Ad-hoc Routing Protocols

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: “Comparison and Performance of Ad-hoc Routing Protocols”

Abstract

As we know that the field of wireless technology has taken more desirability and interest in this world. The principal theme of this project is to provides a practical achievements and to learn the functioning and operation of Ad-hoc wireless network also, with this to determined the outcomes by utilizing the various distinctive Ad-hoc routing protocols that has a enormous importance in communication among of mobile nodes. To get done the mission on OPNET modeller , we are using three various dissimilar Ad-hoc routing protocols namely Optimised link state routing protocol ,distance source routing and Ad-hoc on-demand distance vector routing protocols.

My endeavour is to focusing on the presentation and evaluation analysis of these protocol which are depend upon on three various dissimilar criterions, as far the research I have done the comparison of Data Dropped, End to End delay and in the last Throughput in my whole project. The victorious achievement of this simulation analyze that, by selecting these distinctive Ad-hoc routing protocol and analyze that which one of them give better throughput however, be short of lessening in general delay in the network because of its functioning environment. It is verify that the final outcomes of Optimised link state routing protocol is extra consistent and proficient as relative to Dynamic Source Routing and Ad hoc on-demand Distance Vector due to less significant overall data dropped. This verify that and also we have studied in many books regarding the automatic protocol that each time, it take alternating way to approach the end station node and that accessible in reactive routing protocols therefore, it takes a substitute way each time to arrive at the receiver end when the primary connection failure.

Finally, I have talk about the issues concerned with the project, One of my main motive is to make this report to superpose not only the practical viewers, but the non practical viewers as well as. Particularly the administration of fresh companies who needs to have a look into this expertise and know the initiative that how comparison of Ad-Hoc routing protocol is proficient of.

CHAPTER ONE: Introduction

1.1 Introduction

Mobility is playing a very important role in the present era due to the non stationary behaviour of the end devices and the rapid changes in technologies. The focus of this project is the study of Ad-hoc atmosphere and certain parameters such as End-To-End delay, Throughput and Data dropped effecting data transmission in medium to large size networks.

In Ad-hoc network atmosphere each node behaves and operates as a router, sending information to other node. All Nodes/Stations are communicating without any network infrastructure. In this project OPNET 14.5 has been used for Ad-hoc Network simulation, which is the most popular and advanced simulation tool used by communication expert all over the world. I used this software to examine the behaviour and operation of protocols such as Optimized Link State Routing protocol, Dynamic Source Routing protocol and Ad-hoc On-Demand Distance Vector protocol etc in Ad-hoc Network environment.

The most Significant part of this project report is the comparison performance of Ad-hoc routing protocols results analysis taken from different scenarios according to a variable number of nodes in each scenario and changing their location in order to examine thoroughly which protocol perform well in dissimilar scenarios situation.

1.2 Aims of the project

* To study and examine the initiative that how routing is performed with various dissimilar Ad-hoc routing protocols in Ad-hoc Networks.

* Assessment of Ad-hoc routing protocols by Capturing Mobile Ad-hoc Network illustration and do simulation using OPNET 14.5 Modeller.

* Simulating system with changing the size of Network i.e. increasing the number of mobile stations.

* Evaluate the end results and examine that which protocol is working well in different scenarios conditions as compare to other protocols.

1.3 Objectives of the project:

* Designing and creating Mobile Ad-hoc Network for the performance based comparison between different routing protocols.

* Comparison of the final results of Ad-hoc routing protocol performance based on dissimilar consideration such as Data dropped, Throughput and End-to-End delay.

* After simulation results analysis, exploring that which protocol perform better in dissimilar scenarios conditions.

1.4 Project Outlines
Chapter Two: Ad-hoc Wireless Networks

This chapter explores the concept of Ad-hoc Wireless Networks as well as its working and operation. In addition this chapter emphasize on most common issue with Ad-hoc Wireless Networks such as routing, Privacy and security, transport layer protocol performance, Scalability and in the last multicasting. Finally some of the areas are described where Ad-hoc wireless Network is an operational such as Military services, emergency situations, Wireless Mesh Network and Wireless sensor Network etc.

Chapter Three: Routing Protocol for Ad-hoc Wireless Networks

In this particular chapter we will talk about the certain field of requirements that are referred by Mobile Ad-hoc routing protocols for example Accessibility of Low-Bandwidth, mobility and confined resources Accessibility. We will discuss some qualities of the routing protocols for example their working, benefits and drawbacks as well explained in this chapter.

Chapter Forth: Simulation results & discussions

In this section we will explain the plan simulation that performs on three various dissimilar situation circumstances in OPNET modeller 14.5. In these 3 situations they have contradictory no of mobile station & every station without stopping shifting their position due to time. In these situations dissimilar raw packets will construct in the network and the address of end station modify with respect to time. Further we will discuss the final outcomes of Dynamic source routing protocol, Ad-hoc on-demand distance vector routing protocol and Optimized link state routing protocol and for getting the result we will run this simulation for 30 min to get the better results.

Chapter Five: Conclusion & Suggestion for Future Work

The conclusion of this chapter shows end results that depend upon 3 dissimilar situation methods to analyze that which protocols is the best Ad-hoc routing protocol that perform better in these distinctive situation conditions. It also shows those areas of activity or interest where future work is needed. In order to examine the further presentation of Ad-hoc routing protocols that depend upon dissimilar methods for example Data Dropped, throughput and End-to-End Delay.

1.5 Requirements of Hardware and Software Programs:

* Desktop / Laptop computer

* OPNET 14.5 ( Simulation Tool )

* Operating Systems ( Window XP, Window 2000, Windows Vista )

* Internet connection

Tasks

Explanation

Length

Weeks

1

Introduction and Background study of Ad-hoc Network.

2/12/09 To 12/01/10

6

2

Depth Study of Ad-hoc Routing Protocols.

13/01/10 To 09/02/10

4

3

Formation of Ad-hoc Network situation circumstance through the simulator.

