Impact of MAC Layer on the Performance of ODMRP, Fisheye, AODV and DSR, Routing Protocols in Mobile Ad hoc Networks

A. Sravani, G. Srinu, and A.Venkataramana Abstract— Mobile Ad hoc Network is an emerging area. Its standards are defined by IETF. MANET is a self generated, self organized and self handled network consisting of collection of independent nodes. MANETs Presents several desirable properties like dynamic topology, Easy of deployment and robustness, which are qualify them as an attractive topic for the research community. Providing QoS routing is a major issue in MANETs. Media Access Control layer plays crucial role in Ad hoc networks. Several routing protocols have already been proposed for MANETs. This paper describes the impact of MAC layer protocols like 802.11 and CSMA on the various routing protocols like AODV, DSR, ODMRP and Fisheye. Numbers of simulation scenarios were carried out by using Glomosim-2.03. The QoS parameters used are Throughput, Delay and PDR. Simulation results found that AODV performs better in 802.11 and CSMA, DSR and ODMRP performs better in only under 802.11.

Keywords— MANET, AODV, DSR, FSR, GloMoSim, ODMRP
I. INTRODUCTION
Wireless communication networks are basically two types as shown in Fig.1. One is infrastructure based and other one is infrastructure less. Infrastructure based is cellular communications whereas infrastructure less is ad hoc networks.

Fig.1 Classification of wireless communication networks

A. Cellular Networks
A Cellular Network is a wireless network distributed over areas called cells, each served by at least one fixed location known as a cell site or base station. The presence of base stations simplifies routing and resource management in a cellular network as the routing decisions are made in a centralized manner with more information about the destination node. The base station is connected to the mobile switching center (MSC) which is, in turn, connected to the public switched telephone network (PSTN). The key requirement for a cellular network is a fixed infrastructure. The current cellular wireless networks are classified as the infrastructure dependent networks (Single-Hop Wireless Networks).
B. Ad hoc Networks
Ad hoc networks are defined as the category of wireless networks that utilize multi-hop relaying and are capable of operating without the support of any fixed infrastructure hence they are also called infrastructure less networks. This system was more than 25 times faster than normal messengers. The use of ad hoc voice communication was used in ancient/tribal societies. The absence of any central coordinator or base station makes the routing a complex one compared to cellular networks. Each node in an ad hoc network acts as both router as well as processing node [12]. Unlike in cellular networks and WLANs, communication in ad hoc networks may take place via multiple wireless hops. There are different types of ad hoc networks like Mobile ad hoc networks (MANET), vehicular ad hoc networks (VANET), sensor networks etc [7].
Ad hoc wireless networks, due to their quick and economically less demanding deployment, find applications in several areas. MANETs are used in a battlefield, communication between soldiers and vehicles can be carried out using ad hoc networks. In such networks, the soldier troops might communicate with each other using hand-held devices. The vehicle mounted devices can be equipped with power sources for “recharging” these mobile devices. Ad hoc networks used in emergency and rescue services, in scenarios such as fire fighting or avalanche rescue operations; a quick deployment of nodes is required. Ad hoc networks can be used in such scenarios for communication between the workers.
Rendering QoS in ad hoc wireless networks can be on a per flow, per link or per node basis [5]. In ad hoc wireless networks, the boundary between the service provider (network) and the user (host) is blurred, thus making it essential to have better coordination among the hosts to achieve QoS. The lack of central coordination and limited resources make the problem.
C. MAC Layer In Mobile Ad-hoc Networks (MANETs), MAC and Network are two major layers that need careful consideration. MAC belongs to second layer in the OSI reference model called Data Link Layer (DLL) to control traffic for regulation. DLL is divided into two sub layers they are LLC-Logical link control and MAC-medium access control [2]. MAC is a Lower part of DLL and it is responsible for Access control while the channel is accessed by multiple users simultaneously. The different MAC protocols are 802.11 DCF, CSMA and MACA [10].
In CSMA (Carrier Sense Multiple Access) protocol, a station wishes to transmit, first it sense (listen) the channel for to check whether it is free or not. If it is free the station can access the channel, otherwise it will wait for a random amount of time then again sense the channel. Unfortunately, CSMA is restricted by two interference mechanisms: the hidden and the exposed terminal problems. In general, Due to hidden terminal collisions will occur and due to exposed terminals unnecessary delay will occur.
IEEE 802.11 uses RTS/CTS mechanism to reduce the problem of hidden and exposed terminal problem 802.11 differ in its requirement of an acknowledgment (ACK) transmission by the receiver after the successful reception of the data packet.
MACA stands for Multiple Access Collision Avoidance. MACA is designed to solve the hidden/exposed terminal problems by regulating the transmitter power, among other things.
II. ROUTING
Routing is the act of moving information from a source to a destination in the network. This is one of the significant challenges in mobile ad hoc networks. Mobile ad hoc networks are characterized by a multi-hop network topology. Efficient routing protocols are used to make a communication path between nodes [3]. Normally, routing protocols are used to satisfy the tolerance of unexpected faults, minimal energy consumption and resilience to increase the traffic loads. In a MANET, routing depends on topology, selection of routers, and specific characteristic in finding the path quickly and efficiently. Infrastructure less networks has no fixed routers. In the network all nodes are moved dynamically [6]. Routing protocols in MANETs are classified into three different categories according to their functionality as shown in the Fig 2.

