Council for Innovative Research

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1 ISSN PERFORMANCE EVALUATION OF MULTIPATH ROUTING PROTOCOL IN MOBILE AD-HOC NETWORK Sanjeev Kumar, Yogesh Chaba Computer Science Engineering Department, Guru Jambheshwar University Science &Technology, Hisar (HRY) Abstract A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without using any existing infrastructure. Due to the dynamic nature of the network topology congestion and load balancing are the major problem in Mobile Ad-hoc Networks routing. Most of the existing protocols provide solutions to load balancing or congestion or fault tolerance individually. In this paper a load balancing algorithms (Balanced Multipath Source Routing) is implemented and analyzed. BMSR protocol distributes the traffic load over multipath route according to its minimum weight. The BMSR is implemented in NS and evaluate the performance based on metrics like throughput packet delivery ratio delay. The performance are measured and compared with existing DSR protocol. In this paper, the simulation results show that the BMSR algorithm solves the problem of congestion through load balancing in different scenarios through which BMSR outperforms DSR significantly. Keywords: MANET, BMSR, DSR, Load Balancing. Council for Innovative Research Peer Review Research Publishing System Journal: INTERNATIONAL JOURNAL OF NETWORKING & PARALLEL COMPUTING Vol 3, No. editor@cirworld.com member.cirworld.com 78 P a g e N o v e m b e r 8, 3

2 ISSN I. INTRODUCTION MANET[5] is a network having dynamic topology that consists of mobile nodes without base Station or centralized control. MANET is a self-organized and self configuring multihop wireless network. Due to the less transmission range of mobile node, multihop pattern is followed for passing the information. Packets passed through intermediate nodes while moving from source to destination. All mobile nodes perform functioning of routers that search and maintain routes to other nodes in the network. Routing is the process of choosing which paths to be used to send network traffic, and sending the packets along the selected sub-network. In MANETs, mobile nodes communicate with each other in a multi-hop fashion. That means a mobile node sends a packet to a destination through intermediate nodes. Hence, the availability of each node is equally important. Routing protocols designing goals are optimality, simplicity, low overhead, robustness, reliability and flexibility. Routing protocols are classified two categories, proactive and reactive protocols. Proactive protocols are also known as table driven protocols. In table driven protocols like DSDV, nodes maintain one or more routing tables about nodes in network and there is regular exchange of network topology packets between nodes of network. The main drawback of proactive routing protocols is massive exchanges of information periodically that consume more bandwidth and power. On the other hand reactive protocols initiate a route only when a node wants to start communication with another node. Route request and Route reply messages are used to discover and store the paths found from the source to destination. After finding the paths, suitable shortest path is selected by the source node for the transmission. Route discovered by reactive algorithms having problems like congestion problems as the centre of network carry more traffic. This causes poor performance in reactive protocol. To remove all these shortcomings, multipath routing protocols have been proposed. In unipath routing protocols are discovered a single route between source and destination. The rest of the paper is organized as follows: Section.describe the multipath routing protocols Section 3. reviews the previously work done on related algorithms Section 4 explain its experiment set up and its matrices. Section 5 describes the performance evaluation of routing protocol. Conclusions are remarked in section 6. II. MULTIPATH ROUTING PROTOCOLS Multipath Routing [6]is the process of distributing the traffic load over multiple paths. Multipath algorithms permit traffic multiplexing over multiple lines. Multipath Routing provides better performance by proper utilization of network resources. Multipath routing protocols provides better throughput and reliability than unipath protocols. The objectives of multipath routing protocols [4] are to maintain reliable communication, to reduce routing overhead by use of secondary paths, to ensure load balancing, to improve quality of service, to avoid the additional route