10/02/10 To 09/03/10

4

4

Changing the parameters and run the simulation

10/03/10 To 23/03/10

2

5

Analysis of the final outcomes (Results)

24/03/10 To 06/04/10

2

6

Practical report writing

07/04/10 To 20/04/10

2

Table 1-1: Task completion List

1.6 Work planned Chart

CHAPTER TWO: Ad-Hoc Wireless Network

2.1 Overview

Ad-hoc Wireless Network employs transmission method followed in Multi-hope systems [2]. This concept was come in to approach by the ruler of Persia name called Darius I (522-486 BC) [2]. He initiated the inventive transmission system for the purpose of sending e-mails and information to distant regions of his state from the capital. The Ad-hoc Network idea was also used in ancient time for transmission of speech data. ALOHAnet [4]; was introduced in 1970 by the Norman Abramson and associate researcher of his team at the Hawaii University. The aim of this creation was to link only Hawaii universities, while the fundamental idea was to implement such a system capable of allowing devices to negotiate for accessing general resource. Since, Aloha successfully sent and received messages within a Single Radio hope system [3]. After a victorious positive response and gratitude of ALOHA, Ethernet & Packet Radio Network (PRNET) two distinctive networks were introduced. PRNET was supported by Defence Advanced Research Project Agency (DARPA) [3]. Both ALOHAnet and PRNET made it possible by sending/receiving data on multiple radio hops system instead of single. PRNET was developed for military purposes, initially PRNET was operational in centralised environment where devices access centralised resources but later on it was successfully implemented in multi hops shared environment. It combines the techniques of ALOHAnet & Carrier scenes multiple access (CSMA) for accessing shared radio channel and resources [2]. The reason of PRNET success was easy installation, self configuration and dynamic routing protocol support. Apart from the success, there were some issues with PRNET such as difficulty in obtaining topology information, flow control errors etc. The PRNET also introduced Survivable Radio Networks (SURAN) a new concept of information sharing over infrastructure-less networks, later on it was extended by DARPA on multi hops system [2]. The aim was the survival of network in case link or station failure occurs.

In 1980, lots of people focused and worked on information sharing over infrastructure-less wireless networks and thus become conscious to the requirement for a standard criterion. In the supervision of Internet Engineering Task Force (IETF) they developed a model named MOBILE AD-HOC NETWORK [5] (MANET). It is also sometimes called Mesh Networks [31].

After the introduction and implementation of accessing resources on infrastructure-less multi-hop radio network. “In 1994 Ericson a Swedish company made an effort for the development of short range, less power utilization and less complex hardware implementation referred to as Bluetooth [2]”. The major short come with this proposal was power consumption in infrastructure-less network, where devices use more power while they are sending and receiving information [2].

yet the implementation of infrastructure-less Ad hoc network where each device sending and receiving information without having any infrastructure, the advancement in wireless networks make it possible to implement the same concept in an Infrastructure based system. In infrastructure based network devices are able to send and receive data the same way as they do in infrastructure-less networks. The Multi-hop cellular networks (MCNs) [5] and {SOPRANO} stand for Self organizing Packet Radio Ad-hoc network [2] are the examples of infrastructure based network where nodes are able to exchange data over infrastructural system. “The Recent development in mobile Ad-hoc networks, work is going on to give facilities for real-time application and provision of QoS (Quality of Service) with load balancing”.

2.2 Ad-Hoc Wireless Network/Cellular Wireless Network

Ad-Hoc wireless network and cellular wireless network are the two wireless network systems. 2.1 describes the Cellular Wireless Network while 2.2 describes the Ad-hoc Wireless Network. Both are different in terms of network operation, in Cellular wireless Network mobile stations are connected with a central device known as (BS) Base Stations; the neighbouring base stations exchanged information with each other which simplifies routing and resource management in a centralised cellular Wireless Network [2].

On the other hand in Ad-hoc Wireless Network each station exchange information with the other stations in a distributed manner, hence each station operates as a client as well a router. This way mobile stations perform a complex operation as compare to stations in Cellular wireless networks and also resource management and routing is more complex and complicated [2].

2.3 Ad-Hoc Wireless Networks Issues

There are some issues effecting Ad-hoc Wireless Networks, which must be taken into consideration prior to the deployment of any wireless network system. A few of them important and critical issues are described below [2].

* Routing

* Privacy and Security

· Transport layer protocol Performances

* Scalability

* Multicasting

2.3.1 Routing

Routing is a technique used to find out route (path) towards the destination nodes, normally devices (Source, Intermediate & Destination) exchanges routing table with each others. The routing table contains routes information towards the destination nodes from source node. In Ad-Hoc wireless mobile networks paths are continuously changing due to mobility, therefore devices must maintain up-to-date routing table otherwise they would not be able to communicate with other nodes. Some efficient routing protocols are needed to keep updated routing table according to changes occurs in the network. Link state and Distance-vector routing protocols performs routing process but their response is not so much efficient according to the swift changes in the system network so there is a need for new routing protocols [3].

2.3.2 Privacy and Security

Security and Privacy is the most important issue in Ad-hoc Wireless Networks because all stations communicate directly with each other without having centralized system. Hence some major precautionary steps are required to ensure that only authenticated user can access network. “Wireless network is more vulnerable to attacks as compare to wire line network due to an unguided nature of wireless medium. Therefore wireless network is affected by passive and active attacks. In Passive attack [2] hacker obtain the transacted information from ongoing communication without interrupt existing operation, while in active attack hacker dynamically intercept ongoing communication and try to make data corrupted”.

2.3.3 Transport layer protocol Performances

The performances and presentation of transport layer is based on the operation of two protocols called Transfer control protocol (TCP) and User data protocol (UDP).

TCP is also called connection oriented protocol means a connection (session) is established between source and destination before data transmission. After connection being established both sender and receiver can send and receive data segments. TCP is a reliable protocol, which guaranteed a safe data segment arrival at the destination by maintaining sequence numbers. TCP is also able to maintain flow control when congestion is detected TCP reduces its window size by sending limited number of segment which reduces congestion. In Ad hoc wireless network, performance of TCP is not satisfactory because of the retransmission of segments due to the mobility of nodes [2].

On the other hand UDP is a connectionless protocol means source node can send data segments to destination node without any prior connection establishment. UDP is unreliable protocol, does not guaranteed a safe arrival of data segment at the destination because it does not maintain segments sequencing. UDP does not maintain flow control due to its unreliable nature, therefore it cannot detect congestion. This act of UDP degrades Ad-hoc Wireless Network performance [2].