Fig.2 Classifications of routing protocols
A proactive protocol mandates that nodes in a MANET should keep track of routes to all possible destinations. Reactive protocols employ a lazy approach whereby nodes only discover routes to destinations on demand. Hybrid protocol is presented to overcome the shortcomings of both proactive and reactive routing protocols. Hybrid routing protocol is combination of both proactive and reactive routing protocol [10]. A. ODMRP (On-Demand Multicast Routing Protocol) In the on-demand multicast routing protocol (ODMRP), a mesh is formed by a set of nodes called forwarding nodes which are responsible for forwarding data packets between a source-receiver pair. These forwarding nodes maintain the message-cache which is used to detect duplicate data packets and duplicate control packets. This protocol also applies various on-demand routing techniques to avoid the channel overhead and improve scalability. Since ODMRP uses the soft state approach for maintaining the mesh, it exhibits robustness. But this robustness is at the expense of high control overhead. Another disadvantage is that the same data packet propagates through more than one path to a destination node, resulting in an increased number of data packet transmissions, thereby reducing the multicast efficiency.
B. Fisheye State Routing
The fisheye state routing (FSR) protocol is a generalization of the GSR protocol. FSR uses the fisheye technique to reduce routing overhead. The basic principle behind this technique is the property of a fish’s eye that can capture pixel information with greater accuracy near its eye’s focal point. This accuracy decreases with an increase in the distance from the center of the focal point. This property is translated to routing in ad hoc wireless networks by a node, keeping accurate information about nodes in its local topology, and not-so-accurate information about far-away nodes, the accuracy of the network information decreasing with increasing distance [9]. The main scope of FSR is to determine the number of hops needed to reach the destination.FSR does not trigger any control messages when a link failure is reported. It can be implemented either in network layer or in application layer.

