The Proactive Routing Protocols in Mobile Ad Hoc Networks

The proactive routing protocols:

Generally, in the table driven routing protocols or the proactive routing protocols a dynamic and appropriate entry for the routing towards the target is available across the routing table of various nodes in the network. The static route is gripped by these particular routing protocols if it is not required and therefore these protocols are capable of maintaining the quality of control that is needed. Two routing protocols are considered under the proactive routing protocol category and they are the OLSR “Optimized Link State Routing Protocol” and DSDV “Destination Sequence Distance Vector routing protocol”. The brief explanation of these two routing protocols is as follows:

DSDV routing Protocol:

Destination Sequence Distance Vector routing protocol implements few common techniques and the one among the techniques is Bellman-ford and this is regarded as the significant technique for DSDV.The specific information related to the routing is represented by maintaining a particular sequence for all the routing entries in the routing table.

A separate routing table is maintained by every node and that routing table keeps up the common information related to the nodes like the hops count that has been transferred across that particular targeted node, the information of destination series numbers and even the alternate hop’s information is also maintained by the routing table.The updates of all the nodes are generated across the routing tables and the consistency of the routing tables is managed at a specific time in the DSDV routing protocol and then the routing procedure is continued.

                       DSDV routing protocol make use of all the updates of the node that are available in the routing table and these updates are generated by using the network configuration updates that are known during the complete procedure. The route stability across the network is maintained by the DSDV routing protocol by making used of the possible updates.

The estimation of route stability and the related reactions will completely decides the performance of the routing protocoland if a link failure or a route failure in the route is identified across this process,DSDV routing protocol is used to allot the unique sequence number and infinity variable to the routes. During this process an update is triggered as soon as the infinity metrics are discovered by the node that is towards the route.

In such situations in order to maintain the stability of the route the failed route will be replaced with a new route. Two conditions are generally considered during the process of triggering the updates of the table and they are given below:

  1. During this complete process when the greater sequence number is used for receiving a data packet then instantaneously the information that is already existed is replaced.
  2. The updating of the routing table is done depending on the same sequence number 

The optimized link state routing protocol (OLSR):

The Optimized Link State Routing protocol is simple referred as OLSR routing protocol and this comes under the proactive routing protocol category. In this routing protocol the various kinds of routes that are required for the routing process are accessible every time. The OLSR routing protocol utilizes the Multi Point Relays MPR for reducing the transparency across the network, the occurrence of topological changes in a network will lead to this transparency.

The situation of flooding which is caused by the continuous broadcast of duplicate messages is caused in the network if in case there are number of topological changes occurs in the network. When a same message is transmitted for number of types across the same region then that is called transmission of duplicate messages or it is also referred as flooding. This flooding situation caused by this duplicate forwarding of messages can be decreased using the MPRs.

The status of the changes caused in the network topology can be can be identified by knowing the information related to the link state of the node and by broadcasting that information across the network using the hello messages and also by using the topology control and OLSR routing protocol. In general, in order to know about the changes that occurred due to the mobility behavior possessed by the nodes those are across the topology of the network, by transmitting the hello messages at the particular node level only and also by transmitting the topological changes messages across the entire network.

The messages of topology changes are forwarded across the entire network in a periodic manner when a change in the topology of the network is identified across the network and this is done by making use of the MPRs. Therefore the situation of flooding caused by the broadcasting of duplicate messages can also be decreased by the use of MPRs.

The advanced and enhanced version of link state algorithm is regarded as the OLSR routing protocol in this protocol also for the similar nodes the information of the link state will be same. The chances for reducing the control packets size will be more with the proper implementation of the OLSR routing protocol, and along with this the maintenance of the information related to the subset of links relatively than the complete information of the link of the specific network.

The information of the topology control can be optimized using the multi-point relays. The OLSR routing protocol is considered as one of the best routing protocol among all the other routing protocols established for the MANETs.The optimization can be achieved by subjecting the hello messages which is permitted by all the nodes for identifying the information related to the nodes adjacent and then by continuing the process for identifying the hop count directed towards that particular node.

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