2.3.4 Scalability

Now a days the number of nodes in Ad-hoc Wireless Network is not growing as compare with the Internet and even communication of data is take place at very short distance. Thus a limited number of mobile stations communicate smoothly without effecting throughput. As the number of node grows and cross certain limit, then data throughout in Ad-hoc wireless network is badly affected. Scalability has more consequences in Ad-hoc network when any of the links goes down then it is very difficult to find an alternative route, therefore this brings data drop, delay and jitter (delay variability) inside network.

2.3.5 Multicasting

The rapid growth of the internet and the demand for new services, allowing large number of different types of packets transmission inside network such as data , real time audio and video etc. To cope with large number of distinct packets, multicast routers in the network are linked in a tree structure which sends multicast packets to devices con to receive multicast packets. Devices in a multicast routing cannot change their position otherwise they will not be able to communicate. In case of Ad-Hoc wireless network devices dynamically changes their position, this way links are broken and it is not possible to implement multicast tree structure in Ad-Hoc wireless network [2].

2.4 Ad-Hoc Wireless Network's Applications

Because of fewer requirements, easy and quick deployment of Ad-hoc Wireless Network, it is implemented in many areas such as military services, wireless sensor applications, wireless mesh networks and emergency services etc.

2.4.1 Military Services Applications

In military services, Ad-Hoc wireless Networks are utilised as mean of communication due to the nature of the working procedure. For the deployment of Ad-Hoc Network in Military services, two key requirements must be fulfil, the infrastructural network arrangement and the survival of network in any disaster situation [7]. In infrastructural network, stations are connected with a central device (Base stations / Access point), to cover a larger area base stations are install after certain distance. Infrastructure-less network arrangement is not possible during military operations. The Network arrangement must be safe enough to protect network (base stations, nodes and links) from any kind of disaster so that nodes can communication with each other's smoothly [7].

2.4.2 Wireless Mesh Network

Wireless Mesh Network is a form of Ad-Hoc network in which all nodes are connected without having a centralised system i.e. distributed or cloud system and exchanges information. The benefit of such network system is that nodes are connected through multiple links with each others. In case one link goes failure, the alternative link is used to send packets to the destination. Even the failure of a node does not affect the entire network as an alternating path is used to communicate.

2.4.3 Emergency Operation

Ad-Hoc wireless network is also used in emergency services because of its easy, quick and rapid communication nature. In emergency situation infrastructural-less networks is required, because of the mobility of end stations and the nature of the services. In case centralised system exists, when network link goes failure it is not possible to complete any emergency operation. Especially during war the destruction of centralised system can cause serious damage [2].

2.4.4 Wireless Sensor Networks

The size of Wireless Sensor Network is small as compare to other wireless network systems as well as it has the ability of storing data. Wireless sensor devices forms Ad-Hoc wireless network where each device collects information during communication and send these information to one specific node. The function of these nodes is to process all collected information and generate some useful result. These results can predict any upcoming disasters such as floods, rainfall, heavy storms and earth quack etc. apart from, wireless sensor is also used in military operation, due to its small size and it is very difficult to trace because it is tiny device [2].

CHAPTER THREE: ROUTING PROTOCOLS FOR AD-HOC WIRELESS NETWORKS

3.1 Overview

Ad-Hoc Wireless Network is a set of wirelessly linked stations/nodes sharing information and resources with each other's in the network. Since the numbers of stations linked together sending information to each other's required a routing protocol to exchange data between source and destination nodes. The routing protocol is responsible to search for all achievable routes between source and destination nodes and then select the best achievable path from the collected information. The information is gathered from intermediate nodes exchanging information with each other's. There are various routing protocols such as RIP, OSPF and EIGRP operating in wired network collecting routes information's in the network [8]. However they cannot perform routing operation in Ad-hoc wireless network. This is because of the dynamic behaviour of wireless environment where mobile stations/nodes changing their position dynamically [2]. Since a routing protocol is needed which perform routing in ad-hoc wireless network in a distributed manner due to the lack of centralised system in wireless networks for example Access point and Routers [3].

We have explained in previous chapter how data is send and receive in a multi radio hop system PRNET which was supported by the DARPA in 1970s, since the efforts started on development of ad-hoc wireless network protocol. Many Ad-Hoc routing protocols have been developed until now each performs routing operation by taking into account all issues related to Ad-hoc network for example lower bandwidth, more energy consumption and inaccuracy etc [3].

3.2 Major issues In Ad-hoc Wireless Routing Protocols

There are some issues with the Ad-Hoc wireless routing protocols when data is transfer between source and destination nodes. “Some of these issues are mobility, availability of limited resources and availability of low bandwidth etc”. These problems are explained below [2].

3.2.1 Mobility

The dynamic nature of Ad-hoc wireless network constantly changing network topology due to devices regular mobility thus the topology of the network is not similar all the time, therefore Ad-hoc wireless routing protocol is required to quickly updates network information according to the topology changes. Since wired network protocols has the ability to find an alternate route when connection fails but they are slow and cannot work efficiently with the dynamic changes in Ad-hoc wireless network [1].

3.2.2 Availability of low bandwidth

A limited bandwidth is available in Ad-hoc wireless network which is a major issue in fact the routing protocols requires more bandwidth for exchanging updated network information when network changes occurs. Therefore due to exchange of routes information lots of bandwidth is wasted in Ad-hoc network wireless system. In contrast more bandwidth is available in wired network system such as coax and fibre optic cables and route information exchange slightly affects overall performance [2]. However it is not happens in wireless networks due to the requirements of proficient routing protocol, which requires less bandwidth for exchanging route information as well can quickly populate routing table.

3.2.3 Availability of Limited Resources

Limited resources availability is also a major issue in Ad-hoc wireless network, device are continuously changing their position by moving from one location to another. This consumes more battery power and with location changing routing table is populated as well which also consume more battery power. Therefore a routing protocol is required which does not consume more battery power when devices change their position or devices exchanges routes information.

3.3 An ideal Ad-hoc wireless routing protocol's Characteristics

An ideal Ad-hoc wireless routing could be the one, which accomplish the entire requirements and can tackle with all challenges explained in the previous section. These requirements cannot be fulfil using wired protocols as described in the previous section.

Therefore the ideal wireless Ad-hoc routing protocol will have the following Qualities.