discovery overhead. Numerous multipath routing protocols have been proposed for wireless ad hoc networks. Many of them are based on the popular on-demand routing protocols, DSR and AODV.. Dynamic Source Routing (DSR) The Dynamic Source Routing protocol (DSR) [9] is a simple and efficient routing protocol designed specifically for use in multi-hop wireless ad hoc networks of mobile nodes. Each data packet carries the complete path from source to destination as a sequence of IP addresses. DSR protocol coupled both the source routing mechanism with on demand process. The DSR protocol consists of two mechanisms: Route Discovery and Route Maintenance. Route discovery is initiated by a source whenever a source has a data packet to send but does not have any routing information to the destination. To establish a route, the source floods the network with request messages carrying a unique request ID. When a request message reaches the destination or a node that has route information to the destination, the node sends a route reply message containing path information back to the source. In order to reduce overhead generated during a route discovery phase, the route cache maintained at each node records routes the node has learned and overheard over that time frame. Route Maintenance is the mechanism by which the source of a packet detects network topology changes that render useless its route to the destination. When Route Maintenance indicates a source route is broken, source is notified with a ROUTE ERROR packet. The sender can then attempt to use any other route to destination already in its cache or can invoke Route Discovery again to find a new route.. Balanced Multipath Source Routing (BMSR) BMSR, is implemented on top of DSR protocol. BMSR used for obtaining multiple source-destination routes for a given source-destination pair with minimum flow congestion []. The algorithm relies on the computation of shortest paths determined by an adaptive cost metric using weights on the links. Each source having a balanced collection of routes to the destination the effect of a single link failure diminishes, as the source distributes the traffic equally among the routes in the cache. Each shortest path computed becomes a source route for the BMSR protocol. The data flow is then equally distributed over these pre-computed routes. In BMSR route request packet, BREQ, that contains a record of the total weight of the path the BREQ has taken so far. If a node receives a BREQ packet related to a route request it has already seen, it may resend it if the second packet has a lower weight than the previously seen BREQ packets related to the same route request. This allows us to find routes of minimum weight. After receiving a BREQ packet the intended destination waits for a while, aiming to make sure that lower weight routes represented by BREQ packets that arrive later are taken into account in choosing the route. The destination 79 P a g e N o v e m b e r 8, 3

3 ISSN then sends a route reply packet back to the source, and all nodes on the path update the weights of the edges on the path. III. RELATED WORK Multipath routing is a natural choice for distributing the load evenly across the network. One important component of load balancing is that of traffic distribution. There are two strategies for distibuting traffic using multiple paths[3]. In one load balancing strategy,multipath routing protocol may decide to forward the traffic over only one lightly loaded path and keep others as backup paths[4],[5] and in other case, traffic may be distributed over multiple paths concurrently[6],[4]. Load balancing protocols adopt metrics that characterize existing load or traffic on the paths and try to avoid such congested areas. Hence, routing paths discovered by load balancing protocols are always longer than shortest hop metric based routing protocols. One of the earliest works, MSR[6] introduces load balancing which distributes traffic using weighted round robin scheduling strategy. The criterion used to distribute the load is based on round trip time or RTT which is not an effective method of load evaluation. [4] distributes load such that total number of congested packets on each path is equal and does load splitting at packet level granularity. David B. Johnson, et.al [9] describes Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol. The protocol is composed of the two mechanisms of Route Discovery and Route Maintenance, which work together to allow nodes to discover and maintain source routes to arbitrary destinations in the ad hoc network. Roy