A NOVEL APPROACH OF AODV FOR STABILITY AND ENERGY EFFICIENT ROUTING FOR MANET USING IPV6 Shival Chadda Department of Computer Science Lovely Professional University Phagwara, Punjab, India Email: Shival.chadda@gmail.com Mritunjay Kumar Rai Department of Computer Science Lovely Professional University Phagwara, Punjab, India Email: raimritunjay@gmail.com Abstract---In a mobile ad hoc network (MANET), the topology of the network may change rapidly and unexpectedly due to mobility of nodes. Thus, setting up routes that meet high reliability is a very challenging issue. Another important problem in the MANETs is the energy consumption of nodes. This paper presents experiments on the performance and stability of the AODV protocol (Ad hoc On-demand Distance Vector protocol) in multi-hop ad hoc networks. We study the network performance such as throughput, delivery ratio, and end-to end delay. After this experimental study of the problems that may arise in this type of communication and its origins, we conclude that better performance is possible with the modification of some of the protocol s parameters, without modifying the protocol algorithm. Applying these changes, experimental tests show an improvement in the performance of the protocol. Keywords----Mobile Ad-hoc Networks, Routing Protocols, Energy efficiency, Stability, AODV, IPv6. I. INTRODUCTION A mobile ad hoc network lacks a fixed infrastructure and has a dynamically changing topology. The nodes move freely and independently of one another. Ad hoc networks are heavily used in emergency situations where no infrastructure is available, for e.g. battle fields, disaster mitigation etc. The main limitation of ad-hoc systems is the Availability of power. In addition to running the onboard electronics, power consumption is governed by the number of processes and overheads required to maintain connectivity [1]. With the rapid development in wireless communications in recent years, the necessity for sufficient Internet protocol (IP) addresses to meet the demand of mobile devices, as well as flexible communications without infrastructure, are especially considerable. The next-generation IP, Internet Protocol version 6 (IPv6) [1], [2], provides sufficient IP addresses to enable all kinds of devices to connect to the Internet and promotes mobile wireless commerce (m-commerce). The IPv6-enabled network architecture will become the future standard. Additionally, most current mobile devices are equipped with IEEE 802.11 wireless local area network (WLAN) interface cards. IEEE 802.11 WLAN supports two operating modes: infrastructure mode and ad hoc mode. The infrastructure mode requires all mobile devices to directly communicate to the access point (single-hop communication). In the ad hoc mode, mobile devices dynamically form a mobile ad hoc network (MANET) with multi-hop routing. Clearly, the ad hoc mode allows for a more flexible network, but its aim is not to connect to the Internet. In this paper, we address the issue of connecting MANETs to global IPv6 networks while supporting IPv6 mobility with AODV. Much attention has been paid to IP address auto configuration and IPv6 extension for MANETs [3] [5] in recent years. IPv6 auto configuration mechanism [3], [4] allows a node to generate a linklocal IP address. Extension has also been made to be suitable for MANET [5]. However, global connectivity for a mobile node is not supported in [5]. Later on, [6] and [7] address how to provide global connectivity for an IPv6-enabled MANET. In these works, a MANET node can acquire a global IPv6 address from an Internet gateway, and then access to the Internet through the gateway. Routing in MANETs and the IPv6 network is based on existing protocol. The next-generation IP, Internet Protocol version 6 (IPv6) [14], [15], provides sufficient IP addresses to enable all kinds of devices to connect to the Internet and promotes mobile wireless commerce (mcommerce). The IPv6-enabled network architecture will become the future standard. Additionally, most current mobile devices are equipped with IEEE 802.11 wireless local area network (WLAN) interface cards. IEEE 802.11 WLAN supports two operating modes: infrastructure mode and ad hoc mode. 1071