1) Routing Protocol must be able to operate in distributed manner rather than centralised. In centralised system protocol consume more bandwidth due to extra overhead with topology information and single point failure is also a big disadvantage. In contrast distributed systems are more reliable and fault tolerant as there is not a single point of failure.

2) Must be able to keep alive the whole network in case of any station failure and isolate the failure system and quickly update routing table with new routes [2].

3) Must operate in proficient way that in case of any changes in the network it must have updated routing table with network and route information [2].

4) There must be a fever number of stations running routing protocol, this will utilise less network resources and will quickly update routing table.

5) The routing protocol must be able to consume minimum resources such as less bandwidth, less battery power when exchanging route information [2].

6) Must be able to provide QOS (quality of service) for real time and sensitive application [2].

3.4 Ad-Hoc On-Demand Distance Vector Routing Protocol

3.6.1 Overview

Ad-hoc on-demand distance vector was first published in 2001 by the Internet Engineering Task Force (IETF) Ad-hoc mobile Wireless routing protocols working group [11]. The working procedure of Ad-hoc on-demand distance vector is based on the principle of Distance Vector Routing Protocol (DVRP) where the station preserve routing table provides network topology information as well path cost towards the destination stations. This particular station keeps up to date routes information, with changes in the network topology all routes are updated accordingly. The cost of the route is measured in number such that the packet will traverse through the number of nodes specified in path cost; in case of destination unreachable path cost is infinity [11].

AODV generates route paths on-demand when path is required to traverse packet. The key difference between AODV and other on-demand Ad hoc wireless routing protocols is to route packet towards the destination source node provide the destination sequence number which is placed in the packet header, each intermediate node towards the destination compare destination sequence number with their own and if they have lesser sequence number than the current packet then they simply update their own information and pass packet to another node. All intermediate nodes do the same operation until packet reaches its destination [2]. Apart from AODV also supports Unicast and Multicast routing.

“In the domain wireless routing the man who originate it and he called as KESHAV it is Hindi pronunciation he expressed precisely Ad-hoc on demand distance vector itself five standard or principle which are that are dispersed Predestined, distinct route, hop-by-hop and self-sufficient [11]”

3.6.2 Route Discovery

When the source station does not have packet destination address it simply send route broadcast request to the neighbour stations. The neighbours will reply with the destination address in case they have otherwise the neighbours will sends broadcast request as well until the request reaches to the destination. The Discovery of route process towards the destination station is shown in the 3.2 where source station S sends a route broadcast request to its neighbour to find route towards destination D. During route broadcast request source node attaches destination sequence number to packet to prevent network from looping as well up to date information are provided [3].

As the intermediate nodes towards the destination receives route request packet, they check the destination sequence number provided against their own. in case they have lesser sequence number than in the current packet , they will update their own routing information with the greater sequence number. The same process is continue until route request reaches the destination or any intermediate node have updated route information towards the destination , in either case the destination route information is send through Unicast reply to the source station [3]. The Unicast reply is send back to the source station as is shown in the 3.3.

3.6.3 Route Maintenance

AODV performs route maintenance in such a way that whenever the source node changing its location is again broadcast route request packet. Route Request packet traverses in the whole network until it reach the destination or any intermediate station reply with updated route information towards the destination [3]. In case of intermediate nodes movement, it's directly connected neighbour detect this movement through messages (hello & dead packets) and informs their upstream neighbours by sending link failure notification message. This Unicast packet traverses the whole network until it reaches the source node therefore the source node will update its routing information with the received packet towards the destination [3].

3.6.4 Ad-hoc on demand distance vector Advantages and Disadvantages

The main advantage of AODV is that it only initiates and establishes route towards the destination when route is needed to send packet to the required destination i.e. on demand routing [2]. Apart from this, to find out latest and up to date route information towards the destination it uses destination sequences number as well this features prevents network from looping [2].

The main disadvantage of AODV is that as the destination sequence number is used to find out the route information towards the destination, therefore the intermediate node may possibly be able to lead to inconsistent information if it have the older destination sequence number and does not have the updated information [2]. Apart from this, Nodes running AODV protocol sending hello packets to each other to ensure that links are up and the participating stations are active which consumes lot of network bandwidth [2].

3.7 Dynamic Source Routing Protocol (DSR)

3.7.1 Overview

The DSR is On-demand routing protocol which means that it only exchanges route information for finding path from source to destination when packets are required to be send to the destination node [2]. It is specially designed for infrastructure-less multi-hop mobile Ad hoc wireless environment [14]. DSR is based on the mechanism of Source Routing protocol which means that routing information is updated only when source node or intermediate node changes their positions. The algorithm is run with poison changing and only currently in use paths are updated [13]. There are two major steps i.e. Route Discovery and Route Maintenance are involved in DSR algorithm which determines and maintains routes [3].

3.7.2 Route Discovery

In the DSR algorithm, Route Discovery is essential process in which every network node finds routes to the destination nodes does not matter whether the destination is directly connected node or through intermediate nodes. When source wants to send packets to the destination node, first it checks for unexpired route towards the destination in its own Route Cache [3]. In case unexpired route exists then it sends packets to the destination using this route otherwise source node simply broadcast Route Request packet as shown in the 3.5.

There are three values exists in Route Request packet i.e. source address, destination address and a unique identifier. When intermediate node receive route request packet and it checks packet for valid route information towards the destination. In case, route request packet does not have valid route information then the intermediate node adds its own address to the packet and forward it to its outgoing (exit) interface. The route request packet traverses the whole network until it reaches the destination. If any of the intermediate nodes have valid route information towards the destination will simply sends a unicast Route Reply packet back to the source node as shown in 3.6. Finally this way the source node will get valid route information to reach the destination node [3].

3.7.3 Route Maintenance

DSR does not perform route maintenance process by sending hello packets to determine whether the neighbour station is alive (active) or not. In fact with the route discovery process route maintenance is also done for the efficient utilization of bandwidth [3]. for route maintenance Route Error and Acknowledgement packets are used, in case of any node goes down all nodes removes routes towards that inactive node as well routes from that inactive node to other nodes from their cache [14].

3.7.4 Dynamic source routing protocol Advantages and Disadvantages

The main advantage of DSR is that prior to routing, exchange of routing information updates and maintenance is not necessary for each intermediate node. it is done only on demand i.e. when routing is required and this way a lot of bandwidth is saved [2].

