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The route discovery process

The total number of the routing protocols which are present in the MANETs should follow the route discovery process. The DSR will make an investigation regarding the current route towards the destination starting from the source that is required to forward few packets. In the entire process if it is identified and considered as the non expired route then the packets are been broadcasted towards the target by making use of the similar route as well as the communication process. And if the source is not able to identify any type of the current route then the DSR will raise the request towards the nodes for the purpose of the valid route .

Generally the route request is been transmitted as the packet which is called as the RREQ-route request packet as well as this particular packet is been transmitted towards the entire nodes which are present within the network. The major attributes such as the source as well as the destination IP address are been maintained by the RREQ through the single request id that is been situated through the sender.

In the entire process if at all the node identifies the fake route request then it will be immediately happened to be unnecessary and it will even verify that they belongs to the desired destination nodes or not. The unicast operation which is difficult is been carried out in order to forward the RREP messages towards the source rather than transmitting the message in order to finish the total network. Within the process of transmitting as well as the performing the unicast operation each and every node is capable of updating the route along with its route cache.

The dynamic source routing protocol (DSR)

The major function of the dynamic source routing is entirely based upon the terminology of source routing. The route discovery process which is been carried out within this particular routing protocol is entirely different from the current routing protocols. The dynamic information is been utilized in order to decrease the broadcast messages as well as the advertisements of the periodic routing. The routes determination is been carried out in a dynamic way depending upon the cache information which is accessible or else the routing information which is been obtained by making use of the requests related to the sources in the form of the broadcasts towards the total networks.

The initial step within the process of routing is that the sender will situate the entire information about the total nodes which are to be navigated through the packets. And this specific information is been identified upon the packet header before the process of actual routing is been done. One of the significant benefit of this routing is the information related to the routing preserved through the intermediate nodes is been excluded as well as the essential information for the process is been sustained within the packet header. By making use of this routing protocol the advertisements related to the periodic route could be totally excluded and the overhead control will be totally decreased. The general function of the DSR routing protocol is again divided into two different steps such as the Route discovery as well as the Route maintenance which are been explained in detail as follows.

The reactive routing protocols

The reactive or else the on demand routing protocols are some what different and are varied from the table drive routing protocols. It is already been proved that they will not sustain any type of the static routing information as well as they are entirely dynamic in nature relevant to that of the routing information. Depending on the specific demands the route towards the target is been constructed. The first and the major task of this routing protocol is they will verify the current routing information and if the information is similar then it will be utilized and if it is not same then it will ask for some requests towards the networks in order to implement the routes towards the destination.

The routing information which is been reserved with this particular protocols is not static and in the ongoing process if at all the route is identified to be inactive for some extent, then it will expire then the new routes are been implemented based on the requirements and then these specific protocols are been considered as the on-demand routing protocols. This protocols are if soft state which is been sustained all over the routing tables. The reactive routing protocols are having two different types of the routing protocols such as the DSR-dynamic source routing as well as the AODV- Ad Hoc on demand vector which are been explained in detail as follows.

The optimized link state routing protocol (OLSR)

The OLSR is referred to as the optimized link state routing protocol which belongs to the proactive routing protocol in which the different types of the routes required for the purpose of the routing are always offered and available. In order to decrease the transparency which is happened because of the topological changes towards the network this protocol will make use of the MPR- multi points relays.

In the continuous process if more number of the topological changes takes within the networks then there is a possibility that the similar types of the message is been transmitted towards the similar area for several times which will leads to the typical situation called flooding. The multi point relays could be utilized for the purpose of reducing the flooding which is been happened because of the fake transmission. By means of the hello messages and by making use of the OLSR routing protocol as well as the Topology control, the information about the link status that belongs to the node could be identified and broadcasted towards the entire network in order to know the current status of the topology changes within the network.

Generally the hello messages are been transmitted only at the specific node level, whereas, the messages of the Topology changes are been transmitted all over the network in order to identify the changes that will take place because of the process of the mobility of the nodes which are towards the topology that is been built. The MPR- multipoint relays are been utilized for the purpose of forwarding the Topology changes messages and then this particular messages are been transmitted as well as forward in a periodic manner towards the network every time when there is the topology change that is generated in the network.

By making use of the MPR the information exchange which is towards the network could be easily decreased and it is even capable of decreasing the broadcast flooding. The OLSR is considered to be one of the developed and advanced version of the link state algorithm by which the link state information is similar to that of the equivalent nodes. By establishing the OLSR routing protocol in an appropriate manner there are more chances to decrease the size of the control packets as well as the information that belongs to the subset of the links is been sustained rather than the entire link information of the particular network.

By making use of the MPR the optimization aspect can be easily attained by which the control information is been optimized. Among all the existing routing protocols of the MANETs this particular protocol can be considered as one of the best protocol. In order to obtain the optimality each and every node will permit and subject the hello message in order to recognize the information about the adjacent nodes and then the by carrying this process the required numbers of the hop node is been recognized. Basically the Topology changes size is high and it is forwarded towards the networks and to complete this there is a necessity of having the required knowledge on the entire parts of the message in order to generate topology changes towards the adjacent nodes.

