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ISSN:2249-5789 Prof.Santosh Deshpande, International Journal of Computer Science & Communication Networks,Vol 6(3),175-180 Behavioural Analysis of MANET Protocol under Specific Conditions Prof.Santosh Deshpande H.O.D Computer Department MES IMCC, Pune (SPPU University) sarvesh_santosh2003@yahoo.com Abstract The paper presents the results of a detailed packet-level simulation comparing three multi-hop wireless ad hoc network routing protocols under the load of different probability distributions, that cover a range of design choices having different protocol viz. AODV,DSR and GRP. We have extended the OPNET network simulator to accurately model the MAC and physical-layer behaviour of the IEEE 802.11 wireless LAN standard, including a realistic wireless transmission channel model. Simulation of 100 mobile nodes has been carried out and the performance optimization is determined. Key words: Simulation, Opnet, Wireless, Statistical probability distribution, IEEE802.11, throughput, delay, retransmission attempt, load, protocol, MAC, LAN. 1. Introduction Ad-hoc wireless network is that network where no communication is present, in such network; each mobile node operates not only as a host but also as router. Mobile nodes in the network may not be within range of each other, communication of these nodes perform by discovering “multi-hop” paths through the network to other nodes. This type of network is some time called infrastructure less network [1]. Some examples of the possible uses of ad hoc networking are students using laptop computers to participate in an interactive lecture, business associates sharing information during a meeting, soldiers relaying information for situational awareness on the battlefield [2, 3]. Many different protocols have been proposed to solve the multi hop routing problem in ad hoc networks, each based on different assumptions and intuitions. Mobile Ad hoc Networks (MANETs)[1] are an emerging technology that allows establishing an instant communication network for civilian and military applications, without relying on preexisting fixed network infrastructure. The nodes in a MANET can dynamically join and leave the network, frequently, often without warming, and possibly without disruption to other nodes’ communication. Each node in the network also acts IJCSCN | June-July 2016 Available online@www.ijcscn.com as router, forwarding data packet for other nodes. A central challenge in design of Ad hoc network is the development of dynamic routing protocols that can effectively find the route between two communicating nodes. The routing protocol must be able to keep up with the high degree of node mobility that often changes the topology drastically and unpredictably. The current Mobile Ad Hoc Network (MANET) [2] paradigm as described by the Internet Engineering Task Force (IETF) MANET work group. Routing algorithms are often difficult to formalize into mathematics; they are instead tested using extensive simulation. A large amount of work has been done in the area of energy efficient routing. This approach attempts to maximize network lifetime by routing through paths, which use the least amount of energy relative to each node. Now a day, more attention has been given to use specific network parameters while specifying routing matrixes. Routing matrixes includes delay of network, link capacity, link stability or identifying low mobility nodes. These schemes are generally based on previous work, which is then enhanced with the new matrix. The paper is providing a realistic, quantitative analysis comparing the performance of a variety of multi-hop wireless ad hoc network routing protocols. We present results of detailed simulations showing the relative performance of three recently proposed ad hoc routing protocols: AODV [4], DSR [6] and GRP [7]. Our results in this paper are based on simulations of an ad hoc network of 100 wireless mobile nodes moving about and communicating with each other. We analyse the performance of each protocol and explain the design choices that account for their performance. The section 2 of the paper describes the different types of protocols used in the simulation. The section 3 has given description statistical probability distributions and section 4 has given information about the design model. The performance analysis is describes in section 4 and the section 5 has summaries with conclusion of the paper. 175 ISSN:2249-5789 Prof.Santosh Deshpande, International Journal of Computer Science & Communication Networks,Vol 6(3),175-180 2. Description of Protocols 2.1 Ad Hoc on Demand Distance Vector (AODV) [4] AODV discovers routes on demand basis. It uses routing table to maintain routing information, one entry per destination. RREP packet is used to replies back to the source and, subsequently, to route data packets to the destination. AODV uses sequence numbers to maintain at each destination to determine routing information and to prevent routing loops [4]. AODV working on timer- based states in each node. A routing table entry is expired if not used recently. If node link is broken, the all predecessor nodes forward the RERR packets, to effectively erasing all routes using broken link. AODV uses expanding ring search technique initially to discover routes to an unknown destination. AODV algorithm has the ability to quickly adapt to dynamic link conditions with low processing and memory overhead. AODV offers low network utilization and uses destination sequence number to ensure loop freedom AODV keeps the following information with each route table entry. a) Destination IP address (IP address for the destination node), b) Destination sequence number, c) Valid destination sequence number flag, d) Network interface, e) Hop count, that is, number of hops required to reach the destination, f) Next hop (the next valid node that did not re broadcast the RREQ message), g) List of precursor, h) Life time, that is, expiration or deletion time of a route. 