The main disadvantage of DSR is that prior to routing nodes does not exchanges routing information with each others, this behaviour can possibly lead to inconsistent route information in intermediate nodes routing tables. Therefore as compare to Table driven routing protocols a connection delay is higher in On-demand routing protocols [2].

3.8 Temporally Ordered Routing Algorithm (TORA)

3.8.1 Overview

Temporally Ordered Routing Algorithm is On-demand routing algorithm initiated by the Source node providing multiple loop free routes to the destination node [2]. In TORA, Each node maintains routing table that contains route information only related to directly connected nodes, this way nodes maintain smaller routing table. The advantage of this approach is the localization of control messages such that control message will have smaller overhead in case of intermediate nodes failure [3]. “TORA algorithm contains three basic functions i.e. Route Creation, Route Maintenance and Route Erasure [3]”.

3.8.2 Route Creation

In TORA Route creation is based on Directed Acyclic Graph (DAG), this graph is destination-oriented and route is created with height matrix in graph [2]. Since this process is destination oriented therefore a separate DAG is generated for each individual destination node, The DAG graph having routes from source to destination node [3]. The route creation process is shown in the 3.7.

Consider that when a source node does not have route to send packets to the destination node in the network. So, in this situation the source node broadcast the route request packet to its adjacent neighbour. The adjacent neighbours will re-broadcast this packet to their adjacent neighbours if they do not have destination route information. The route request packet traverses the whole network this way until it reaches to its destination node or to the intermediate node having destination route information [16]. In case the intermediate node have destination route information, it replies back with an updated route request packet contains height from it to the destination node. On the way back neighbours receive this packet will set their own height one greater than the height of the neighbour node where this packet came from. The updated packet will traverse back in the same direction until it reaches the source node and every time nodes will set their height to one greater than the height of the previous neighbours [16].

3.8.3 Route Maintenance

The Route maintenance process in TORA is performed in such manner that, in case of any link failure the effected upstream neighbours sends reverse packet to their upstream neighbours informing them that the link is down. This packet traverses in the reverse direction until it reaches the source node as shown in 3.8 [3]. During link failure update all nodes must be synchronized because the height metric of the DAG is dependent on the link failure logical time [3].

3.8.4 Route Erasure

Route Erasure works whenever a link failure is detected in the network. The adjacent upstream neighbours of the failure node sends a clear packet broadcast message that traverses in the whole network, as a results it erases all invalid routes from every mobile node routing table [3].

3.8.5 TORA Advantages and Disadvantages

TORA main advantage is the logical partitions of the whole network into smaller parts. This logical partition keeps control messages localized for route reconfiguration purpose [2]. As results less overhead is created as compare to other Ad hoc routing protocols in link failure situation.

The main disadvantage of TORA is nodes synchronization time problem due to the DAG graph height metric which is dependent on the link failure logical time [3]. Apart from this the localized route reconfiguration can lead to a less optimal path than before [2].

3.9 Optimized Link State Routing (OLSR)

3.9.1 Overview

OLSR is a Table-driven (proactive) Mobile Ad hoc wireless routing protocol inherits and deploys the efficient link state routing algorithm [32]. The efficiency of OLSR is, in case of link failure the availability of the alternate route. The working procedure of OLSR is based on Multipoint Relaying mechanism where selected nodes called Multipoint Relays (MPRs) in the network sends control packets to each others which minimizes the flooding of control packets in the whole network . The optimization is done by OLSR in two ways; one is by reducing control packets overhead which reduces control packets size and secondly only the nodes in the networks forwards link state information rather than all nodes [2].

3.9.2 Working /Processing of OLSR

As discussed in the previous section that OLSR utilises optimized link state routing mechanism in two ways i.e. first by reducing control packets size and secondly only by the selected nodes forwards link state update information in the whole network. This behaviour of OLSR is shown in 3.9 and 3.10. In the 3.9, all nodes in the network send link update information to their neighbour nodes and these way nodes in the whole network receives link updates information. The working procedure of traditional link state routing protocols is based on this mechanism.

While in the 3.10 it can be seen clearly that only the selected nodes called Multipoint Relays (MPRs) in the network are forwarding link updates information to their neighbour. So, this way optimal information traverses the whole network which reduces network traffic. In the OLSR, There is a method for MPR selection, in which some nodes are selected for forwarding link state update information to the rest of the nodes i.e. to non-MPRs nodes in the whole network. This reduces the network traffic and efficiently utilises network bandwidth which makes OLSR an efficient protocol in terms of bandwidth utilisation.

3.9.3 Benefits and Drawbacks in Optimized link state routing protocol

The main advantage of OLSR is that as a comparison with other table driven-routing protocols it is more suitable protocol because it reduces the overhead of control packets flooding in the whole network by Multipoint Relaying mechanism. Only Multipoint Relays (MPRs) are responsible to forward link update packets in the network [2]. Secondly it also reduces control packets size which consume less bandwidth as well the transfer is in a specific direction [2].

CHAPTER FOUR: Simulation Results & Discussion

4.1 Description of OPNET 14.5 modeller

During my thesis I practiced my simulation on OPNET modeller 14.5 for the comparison of different ad-hoc routing protocols results. These protocols, which I have chosen randomly, are optimized link state, Ad-hoc on demand distance vector and dynamic source routing protocol. The simulation tool (Opnet 14.5 modeller) is a very simple to use. Using Graphical interface users can design network structure easily and can set standard parameters required for Nodes/Stations in the network. The simulation tool also provides errors debugging when simulation runs.

4.2 Simulation Steps

First we will create our individual network model, which reveals the real network substructure of the user. OPNET 14.5 simulator contains large number of existing network models, which can be use for different purposes in any organization. The task of user is to haul the devices, place them on the geographical map and create a link as the requirements of actual scenario.

In 2nd step the task of end user is to set standard parameter values after the creation of network model and the establishment of links among the devices for the successful execution of simulation.

Assigning values to parameters is a condition of actual scenario when the network is deployed, “it means that how the data packets will be created, how much bandwidth will be utilized” and lots of more things will be required for our simulation. It also describes the type of results can be generated, therefore User can tells what type of results will come and how long we will run our simulation to get the final results. All these points will be considered before deployment of any network in the actual globe. These overall results are achieved in 3rd and 4rth steps.