Fig 1: A self-organizing, self-addressing, self-routing IPv6-based MANET. The routing protocols that are available for MANET comprise proactive (table driven), reactive (on demand) and hybrid routing protocols. Popular proactive routing protocols are highly dynamic Destination- Sequenced Distance Vector (DSDV) and Optimized Link State Routing protocol (OLSR) while reactive routing protocols include Ad hoc on demand Distance Vector (AODV) and Dynamic Source Routing (DSR). An example of a hybrid routing protocol is Zone Routing Protocol (ZRP). AODV meets the MANET requirements for dynamic, self-starting, multi-hop routing between participating mobile nodes wishing to establish and maintain an ad hoc network [8]. AODV is an on demand routing protocol, that is, it builds routes between nodes only as desired by source nodes. It maintains these routes as long as they are needed by the sources [9]. Nodes maintain a route cache and use a destination sequence number for each route entry. The fact that a node in AODV seeks information about the network only when needed reduces overhead since nodes do not have to maintain unnecessary route information while the use of a sequence number ensures loop freedom. This paper discusses the effects of packet size on the AODV routing protocol implementation in homogenous and heterogeneous MANET. Rest of the paper is organized as: Section-II, related work. Section-III provides methodology, Section IV provides simulation results and observation and Section-V concludes the paper with future work. II. RELATED WORK other nodes in the network to find route. The RREQ is broadcasted to entire network so every neighbor nodes will receive and process it. All the nodes which receive the RREQ for the first time check its routing table for route. If there is route, it unicasts the RREP to the source, else it will rebroadcast the RREQ to its neighbors. If the RREQ is not the first time, it will silently discard the RREQ and If the node is the destination, it unicasts the RREQ to the source. When the source node gets the RREP, it starts sending the packet to the destination. When a route has been established, it is being maintained by the source node as long as the route is needed. If any of the intermediate nodes losses connectivity, the RERR will be sent to the source and the source sends packets through the alternate paths or it will restart the route discovery process. Thus the route discovery process leads to energy consumption in all nodes. Fig 2: Route discovery process AODV specifies two different ways in which a link break can be detected. Either all nodes regularly broadcast a hello message to its one-hop neighbors, which makes it possible for them to verify the link operation, or it is detected by a link signaling mechanism when the link is used. When a link break is detected the end nodes (source and destination) are informed and it is up to them to find a new path. To reduce the route request broadcast storms the route discovery can be performed using an expanding ring search. In an expanding ring search the route discovery area is limited by the Time to live (TTL) field in the IP header. A sequence of route requests are performed with increasing TTL until the destination is found or a set limit is reached. If a state route to the destination is available that hop count can be used as an initial TTL limit. There has been significant work on routing in MANETs [3] [4]. AODV is an on-demand driven protocol which finds routes between a source destination pair only when it is required. Traditional AODV extensively uses blind flooding for forwarding the RREQ packets from source to all 1072
III. METHODOLOGY The tests were carried out using the AODV protocol using Opnet 14.5.We apply changes in the AODV parameters in different scenarios. We study the network performance such as throughput, delivery ratio, and end-to end delay. A. Performance Metrics In order to evaluate the performances of three MANET protocols, several metrics need to consider. These metrics reflect how efficiently the data is delivered. In epidemic routing, multiple copies may be delivered to the destination. According to the literatures [10], [11], [12] and [13], some of these metrics are suggested by the MANET working group for routing protocol evaluation. (a) Packet Delivery Ratio The ratio between the number of packets originated by the application layer CBR sources and the number of packets received by the CBR sink at the final destination. (b) Average End-to-end Delay This includes all the possible delays caused by buffering during route discovery latency, queuing at the interface queue, retransmission delays at the MAC, and propagation and transfer times. (c) Packet Dropped The routers might fail to deliver or drop some packets or data if they arrive when their buffer are already full. Some, none, or all the packets or data might be dropped, depending on the state of the network, and it is impossible to determine what will happen in advance. (d) Routing Load The total number of routing packets transmitted during the simulation. For packets sent over multiple hops, each transmission of the packet or each hop counts as one transmission. (e) Throughput The total successfully received packet to the destination. In the other words, the aggregate throughput is the sum of the data rates that are delivered to all nodes in a network. Table 1: Simulation Settings Parameter Value Simulation time 1000 sec Number of nodes 20,50,100 Data rate 2 Mbps Environment size 100*100 meters Traffic type Constant Bit Rate (CBR) Minimum Speed 0 sec Maximum Speed 10,15,20 Packet size 512 Network protocol IP Transport Protocol TCP Propagation Model Random Way Point Model MAC protocol 802.11 B. Simulation Parameters The simulation parameters that have been used can be divided to two types that are: general simulation parameters and simulation parameters for every protocol. All of this parameters are common parameters and been used by many researcher. We do some modification in these parameters and simulation shows better results. We have used network simulator OPNET for simulation. We simulated network in order to compare performance of routing protocols between AODV and improved AODV ipv6. We have used average throughput as performance parameters while varying various network parameter such as number of nodes and TTL parameters, node speed in 100*100 meter environment. IV SIMULATION RESULTS AND OBSERVATIONS We have analyzed the performance of a AODV by creating different scenario in Opnet Modeler 14.5. Traffic of the AODV is evaluated in presence source and destination on the same distance of both scenarios. For the experimental results 20, 50,100 nodes are configured in these scenarios. Two mobility nodes are configured in both scenarios to represent mobile Ad-hoc network. In these scenarios we give IP address of source and destination node. Other nodes having auto IP We have done simulation work for our approach for AODV in OPNET 14.5. The simulation result shows that our approach gives more efficient than the existing. 1073
We have three scenarios as shown in the figure and we apply our approach on all these according to the number of nodes. The simulation shows better results and also as number of nodes increasing throughput increases. the network is increase as compare to fewer nodes used in network with our approach of using ipv6 and changing parameters. A Simulation Environments (a) 20 nodes (a) 20 nodes (a) 50 nodes (b) 50 nodes (c ) 100 nodes (c) 100 nodes Fig 3: OPNET simulate in the area of 100x100 m 2 B. Throughput Throughput is number of bits transmitted between source and destination per unit time. To be able to relate this number to the desired outcome the throughput is presented as a ratio between transmitted packets and delivered packets. Simulation results show that in each scenario our approach with ipv6 gives better result than the conventional AODV. In these scenarios routing traffic sent by AODV in bit/sec is gathered. In these scenarios we analyzed the when we used large node in network throughput of Fig 4: Simulation of Average WLAN Throughput in the area of 100x100 m 2 C. Average end to end delay There is minor improvement in average end to end delay as simulation result shows. Fig 5: Simulation of Average end to end delay 1074
D. Route Discovery Time Route discovery time decreases as nodes increases say when we used large nodes in network routing load also increase in that network. F. Average Packet Dropped (a) 20 nodes Fig 8: Simulation of Average WLAN Load Average packed dropped as simulation result shows with increasing number of nodes. V CONCLUSION AND FUTURE WORK (b) 50 nodes Fig 6: Simulation of Route Discovery Time E. Average WLAN Load (a) 50 nodes In simulation the analysis of AODV with ipv6 and changing parameters of using different network size in Opnet 14.5 gives improved result. But throughput and routing load is preferable in large network size. We concluded our approach AODV works better than existing AODV and giving more lifetimes to the network. We observe that an increase in network size and number of nodes has similar impact on all protocols under various environments.. In this simulation study, we have not used large no of nodes and simulation time was 1000s. Increasing both of them will increase computational time which was limited due to various reasons. Thus, in future we will carry out more vigorous simulation so as to gain better understanding of such networks and subsequently helps in development of new protocols or modification in existing protocols.. REFERENCES [1] S. Deering and R. Hinden, Internet protocol, version 6 (IPv6) specification, IETF, RFC 2460, 1998. [2] Hinden, R. Hindon, and S. Deering, Internet protocol version 6 addressing architecture, IETF, RFC 3513, 2003. [3] T. Narten, E. Nordmark, and W. Simpson, Neighbor discovery for IP version 6 (IPv6), IETF, RFC2461, 1998. (b) 100 nodes Fig 7: Simulation of Average WLAN Load In all scenarios we observed that routing load is decreases in improved AODV parameters with increase of traffic and ipv6. In other words we [4] S. Thomson and T. Narten, IPv6 stateless address autoconfiguration, IETF, RFC 2462, 1998. [5] C. Perkins, J. Malinen, R. Wakikawa, E. Belding-Royer, and Y. Sun, IP address autoconfiguration for ad hoc networks, IETF Internet Draft, draft-ietf-manet-autoconf-01.txt, 2001. 1075
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