The destination sequence distance vector routing (DSDV)

The Bellman-ford is considered as one of the general technique which is been established for the purpose of the destination sequence distance vector routing. The specific order is been sustained for the purpose of each routing entry that belongs to the routing table in order to indicate the particular information regarding the routing. Each and every node will include the different types of the routing tables which will maintain the general information such as the total number of the hops that are to be transferred towards the target node .

It will even maintain the information about the alternate hop as well as the destination series numbers. The table consistency which is towards the DSDV is been controlled in particular time as well as it will generate the updates that are obtained from each and every node in which the routing process is been carried out.

In the entire process if at all the configuration updates related to the networks are been utilized then the nodes will generate the updates and then the DSV will utilized these specific updates in order to uphold the route stability which is diagonally towards the network. The performance of different types of the protocols is entirely based on the reactions of the routing stability and in this process if the link or else the route breakdown is been detected towards the route then the infinity variable is been allotted for the routes and then the unique sequence number is been allotted by making use of the routing protocol of the DSDV.

Within the ongoing process if at all the node which is towards the route identifies the infinity metrics then it will immediately generate the updates. Then after the new route is been restored by means of the non-working route in order to sustain the routing stability of the network. Depending on the total information which is been received the updates of the routing table are been carried out that are starting from the new infinity metrics and then after they are compared by the current information which is already present in the process. Basically the updates related to the tables are been performed by considering the two different conditions such as above:

• In the entire process if at all the packet is been received by using the greater sequence number then immediately it will be replaced by the current information.
• Based on the similar sequence numbers the routing table is been updated.

The proactive routing protocols

Basically the proactive or else the table driven protocols are having the spontaneous and convenient routing entry to the target which is diagonally towards the routing table of different types of the nodes. Even though there is no necessity these specific protocols will always hold the static route towards the destination and then the sufficient quantity of the control is been maintained by these protocols. There are two different types of the protocols such as the DSDV-destination sequence distance vector as well as the OLSR- optimized link state routing which belongs to the table driven protocols.

• The destination sequence distance vector routing (DSDV)
• The optimized link state routing protocol (OLSR)

The routing protocols of MANET

Now a day’s the mobile technologies have gained more importance and for this reason the different types of the applications related to the mobile computing are been utilized all over the world. Generally there are more possibilities for the process of developing the current technologies which are having more demand. The mobile Ad Hoc networks are considered as the best one among the existing mobile technologies because it is having one of the major benefit that there is no necessity architecture and this specific networks are capable of functioning themselves which are referred to as the autonomous systems.

The typical MANET major function is to manage the routers as well as the wireless links among them. The routers are made up of the mobility nature and for this reason they are capable of moving from one specific location to the other location diagonally towards the virtual graph which is been created through the routers as well as the wireless links.

Because of the presence of the individual nature and the few infrastructure operations the MANET will be able to attached or connected to any kind of the internet as well as it could even be functioned and controlled in a separate manner . It is already been proved that the mobility is considered as the general nature of the MANET and then there are more possibilities of happening of the issues for the route or the link stability, and then there is a necessity of the appropriate routing protocols in order to assure the routing stability towards the MANETS. In general there are two different types of the routing protocols such as the proactive routing protocols( table driven) as well as the reactive routing protocols(on demand).

Improving the security for the wireless LAN network is the key study area in this paper and to achieve this two scenarios are created using the OPNET modeler simulation tool. First scenario deals with the default wireless LAN configuration and the second scenario deals with the secure wireless LAN configuration. A MANET is simulated for these purposed and 10 wireless LAN mobile nodes are used and a single wireless LAN server is created to support these nodes.

OLSR routing protocol is used for routing purpose and three applications are created in these scenarios to generate the traffic and they are video, voice and FTP and they generate the CBR and TCP traffic respectively. When the two scenarios are created they are simulated and the results are analyzed and from the analysis few observations are derived and they are as given below 

When all the scenarios are compared against the performance metrics used, it is observed the performance of the secure wireless LAN is high when compared to the normal wireless LAN configuration. Key aspects like FTP, Voice, Video and Wireless LAN metrics are compared against the scenarios and across all the comparison process the secure wireless LAN parameters has imposed an optimal conditions on the network in terms of routing, traffic sent, traffic received, jitter, load and delay.

From this indication it is understood that if the parameters of the wireless LAN are changes to ensure the safety across the network then the overall performance of the network is improved a lot across any application used in the network. Secure wireless LAN settings has ensured a optimal packet delivery ratio, reduced the congestion on the network by minimizing the traffic sent and received across the nodes and thus it is proved that wireless LAN performance is optimized with the required security considerations.