The planned model provides the necessary information from the Graphical image of data that tells us either it will be suitable from business point of view to accomplish the business needs or not. All the above information is considered before making any model in the practical state. These things are truly helpful for companies to insure that network either will give 99.9 percentage reliable results or not.

4.3 Simulation Representation

Representation of MANET protocols depends upon 3 dissimilar criterions, which are data drop, throughput and end-to-end delay.

· Data Drop

Data drop means that how many packets will lose when nodes communicate with each other's or we can say that during the communication how many data packet will be lost at destination node. Mobility of device, humming and interference are the most common factors for data drop.

· Throughput

It means that during transmission of data how much actual bandwidth is obtainable for network. Throughput depends upon many factors such interference etc and during communication 100 % throughput is not achievable.

· Delay

It can be described as how much time will require for the transmissions of data packets from source to destination node. It is caused by lots of factor but some of the important are noise, interference in the carrier, data traffic load and routing table route update etc.

Therefore all the above mentioned factors must be considered before the deployment of the new model. The final result depends on all these factors and based on the generated information form three individual networks scenario we can decide which ad-hoc routing protocol perform well in different situations.

4.4 Network Scenarios

The simulation in this project is based on 3 individual scenarios, which are simulated in OPNET 14.5 modeller. The coming section explains the overall process. On the basis of simulation scenarios results I will find the conclusion that which protocol is the best routing protocol with excellent performance. The three network scenarios are almost similar to each other but only differ in the number of mobile stations (load), they are described in the next section. These mobile stations continuously shift their position during data exchange with each other's. The procedure to create networks scenario is shown in Appendix A.

4.4.1 1st Scenario

1st scenario describes the representation of thirty mobile nodes. These mobile nodes change their position during the interval of time as well as interchange data packets arbitrarily with other nodes.

4.4.2 2nd Scenario

2nd scenario shows the representation of sixty mobile nodes, all nodes change their position during the interval of time as well interchange data packets arbitrarily with other nodes.

4.4.3 3rd Scenario

3rd scenario describes the representation of ninety mobile nodes, all nodes change their position during the interval of time as well interchange the data packets arbitrarily with other nodes.

Note down:

“We have Discussed 3 scenarios situations that's called mobile load, in which nodes are continuously shifting their position with respect to time. Raw data packet are created in every ten sec whose destination IP address continuously interchanging”

“Table 4-1: Showing the parameters of Optimized link sate routing protocol, dynamic source routing and Ad-hoc on demand distance vector routing protocol to find the results

Table 4-1: Setting Parameters in Ad-hoc routing protocols

Table 4-2: Parameters set in Ad-hoc on-demand distance vector routing protocol to run the simulation.

Table 4-2: Ad-hoc on-demand distance vector routing protocol fixed Parameters

Table 4-3: Parameters set in Dynamic source routing protocol

Table 4-3: Dynamic source routing protocol fixed parameters

Table 4-4: Parameters set in Optimized link state source routing protocol

Table 4-4: Optimized link state source routing protocol fixed parameters

4.5 Simulation Analysis & Results

The result of the simulation is based on the three distinct scenarios. The number of loads/nodes changes their position in each scenario. Simulation results will be achieved on the bases of different no of loads that tell how much data dropped, throughput and packets delay occurs in all three scenarios conditions.

4.5.1 1st Scenario (Thirty Mobile Nodes)

4.5.1.1 Data Drop

The graphical representation of data drop tells that how many data packets will lose in 1st scenario, which is based on thirty mobile nodes. By viewing graph in 4-5 it is shown clearly that Ad-hoc on-demand distance vector routing protocol has an insignificant data packet lost as compare to dynamic source and Optimized link state routing protocols when exceeding threshold limit. It means that ADOV requires less time to find an alternative route towards the destination in case primary connection fails.

Although sometime Dynamic source routing protocol has larger amount of data packets drop in (bit/sec) because of mobile nodes performance. It means that DSR takes longer time to update the routing table. The following describes data drop scenario.

4.5.1.2 Throughput

4.6: Illustrates the throughput representation of Ad-hoc on demand distance vector, dynamic source and optimized link state routing protocols. By viewing the graph, the overall throughput of ad-hoc on demand distance vector routing protocol is higher as compare to dynamic source routing protocol and optimized link state routing protocol in thirty mobile nodes scenario. If we see again in the Graph, we conclude that the throughput graph of Optimized link state distance is higher than the throughput graph of dynamic source routing protocol. This means that with less number of loads (nodes) in the network, the Ad-hoc on demand distance routing protocol will perform efficiently. Optimized link state routing protocol is working fine after giving a good performance of AODV but dynamic source routing protocol showing a lesser throughput in the graph as comparative to other protocols “because of its proactive nature of operating”

4.5.1.3 End-to-End Delay

The graphical representation i.e. (End-to-End delay) describes that when we having a thirty mobile nodes in the network, the Optimized link state routing protocol gives insignificant delay in the network as compare to Dynamic source routing protocol and Ad-hoc on demand distance vector routing protocol because of its nature of functioning. The good thing about this protocol is, it only search for path when it is acquire to arrange the packets to be routed. So it takes less time to update the route information table, therefore the end-to-end is minor.

Dynamic source routing protocol showing a highest end-to-end delay in the graph, it means that it takes longer time to reach the destination node as well takes more time in generating & maintaining routing table.

The Ad-hoc on demand routing protocol in the graph shows less end-to-end delay as compare to dynamic source routing protocol because it requires less time to generate & maintain the routing table. Therefore its performance really improves in the network having less end-to-end delay.

4.5.2 2nd Scenario ( Sixty Mobile Nodes )

4.5.2.1 Data Drop

The graphical representation of data dropped showing that how many packets has been dropped in 2nd network scenarios when all three dissimilar Ad-hoc routing protocol functioning together. This graph also tells that how many bits/sec has been dropped in 2nd scenario due to threshold limit exceeding.

In this graph Dynamic source routing protocol showing a higher amount of data dropped bit/sec because of the behaviour of mobile nodes. It means that DSR take much to update the route table as compare to other protocols.

By viewing the graph we can conclude that ad-hoc on-demand distance vector routing has a small amount of data packets drop in the network as compare to Optimized link state routing protocol & dynamic source routing protocol. However one can say we have achieved almost the same results that were achieved in thirty mobile load scenarios.