C. Ad hoc On-Demand Distance Vector (AODV) Protocol
AODV is a very simple, efficient and effective reactive routing protocol for Mobile Ad hoc Networks with does not have fixed topology. It can use for both unicast and multicast. AODV minimizes the number of required broadcasts by creating routes on demand. Each node in the network maintains a routing table with the routing information entries to its neighboring nodes, and two separate counters [1]. The concepts of AODV that make it desirable for MANETs with limited bandwidth include Minimal Space Complexity. This protocol defines three types of control messages for route maintenance, Route request, Route reply and Route error [11].
D. Dynamic Source Routing (DSR)
DSR is a distance vector and On Demand routing protocol for MANETs. In DSR the route paths are discovered after source sends a packet to the destination node in the ad hoc network [4]. The source node initially does not have a path to the destination when first packet is sent. DSR also has the capability to handle unidirectional links [8].
III. SIMULATION
A. GloMoSim
Global Mobile Information System Simulator (GloMoSim) is a scalable simulation environment for large wireless and wire line communication networks. GloMoSim uses a parallel discrete-event simulation capability provided by Parsec. GloMoSim simulates networks with up to thousand nodes linked by a heterogeneous communications capability that includes multicast, asymmetric communications using direct satellite broadcasts, multi-hop wireless communications using ad-hoc networking, and traditional Internet protocols. GloMoSim has been designed and built with the primary goal of simulating very large n/w models that can scale up to a million nodes using parallel simulation to significantly reduce the execution time of the simulation model.
B. Simulation Environment
This paper investigates the impact of MAC layer on ODMRP, Fisheye, AODV and DSR routing protocols under MAC protocols CSMA and 802.11. The simulation has been performed using the Global Mobile Information System Simulator (GloMoSim) which provides scalable simulation environment for wireless network systems [8]. The simulation area is 1000 x 1000 square meters. The node density (number of mobile nodes) is 20,40,60,80 and 100. The node aggregation technique is used to give significant benefits to the simulation performance. Traffic sources are Constant Bit Rate (CBR). Mobility model is Random Waypoint. Packet size is 512 bytes data. Simulation time is 300 sec. routing protocols used are AODV, DSR, ODMRP and Fisheye are tested under the MAC protocols 802.11 and CSMA.

TABLE I
SIMULATION ENVIRONMENT Parameter | Description | Simulator | GloMoSim V 2.03 | Routing Protocol | ODMRP,FSR,AODV,DSR | Simulation Time | 300s | Area (sq.m) | 1000 x 1000sqm. | Traffic | CBR | Packet Size | 512 bytes | Bandwidth | 2 Mbps | Nodes | 20, 40,60,80 and 100 | Antenna Type | Omni directional | Transmission range | 250m | Receiver range | 250m | Pause time | 0 sec | Min & Max speed | 1 m/s to 10 m/s | MAC Protocol | 802.11,MACAand CSMA |

IV. RESULTS AND DISCUSSIONS Throughput is the average rate of successful packets delivered over a communication channel. In 802.11 when the network size is 20, throughput of ODMRP is 4096 b/s, whereas for the same scenario the throughput of Fisheye is 775 bits per sec. When the network size increases from 60 to 100, we observed small raise in the throughput i.e., throughput is increased from 4096 to 4110 b/s. The experimental results also state that both 802.11 and CSMA are suitable for AODV, whereas DSR is performing well only in 802.11. The values of throughput are shown in table 2. Variation in throughput is shown in Fig 3 and Fig 5 for 802.11 and CSMA respectively.
TABLE II
DATA VALUES FOR THROUGHPUT End-to-End Delay: End-to-End delay is the average time that packets take to traverse the network. For better performance the delay should be low. Results of end-to-end delay are shown in table 3. End-to-End delay will be decreasing by increasing number of nodes in 802.11 for AODV. In case of CSMA for AODV delay will be increasing with increasing number of nodes. For DSR End-to-End delay is increasing with node density in CSMA, whereas there is no major change in the delay for DSR in 802.11. Variation in end-to-end delay is shown in Fig 4 and Fig 6 for 802.11 and CSMA respectively.
Packet Delivery Ratio: Packet delivery ratio can be defined as the ratio of total number of packets received and total number of packets sent. The PDR is high for ODMRP irrespective of network size, i.e. 100%. Both DSR and AODV has maximum PDR in 802.11, whereas from figure 6 we observed that Packer Delivery Ratio is showing repeated and lot of up and down performances in CSMA.