Leung, et.al [] proposed MP-DSR based on the existing DSR and takes advantage of its distributed on-demand nature. In MP-DSR First, define our QoS parameter of interest, end-to-end reliability. Second, propose a fully distributed QoS routing protocol, MP-DSR, with respect to this QoS parameter. Kui Wu, et.al [3] propose an on-demand method to efficiently search for multiple node disjoint paths and present the criteria for selecting the multiple paths. H. Zafar, et.al [7] provides benefit of fault tolerance, load balancing, bandwidth aggregation and the improvement in quality-of-service. Sung-Ju Lee, et.al [] define SMR as another DSR extensions, SMR establishes and utilizes multiple routes of maximally disjoint paths. Providing multiple routes helps minimizing route recovery process and control message overhead. Fahimeh Rookhosh, et.al [8] describes stable tradeoffs between delay and routing load. Scheme uses two routes for each session; the shortest delay route and the one that is maximally disjoint with the shortest delay route. Lianfang Zhang, et.al [] define load-balancing scheme for performance improvement of the multipath routing protocol. End to end delay improve and network resource utilized efficiently. IV. EXPERIMENTAL SETUP & PERFORMANCE METRICS The performance of BMSR protocol is compared with the performance of Dynamic Source Routing protocol (DSR). The BMSR protocol is implemented using the Network Simulator (NS-). NS- provides substantial support for simulation of multipath routing protocols over wired and wireless networks. In this simulation the scenarios consist of mobile nodes moving in a rectangular field of size 5m X 5m, where each node has 5 meter transmission range and having bandwidth of Mbps. Continuous bit rate (CBR) traffic source is used. Balanced Multipath Source Routing (BMSR) protocol is validated in a number of simulated networking scenarios to study the effect of irregular network structure on the performance of the protocol. The source-destination pairs are spread in grid, cross grid and randomly over the network.. The MAC layer protocol is IEEE 8.. The nodes move according to the Random Waypoint. In this simulation, Performance comparison between DSR and BMSR routing protocols is done on parameters such as throughput, packet delivery ratio and end -to-end delay with varying the no of flows and time. The main parameters used in the simulations are summarized in Table. SIMULATION SCENARIO(Table ) Sr. No. Parameters Value MANET Routing Protocols BMSR and DSR Simulator NS- 3 Mobility model Random way point 4 No. of Nodes 5 Application Traffic Type 6 Transmission range Constant Bit Rate-(CBR) 5m 7 Area 5m 5m 8 P a g e N o v e m b e r 8, 3

4 T hroug hpur ISSN CBR data rate Kbit/s 9 Packet Size 48 bytes Standard of IEEE 8. Node Placement Through.tcl file Simulation Time 5 s 3 Qbmsr parameters 4 Balancing setup time I=6,<a<, <b< 5 s Following parameters are evaluated by performing simulation experiments: Packet Delivery Ratio (PDR): Packet delivery ratio is calculated by dividing the total number of data packets received at all the nodes, by the total number of data packets sent out by the CBR sources. Packet delivery ratio forms an important metric for performance evaluation of an ad hoc routing protocol because, given similar scenarios, the number of data packets successfully delivered at the destination depends mainly on path availability, which in turn depends on how effective the underlying routing algorithm is in a mobile scenario. This number represents the effectiveness and the throughput of a protocol in delivering data to the intended receivers within the network. Number of successfully delivered legitimate packets as a ratio of number of generated legitimate packets. PDR Total no of Total no of packet received packet sent Throughput: Throughput is, bits per second delivered to destination, so that unicast network throughput is sum of bits delivered to all destinations over time. It is one of the dimensional parameters of the network which gives the fraction of the channel capacity used for useful transmission selects a destination at the beginning of the simulation, information whether or not data packets correctly delivered to the destinations. Average end-to-end delay: Average end to end delay is the time a data packet takes in traversing from the time it is sent by the source node till the point it is received at the destination node. This metric is a measure of how efficient the underlying routing algorithm is, because primarily the delay depends upon optimality of path chosen, the