4.5.2.2 Throughput

4.9: Describe the achievable throughputs of AODV, DSR, and OLSR, when all three dissimilar Ad-hoc routing protocol operating together in 2nd scenario. The graph of Ad-hoc on-demand distance routing protocol showing the highest throughput, means that it works efficiently as compare to Optimized link state distance vector and dynamic source routing protocol.

In the graph Optimized link state distance vector shows greater throughput as compare to dynamic source routing protocol but lower than Ad-hoc on-demand routing protocol, it means that Optimized link state distance vector routing protocol works efficient up to some extent but less than the Ad-hoc on-demand routing protocol.

4.5.2.3 End-to-End-Delay

The graphical Representation of End-to-End delay has achieved by running the simulation of sixty mobiles loads. As the graph shows evident results, means that Optimized link state routing protocol gives good performance as compare to dynamic source routing protocol and ad-hoc on-demand distance vector routing protocol because of its proficient working performance. Also it takes less time to generate & maintain the routing information table but ad-hoc on-demand distance vector routing protocol and dynamic source routing protocols takes longer time to generate and maintain route table.

The good thing of DSR protocol is that it requires very less time to find the substitute route towards the destination in case of primary connection fails. “Therefore its automatic performance really improves the network to have lesser delay as relative to previous routing protocols”

4.5.3 3rd Scenario (Ninety Mobile Nodes)

4.5.3.1 Data drop

The graphical representation of data dropped showing that how many packets has been dropped in 3rd network scenarios when all three dissimilar Ad-hoc routing protocol functioning together. If we look at the graph, it tells that there is no effect on the performance of Optimized link state routing protocol even increasing the no of mobile station/nodes. It still performs efficiently and showing insignificant data dropped packets as compare to dynamic source and ad-hoc on-demand distance vector routing protocols. In the start of the simulation the Ad-hoc on-demand distance routing protocol showing very low percentage of data drop than Dynamic source routing protocol, the reason is it doesn't take much time to update its route table.

After short time the working progress of dynamic source routing protocol and ad-hoc on-demand distance vector routing protocols having similar speed.

4.5.3.2 Throughput

4-12 “Describe the achievable throughputs of AODV, DSR, and OLSR, when all three dissimilar Ad-hoc routing protocol operating together in 3rd scenario (ninety mobile nodes). Graphical results describes that the overall throughput of Ad-hoc on demand distance vector routing protocol is higher than other two protocols. And also it verify that when increasing the no of mobile load in the 3rd scenario network, work load will also be increased so in this condition Ad-hoc on demand distance vector still operate better than OLSR and DSR. The graph of the Optimized link state routing protocol is decreasing when we increase the mobile load from sixty nodes to ninety nodes. “In the mean time dynamic source routing protocol show less recital as compare to ADOV & OLSR because of its proactive performance”.

4.5.3.3 End-to-End Delay

The graphical representation of End-to-End delay shows the evident results, it means that Optimized link state routing protocol gives good performance as comparison to dynamic source routing protocol and ad-hoc on-demand distance vector routing protocol because of its proficient working performance. The results shows that Optimized link state routing protocol takes less time to generate & maintain the routing information table but ad-hoc on-demand distance vector routing protocol and dynamic source routing protocols takes longer time to generate and maintain the routing table. The most important thing of OLSR protocol is that it requires very less time for finding the substitute route to approach the destination when routing is needed. Therefore its automatic performance really improves the network to have less delay as relative to other routing protocols. In the start Ad-hoc on-demand distance routing protocol was giving better results, however after short time the working progress of this protocol is began to start decreasing as well the dynamic source routing protocol because both takes longer time in generating & maintaining routing table, therefore data packets faces more delay.

4.6 Summary

The final conclusion of this chapter described the simulation results which are based on 3 various dissimilar scenarios. As we know that all above 3 scenarios has dissimilar number of mobile load/station and each node constantly shifting their position due to time. In addition they have various unlike raw packets created inside the system that's the destination addresses are changing with respect to time. “The output/results come after the execution of Opnet 14.5 simulator with in twenty minutes. Each time we ran dissimilar routing protocols (dynamic source routing protocol, Optimised link state routing protocol and ad-hoc on-demand distance vector routing protocol) that's tells which protocol gives better results and performance based on data dropped, delay & throughput”.

CHAPTER FIVE: CONCLUSION & SUGGESTION FOR FURTURE WORK

5.1 CONCLUSION

This thesis report tells that mobility play a very important role in the effectiveness of Ad-hoc routing protocol network when mobile nodes constantly changing their position with respect to time, it means that at each instance it renews and updates the route information table. This thesis report also notifies the performance of different protocols working in a proficient manner and shows a huge impact on the effectiveness of ad-hoc network.

Eventually in this thesis report I found that Optimized link state routing protocol gives extra consistency and trustworthiness as compare to other ad-hoc routing protocols due to its insignificant data dropped shown in three distinct network scenarios.

Although Ad-hoc On-demand distance vector protocol also shows extra reliability as compare to Optimized link state routing protocol and Dynamic source routing protocol because it takes less time to generate and maintain routing information table.

On the bass of the overall throughput of ad-hoc network I concluded that Ad-hoc On-demand distance vector protocol gives maximum amount of throughput and thus analyse that it is extra proficient protocol as compare to other protocols such as Optimized link state routing protocol and Dynamic source routing protocols.

In the network, Optimized link state routing protocol also gives more throughput when we compare it with Dynamic source routing protocol because DSR takes more time to generate and maintain the route towards the destination. The performance of Dynamic source routing protocol is decreases by increasing the mobile station and shifting the position dramatically.

End-to-Delay Graphs of all three scenarios conclude and analyse that optimised link state routing protocol (OLSR) works efficient in manner and gives better results as compare to Dynamic source routing protocol & Ad-hoc On-demand distance vector protocol. Optimised link state routing protocol is best protocol because of its Reactive manner of acting and it create and maintain the route table in short time as compare to other protocols because each time it save the alternative route to the destination in the routing table.

Eventually the overall result of this thesis shows that Optimized link state routing protocol is best protocol because it gives higher throughput, insignificant delay and less data dropped in the network and extra consistency and trustworthiness as compare to other ad-hoc routing protocols.