TABLE III
DATA VALUES FOR E-to-E Delay

Fig.3 Variation in Throughput under 802.11

Fig.4 Variation in Delay under 802.11

Fig.5 Variation in Throughput under CSMA

Fig.6 Variation in Delay under CSMA

V. CONCLUSIONS
In this paper we studied about the MAC layer and various routing protocols in Mobile ad hoc Networks and evaluated the performance of four routing protocols AODV, DSR, ODMRP and Fisheye under MAC layer. In the performance evaluation the QoS metrics used are throughput, end-to-end delay and packet delivery ratio. Any network with high throughput and low delay is preferred. From the experimental results we found that DSR performs better when compared to other routing protocols under MAC layer protocols. For example when the network size is 20, in 802.11 throughput of DSR is 4111 b/s, whereas for the same scenario the throughput of Fisheye is 775 b/s. The experiment was conducted using GloMoSim simulator. This work can be extended to other reactive and proactive routing protocols.
REFERENCES
[1] A.Venkataramana and Dr.S.Pallam Shetty “Analizing the impact of simulation area on the performance of AODV, DSR, AOMDV and DSDV protocols for MANETs under Two-ray and Shadowing propagation models” International Journal of Wireless Communication Networking Technologies Volume 3 No.1 (2014) [2] A.Venkataramana and S.Pallam Shetty “Impact of MAC Layer on AODV and LAR Routing Protocols in MANETs” International Journal of Computer Applications (0975 – 8887) Volume 84 – No 4, December 2013. [3] ManojKumar and Devendra Singh “Performance Analysis of Routing Protocols in MANETs” IJCSMC, Vol. 2, Issue. 6, June 2013. [4] B.V.Ram Naresh Yadav, K. Priyanka and S.Harish “Performance Analysis of Routing Protocols in MANETs” International Journal of Electronics Communication and Computer Engineering Volume 3, Issue 3, ISSN 2249 –071X. [5] B.PraveenKumar ,P.Chandra Sekhar N. Papanna B and.Bharath Bhushan “A Survey on MANET Security Challenges and Routing Protocols” P Chandra Sekhar et al, Int.J.Computer Technology & Applications,Vol 4 (2),248-256 [6] Sachin Dnyandeo Ubarhande “Performance Evolution of AODV and DSR Routing Protocols in MANET Using NS2” International Journal of Scientific & Engineering Research Volume 3, Issue 5, May-2012. [7] B.V.Ram NareshYadav and K.Priyanka “Performance Analysis of Routing Protocols in MANETs” International Journal of Electronics Communication and Computer Engineering Volume 3, Issue 3, ISSN 2249 –071X [8] Robinpreet Kaur and Mritunjay Kumar Rai “A Novel Review on Routing Protocols in MANETs” Undergraduate Academic Research Journal (UARJ), ISSN : 2278 – 1129, Volume-1, Issue-1, 2012 [9] I. Sumaiya Thaseen, and K.Santhi “Performance Analysis of FSR, LAR and ZRP Routing Protocols in MANET” International Journal of Computer Applications (0975 – 8887) Volume 41– No.4, March 2012 [10] C. Siva Ram Murthy and B.S.Manoj “Ad hoc Wireless Networks Architectures and Proocols”, Prentice Hall Communications Engineering and Emerging Technologies Series, 2012. [11] I.Priyadarshini Nimmadala and J.Vasudeva Rao, “Performance Evaluation of Dynamic Routing Protocols in MANETs”, Proceedings of International Conference on Nanoscience, engineering & Advanced Computing (ICNEAC-2011), pp. 551-555, 2011. [12] A.Venkataramana and Dr.S.Pallam Shetty “impact of NTT on the performance of Dymo routing protocol for manets” International Journal of Wireless Communication Networking Technologies Volume 3 No.2, pp. 35-39, 2014.

Acknowledgment Miss Sravani avva and Mr. Srinu G are completed their graduation in 2011 from GCSR College-Rajam Affiliated to Andhra University. They completed their Post Gradation in 2014 from GMR Institute of Technology, Rajam, and Affiliated to JNTUK-Kakinada, Andhra Pradesh.

Mr. Venkataramana Attada born in 1977 received his UG, PG degrees in Computer Science from Andhra University, Visakhapatnam. He also submitted his PhD thesis in Andhra University under the supervision of Prof. S. Pallam Shetty. He is having 15 years of teaching experience. Since 2004 he is working as Associate Professor in Computer Science and Engineering department of GMR Institute of Technology. He is a Life Member of CSI and ISTE. He has presented more than 15 papers in various national and International Journals and Conferences. He guided more than 50 UG and PG projects. He received 3 times best faculty awards in GMR Institute of Technology for his commendable performance in academics. He also received faculty excellence award from Infosys in 2014, under Industry-Institute Partnership program. His research areas include Wireless communication Networks, Mobile Computing, Software Engineering and Data Mining.