delay experienced at the interface queues and delay caused by the retransmissions at the physical layer due to collisions. Routing overhead is a major factor affecting the interface queuing delay as well as the retransmissions. Because the higher the routing overhead the delay experienced at the queues will be longer as well as the number of collision would be high. This includes all possible delays caused by buffering during route discovery latency, queuing at the interface queue, retransmission delays at the MAC, and propagation and transfer times. V. RESULT AND ANALYSIS In simulation experiments performed for a number of different network topologies using the ns network simulator.in the first scenario all the simulated nodes are arranged in a grid structure thereafter, the number and position of source-destination pairs was varied to find out the effect of different traffic patterns on the algorithm s performance. Using the above mentioned performance metric BMSR and DSR are compared over the simulated time and all source-destination pairs in use at each simulation. Effect of varying Number of Flows Initially the number of flows is varied as,, 3 and 4. The source and destination nodes are placed in grid and cross grid position (G rid) 3 4 D S R B MS R Figure : Throughput vs. Flows for grid scenario 8 P a g e N o v e m b e r 8, 3

5 Packet Delivery R atio Packet Delivery R atio T hroug hput ISSN F lows Vs T hroug hput (C ros s G rid) D S R B MS R Figure : Throughput vs. Flows for cross grid scenario In this setup, Figure and Figure show that BMSR outperformed DSR. In these experiments, as the number of source-destination pairs increases throughput of both the routing algorithms are decreases. DSR showed the least performance for both the setup. Congested nodes and collisions due to the heavy load in the center of the network caused routes to fail repeatedly. These had to be rediscovered regularly, causing additional overhead of routing control messages. BMSR shows better performance due to its load balancing techniques. F lows Vs Delivery R atio(g rid) D S R B MS R Figure3: Packet Delivery Ratio vs. Flows for grid scenario F lows Vs Delivery R atio (C ros s G rid) D S R B MS R P a g e N o v e m b e r 8, 3

6 E nd to E nd Delay(s ) E nd to E nd Delay(s ) ISSN Figure4: Delivery Ratio vs. Flows for cross grid scenario Fig.3 and Fig 4 shows that BMSR perform better in PDR in comparison of DSR. Packet delivery fraction for BMSR and DSR decreases as no of flows increases. BMSR is multi-path algorithms and follows the alternate route to find the destination. Due to this reason BMSR has less collision of packet and less IFQ overflows as comparision of DSR. Fig. 3 and Fig 4 shows that the delivery ratio of BMSR is 8% and 6% higher than the existing DSR protocol. Fig.5 and Fig. 6 show that delay in BMSR and DSR algorithms. Delay of BMSR is less in comparison of DSR algorithm. As the number of source-destination pairs increases delay of both the routing algorithms is also increases, because of the increase of interference between nodes. BMSR is multi-path algorithm and both follow the alternate route to find the destination. But as the no of flows increase DSR having longer delay because of losing more packets and more retransmission of packets. DSR is using the longer route on average. BMSR shows better results because of its load balancing on the congested nodes. F lows Vs Delay(G rid) D S R B MS R Figure 5: End-to-End Delay vs. Flows for grid scenario F low Vs Delay (C ros s G rid) D S R B MS R F low(#) Figure 6: End-to-End Delay vs. Flows for cross grid scenario Effect of varying Simulation Time In this setup,the source and destination nodes are placed randomly. In this random setup, as the simulation time increases throughput of both the routing algorithms is also increases. This is result of, as the initial route setup build up between source to destination then the performance is increased with the time. But BMSR shows better performance due to its multipath behavior. Figure 7 show that BMSR outperformed DSR. The throughput of BMSR is 6% higher than the existing DSR protocol 83 P a g e N o v e m b e r 8, 3

7 E nd to E nd Delay P ac ket Delivery R atio Throug hput ISSN T ime Vs T hroug hput (R andom) D S R B MS R T ime(s ) Figure 7: Throughput vs. Time for Random scenario Time Vs Delivery R atio(r andom) D S R B MS R T ime(s ) Figure 8: Delivery Ratio vs. Time for Random scenario T ime Vs Delay(R andom) D S R B MS R T ime(s ) Figure 9: End-to-End Delay vs. Time for Random scenario 84 P a g e N o v e m b e r 8, 3