2.2 Dynamic Source Routing (DSR) [12] The Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol designed specifically for use in multi-hop wireless Ad-hoc networks of mobile nodes. Using DSR, the network is completely self-organizing and selfconfiguring, requiring no existing network infrastructure or administration. When two nodes are not directly in transmission range, then in between nodes help to forward massage by using multi-hop process. As nodes in the network move about or join or leave the network, and as wireless transmission conditions such as sources of interference change, all routing is automatically determined and maintained by the DSR routing protocol. Since the number or sequence of intermediate hops needed to reach any destination may change at IJCSCN | June-July 2016 Available online@www.ijcscn.com any time, the resulting network topology may be quite rich and rapidly changing. In designing DSR, we require to create a routing protocol that has very low overhead and it is able to react very quickly to changes in the network. The DSR protocol provides highly reactive service in order to help in ensuring successful delivery of data packets in spite of node movement or other changes in network conditions. The DSR protocol is composed of two main mechanisms that work together to allow the discovery and maintenance of source routes in the ad hoc network. 2.3 Geographic Routing Protocol (GRP) [14] Geographic Routing Protocol always follows the shortest distance for reaching destination. A node maintains its list of neighbour nodes by periodically sending hello messages. If nodes do not receive any hello message from the neighbouring nodes, it assumes that the link to the neighbour node is lost. To bootstrap the network, all nodes initially initiate full flooding throughout the network. The positions of other nodes have been determined through flooding. When a node moves more than the specified distance, it sends out a flooding message with its new position. To reduce the overhead caused by flooding updates, GRP uses the fuzzy routing. Each node that receives the data packet considers which of its neighbour node is closest to the destination and picks that neighbour to forward the packet. To avoid loops, neighbour nodes that have already been traversed are omitted. Sometimes while forwarding packets based on shortest distance, it can reach to blocked routes where there are no new nodes to forward the packet to. Backtracking is a mechanism where the packet is returned to the previous hop where a new next hop selection can be made. 3. Probability Distributions 3.1 Binomial Distribution [17, 18] Binomial distribution is discrete probability distribution A random variable x is said to follow a Binomial if it assumes only non – negative vales and its probability mass function is given by p(x, nk) P(x) = /x! ; x= 0, 1, 2, 3… =0 otherwise 3.2 Gamma Distribution [17, 19, 20] Gamma distribution is continuous distribution. The theoretical basis for the gamma distribution is the 176 ISSN:2249-5789 Prof.Santosh Deshpande, International Journal of Computer Science & Communication Networks,Vol 6(3),175-180 gamma function. It is a mathematical function defined in terms of an interval. The Gamma function Γ defined by Γ (λ) = ∫ z λ-1 e-z dz λ > 0, integral between 0 to ∞. A random variable X is said to have a gamma distribution with parameter λ > 0 if its probability distribution function is given by; f(x) = (e-xx λ-1)/ Γ(λ) ; λ > 0, 0< x < ∞ The gamma distribution represents the sum of n exponentially distributed random variables. Both the shape and scale parameters can have noninteger values. 3.3 Exponential Distribution [21, 22] The exponential distribution is one of the most significant and widely used distributions in statistical practice. It possesses several important statistical properties and yet exhibits great mathematical tractability. A random variable X is said to have an exponential distribution with parameter θ>0, if its probability density function is given by; for , where is a gamma function 3.5 Normal Distribution [24, 25] The normal distribution is pattern for the distribution of a set of data which follows a bell shaped curve. This distribution is sometimes called the Gaussian distribution in honour of Carl Friedrich Gauss, a famous mathematician. The bell shaped curve has several properties: a) The curve concentrated in the center and decreases on either side. This means that the data has less of a tendency to produce unusually extreme values, compared to some other distributions. b) The bell shaped curve is symmetric. This tells you that the probability of deviations from the mean is comparable in either direction. The distribution of a random variable X for which the probability density function f(x) is given by f(x) = θ e-θx , x ≥ 0 =0 otherwise. 3.4 Chi-Square Distribution [23] If have normal independent distributions with mean 0 and variance 1, then The parameters μ and σ2 are respectively the mean and variance of the distribution. The distribution is denoted by N(μ, σ2). If the random variable X has such a distribution, then this is denoted by X ∼ N(μ, σ2) and the random variable may be referred to as a normal variable. 4.0 Model Description is distributed as with degrees of freedom. This makes a distribution a gamma distribution with and , where is the number of degrees of freedom. More generally, if are independently distributed according to distribution with , , ..., degrees of freedom, then is distributed according to with degrees of freedom. The probability density function for the distribution with degrees of freedom is given by IJCSCN | June-July 2016 Available online@www.ijcscn.com We have constructed a detailed simulation model that accurately follows the details of Wireless routing protocol on random waypoint model. We have performed simulation for specifically inter arrival time probability distributions. In order to verify the accuracy of our model, we set up the simulator to represent a real system for which sufficient details are available in the literature. Our simulation model is based on OPNET 14.5 simulator. The effective parameters with their optimized values are reported here for each of different set of simulation. 