5.2 SUGGESTION FOR FUTURE WORKS

In Opnet modeller 14.5 there is a limited availability of Ad-hoc routing protocols that truly put restrictions on this thesis. Although we can do further study and research on the behaviour of Ad-hoc network if there is availability of further Ad-hoc routing protocols in Opnet modeller 14.5 and “the performance of these Ad-hoc routing protocol can be investigated on the bases of data dropped, throughput and delay ”.

Appendix A: Network Model designing in OPNET 14.5. Modeller

Step I

Step II

Step III

Step IV

Step V

Step VI

Step VII

Appendix B: Creation of Raw packets in OPNET 14.5 Modeller

Abbreviations Dictionary

“AODV Ad-hoc On-Demand Distance Vector Routing protocol

BS Base Stations

CSMA Carrier Sense Multiple Access

DSR Dynamic Source routing protocol

DARPA Defence Advanced Research Project Agency

DSDV Destination Source distance Vector Routing

DES Discrete Event Simulator

EIGRP Enhanced Interior Gateway Routing Protocol

FTP File Transfer Protocol

HTTP Hyper Text Transfer Protocol

IETF Internet Engineering Task Force

IGRP Interior Gateway Routing Protocol

LSA Link State Algorithms MANET

OSPF Open Shortest Path First

OLSR Optimized Link State routing protocol

PRNET Packet Radio Network

QRY Query Packet

RIP Routing Information Protocol

RREQ Route Request

RREP Route Reply

RERR Route Error

SURAN Survivable Radio Networks

SOPRANO Self-Organizing Packet Radio Ad hoc Networks with Overlay

TTL Time to Live

TORA Temporally Ordered Routing Algorithm Protocol

UPD Update Packet”

References

[2] C. Siva Ram Murthy and B. S. Manoj, “Ad hoc Wireless Networks: Architectures and Protocols,” by Prentice Hall PTR in 2004, pp. 191-223, 299-359.

[3] C. -k. Toh, “Ad hoc Mobile Wireless Networks: Protocols and Systems,” by Prentice Hall PTR in 2002, pp. 13-25, 27-37, 57-77.

[4] J. M. McQuillan and D. C. Walden, “The ARPA Network Design Decisions,” in Computer Networks, vol. 1, August 1977.

[5] F. Ramirez-Mireles and R. A. Scholtz, “Multiple-Access Performance Limits with Time-Hopping and Pulse Position Moudulation,” Proceedings of IEEE MILCOM 1998, vol. 2, October 1998.

[6] M. Z. Win and R. A. Scholtz, “Ultra-Wide Bandwidth Time-Hopping Spread- Spectrum Impulse Radio for Wireless Multiple-Access communications,” IEEE Transactions on Communications, vol. 48, April 2000.

[7] ARC Communication Research Network (ACORN) - Ad Hoc Networks at http://www.acorn.net.au/report/adhocnetworks/adhocnetworks.cfm

[8] Todd Lammle, “CCNA Cisco Certified Network Associate Study Guide,” by Sybex Publishers, an imprint of Wiley, edition 6, pp 330, 2007.

[9] Shih-Lin and Yu-Chee Tseg, “Wireless Ad Hoc Networking: Personal-Area, Local-Area and the Sensory-Area Network,” Auerbach Publications, 2007, ISBN: 0- 8493-9254-3, pp. 535-571

[10] Masayuki Tauchi, Tetsuo Ideguchi and Takashi Okuda, “Ad-Hoc Routing Protocol Avoiding Route Breaks Based on AODV,” at proceedings of 38th Hawaii International Conference on System Sciences, 2005

[11] Rainer Baumann, “Ad Hoc On-demand Distance Vector Routing Protocol (AODV)” Presentation at ETH Zurich, April 2002.

[12] Jin-Man Kim, Jong-Wook Jang, “AODV based Energy Efficient Routing Protocol for Maximum Lifetime in MANET,” at Dong-Eui University, Department of Computer Engineering, 995 Eomgwangno, Busanjin-gu, Busan, Korea.

[13] David B. Johnson and David A. Maltz, “Dynamic Source Routing in Ad Hoc Wireless Networks,” at Carnegie Mellon University, Computer Science Department, 5000 forbes Avenue Pittsburgh, PA 15213-3891.

[12] David B. Johnson, David A. Maltz and Josh Broch, “DSR: The Dynamic Source Routing Protocol for Multihop Wireless Ad Hoc Networks,” at Carnegie Mellon University, Computer Science Department, Pittsburgh, PA 15213-3891

[13] Miguel A. Ortuno Perez, Vicente Matellan Olivera and Luis Rodera Merino, “Abbreviated Dynamic Source Routing: Source Routing with Non-Unique Network Identifiers,” at University of Rey Juan Carlos, Mostoles, Madrid, Spain.

[14] David A. Mailtz, “The Dynamic Source Routing Protocol,” at http://www.cs.cmu.edu/~dmaltz/dsr.html, updated on 23/07/2003.

[15] Ana Cavalli, Cyril Grepet, Stephane Maag and Vincent Tortajada, “A Validation Model for the DSR Protocol,” at Institute of National Telecommunications, 9 rue Charles Fourier F-91011 Evry Cedex, France.

[16] Zulfiqar Ali, “Performance Comparison of Ad Hoc Routing Protocols,” at Brunel University, School of Engineering & Design Electronics & Computer Engineering, February 2007.

[17] Asad Amir Pirzada, Chris McDonald, “Trusted Route Discovery with Temporally Ordered Routing Algorithm Protocol,” at the University of Western Australlia, School of Computer Science & Software Engineering, Crawley, W. A. 6009, Australlia.

[18] Tomoyuki Ohto, Munehiko Fujimoto, Shinji Inoue and Yoshiaki Kakuda, “Hi- Tora: A Hierarchical Routing Protocol in Ad Hoc Networks,” at Hiroshima City University, Department of Computer Engineering, Hiroshima 731-3194, Japan.

[20] Path detection in Temporally Ordered Routing Algorithm [21] Path Preservation in Temporally Ordered Routing Algorithm

[22] Fan Hong, Liang Hong and Cai Fu, “Secure OLSR,” at Huazhong University of Science and Technology, College of Computer, Wuhan 430074, China.

[23] Jean-Marie Orset and Ana Cavalli, “A Secu

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