8 ISSN Fig.8 shows that BMSR perform better in PDR in comparison of DSR. Packet delivery fraction for both the protocols increases as simulation time increases. This is because of the fact that as the time increases routes is also build up. BMSR are multi-path algorithms and follow the alternate route to find the destination. Due to this reason as the simulation time increase BMSR shows better PDR as compared to DSR. Fig.9 shows that delay in BMSR algorithm is less in comparison of DSR algorithm. As the simulation time increases delay of both the routing algorithms is decreases due to the fact that initial set up takes some time to stabilize. DSR is unipath algorithm and follow the longer route on average. Number of collision and IFQ overflow are more in DSR as comparision of BMSR. BMSR shows better results because of the load balancing at each node. VI. CONCLUSION In this paper the concept of multipath routing is implemented in wireless ad hoc networks. This paper provide descriptions of a number of multipath routing schemes proposed for wireless ad hoc networks, aiming at showing various strategies of utilizing multiple routings in wireless networks. In this paper, Balanced Multipath Source Routing (BMSR) algorithm is implemented and compared with the existing DSR algorithm. Simulation results show that in all scenarios BMSR gives higher throughput and delivery ratio than DSR. The end to end delay of BMSR protocol is less as comparison of DSR in all the setup. As the number of flows and simulation time increases BMSR distributes the traffic over disjoint multi-path routes to reduce the traffic load on a congested link. Simulation results show that the BMSR algorithm efficiently solves the problem of load balancing, network congestion and fault tolerance. REFERENCES [] Mamoun Hussein Mamoun, A New Reliable Routing Algorithm for MANET, International Journal of Research and Reviews in Computer Science, 3, June, pages [] Schumacher, A., Haanp a a, H., Schaeffer, S.E., Orponen, P.: Load balancing by distributed optimisation in ad hoc networks. In: Proc. of the nd International Conference on Mobile Ad-hoc and Sensor Networks (MSN 6). [3] Jack Tsai, Tim Moors, A Review of Multipath Routing Protocols : From Wireless Ad Hoc to Mesh Networks, Proceedings of ACoRN Early Career Researcher Workshop on Wireless Multihop Networking,Jul 7-8, 6. [4] Sujatha.P.Terdal, V.D.Mytri, A.Damodaram, Load Aware Routing Mechanism for improving Energy Efficiency in Mobile Ad hoc Networks,International Journal of Computer Applications Vol, No 3,November, pp 6-. [5] Sujatha.P.Terdal, V.D.Mytri, A.Damodaram, Multiple Metrics based Load balancing Routing Protocol for Mobile Ad hoc Networks,Proccedings of AH-ICI Kathmandu,IEEE,November 9. [6] Lei Wang et al, Adaptive Multipath Source Routing in Ad hoc Networks,IEEE () [7] Zafar, H. Harle, D. Andonovic, I. Khawaja, Performance evaluation of shortest multipath source routing scheme, Communications. IET, May 9, pages [8] Rookhosh, F.; Haghighat, A.T.; Nickmanesh, S., Disjoint Categories in Low Delay and On-Demand Multipath Dynamic Source Routing Ad hoc Networks, First International Conference on, - Oct. 8, pages. 7-3 [9] David B. Johnson David A. Maltz Josh Broch, DSR: The Dynamic Source Routing Protocol for Multi-Hop Wireless Ad Hoc Networks, Proceedings of INMC 4. 8th International, 4-6 Dec. 4, pages [] Linifang Zhang, Zenghua Zhao, Yantai Shu, Lei Wang, Yang, O.W.W., Load Balancing of Multipath Source Routing in Ad Hoc Networks, Communications,. ICC. IEEE International Conference,, pages vol.5 [] R.Leung, Jilei Liu; E.Poon, A-L.C Chan, Baochun Li, MP-DSR: A QoS-aware Multi-path Dynamic Source Routing Protocol for Wireless Ad-Hoc Networks, Proceedings LCN. 6th Annual IEEE Conference,, pages. 3-4 [] Lee, S.-J., Gerla, M., Split Multipath Routing with Maximally Disjoint Paths in Ad hoc Networks, ICC. IEEE International Conference,, pages vol. [3] Kui Wu Harms, Performance Study of a Multipath Routing Method for Wireless Mobile Ad Hoc Networks, Proceedings Ninth International Symposium,, pages [4] Pham, P. and Perreau, S., Multi-Path Routing Protocol with Load Balancing Policy in Mobile Ad Hoc Routing, IEEE, pp (). [5] Lei Wang, Yantai Shu, Miao Dong, Lianfang Zhang, Yang, O.W.W., Adaptive Multipath Source Routing in Ad Hoc Networks, ICC. IEEE International Conference on ;, pages vol.3 [6] Lei Wang, Lianfang Zhang, Yantai Shu, Miao Dong, "Multipath source routing in wireless ad hoc networks, Proceedings of Canadian Conference on Electrical and Computer Engineering,, pages , vol. 85 P a g e N o v e m b e r 8, 3