177 ISSN:2249-5789 Prof.Santosh Deshpande, International Journal of Computer Science & Communication Networks,Vol 6(3),175-180 Figure 4.1 Ad hoc Wireless Network We developed a detailed simulation model based on OPNET 14.5 which is implementing Ad-hoc routing protocols (DSR, AODV, and GRP) and closely watching the performance of each protocol. Our simulation model was based on the 100 wireless nodes forming Ad hoc network. Nodes are moving within the network area for 3600 seconds of simulation time. As shown in the figure 4.1, wireless network consist of Wireless LAN workstations. The "wlan_wkstn" model can be configured to run any MANET routing protocols. 5.0 Performance Analysis of Protocol We have conducted relative performance study of Ad hoc routing protocols through simulation model using Optimize Network Engineering Tool (OPNET 14.5) simulator to carry out simulation. Performance of simulation has analysis based on following matrix. a) Figure 5.1 Wireless LAN Throughputs It selects a destination at the beginning of the simulation. As shown in the figure 5.1, AODV performance far better than DSR and GRP under the load of probability distributions. On an average LAN throughput (bits/sec) of AODV protocol is 14,000,000 and average throughput of DSR and GRP are less than 2,000,000 (bits/sec). DSR protocol is maintaining the information about all neighbouring nodes before sending the packets to nodes. Because of this property of DSR protocol performance of DSR under different probability distribution is identical. Geographic Routing Protocol (GRP) always follows the shortest distance for reaching destination. A node maintains list of its neighbour nodes by periodically sending hello messages. 5.2 Wireless LAN Retransmission Attempts (packets) Wireless LAN Throughput b) Retransmitting attempts c) End to End delay d) Wireless LAN Data Dropped 5.1 Wireless LAN Throughput As shown in the figure 5.1 we have design three scenarios. First scenario is testing the performance of AODV protocol with the load of statistics distribution. Second scenario is testing the performance of DSR routing protocol and third scenario is based on GRP protocol. It is one of the dimensional parameters of the network which gives the fraction of the channel capacity used for useful transmission. IJCSCN | June-July 2016 Available online@www.ijcscn.com Figure 5.2 Wireless LAN Retransmission Attempts (packets) As shown in the figure 5.2, it is observed that AODV perform retransmission attempts was almost identical throughout the simulation under the load of all statistical distributions. It is further observed that, AODV retransmitted 1.2 packets under the load of probability distributions at one particular time during the simulation. As shown in the figure 5.1, DSR protocol was retransmitted on an average one packet per transmission under the load of probability distributions. As shown in the figure 178 ISSN:2249-5789 Prof.Santosh Deshpande, International Journal of Computer Science & Communication Networks,Vol 6(3),175-180 5.1, GRP retransmitted zero number of packets throughout the simulation under the load of statistical probability distributions. 5.3 Wireless LAN Data Dropped Figure 5.4 Wireless LAN Delay 6. Conclusion Figure 5.3 Wireless LAN Data Dropped This statistic reports the number of the higher layer packets that are dropped because the MAC couldn't receive any ACKs for the retransmissions of those packets or their fragments. As shown in the figure 5.3 Wireless LAN data dropped is same for DSR and AODV protocol throughout the simulation time. As shown in the figure 5.3, it is observed that AODV under the load of Chi-square distribution and Exponential distribution data drop was highest throughout the simulation time. When maximum data drop was observed under the load of Exponential and Chi-square distributions then also throughput was good. DSR and AODV data dropped was on an average 6000 bits/sec under the statistical distributions. GRP protocol had shown zero data drop throughout this simulation experiment. 5.4 Wireless LAN Delay Figure 5.4 shows that end-to-end delay of DSR protocol. It was steady and highest throughout simulation under the load of probability distributions as compared to AODV and GRP protocol. As shown in the figure 5.4, it is observed that End-to-End delay of AODV was around 15 sec per transmission under the load of almost all probability distributions. GRP protocol had minimum End-to-End delay and maximum throughput under the load of Gamma distribution. GRP protocol had shown minimum End-to-End delay under the load of probability distribution i.e. below 0.0005 sec. IJCSCN | June-July 2016 Available online@www.ijcscn.com A MANET simulation models were developed for different Wireless routing protocols i.e. AODV, DSR and GRP. The performance of simulation models was observed and discussed in above sections. Based on the performance of routing protocols following are the by and large observations. a) The AODV performance is best in terms of throughput as compared to the DSR and GRP. b) GRP has shown zero data dropped, zero delay and zero retransmission attempts. c) DSR has shown maximum delay throughout the simulation. d) AODV and DSR have shown equal number of data dropped under the load of probability distributions. 7. References [1] National Science Foundation. Research priorities in wireless and mobile communications and networking: Report of a workshop held March 24–26, 1997, Airlie House, Virginia. Available at http://www.cise.nsf.gov /anir/ww.html. [2] Barry M. Leiner, Robert J. Ruth, and Ambatipudi R. Sastry. Goals and challenges of the DARPA GloMo program. IEEE Personal Communications, 3(6):34–43. [3] David B. Johnson. Routing in ad hoc networks of mobile hosts. In Proceedings of the IEEE Workshop on Mobile Computing Systems and Applications, pages 158–163, [4] C. Perkins, E. 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