb [7] Manoj B.S, Ad hoc wireless network: Architectures and protocols, Prentice hall of india,2004. [8] Mehran Abolhasan,Tadeusz Wysoci,Eryk Dutkiewicz, A Review of routing protocols in MANETs, ELSEVIER,2003. [9] C.Perkins, Ad hoc on demand distance vector routing, RFC 3561 July2003. [10] Mehran Abolhasan, Tadeusz Wysocki and Eryk Dutkiewicz, A review of routing protocols for mobile ad hoc networks, Elsevier [11] E. M. Royer and Chai-Keong Toh, "A review of current routing protocols for ad hoc mobile wireless networks," in IEEE Personal Communications, vol. 6, no. 2, pp , Apr [12] Vincent D. Park and M. Scott Corson, A performance comparison of TORA and Ideal Link State routing, In Proceedings of IEEE Symposium on Computers and communication, June [13] Petteri Kuosmanen, Classification of Ad Hoc Routing Protocols,IJSRD,may Harmandeep Kaur and Jabarweer Singh 56

10 REVIEW OF ROUTING PROTOCOLS IN AD HOC NETWORKS [14] [15] M.Gerla,C.Chiang and L.Zhang, Tree multicast strategies in mobile,multihop wireless networks, ACM/Blitzer mobiles networks and Apps.J.,1998. Author[s] brief Introduction Corresponding Address- (Pin code and Mobile is mandatory) 57