Question

Explaine Dynamic Routing with practical examples

Answer 1

Dynamic routing is also known as adaptive routing which change routing table according to the change in topology. Dynamic routing uses complex routing algorithms and it does not provide high security like static routing. When the network change(topology) occurs, it sends the message to router to ensure that changes then the routes are recalculated for sending updated routing information.

Dynamic routing uses a dynamic routing protocol to automatically select the best route to put into the routing table. So instead of manually entering static routes in the routing table, dynamic routing automatically receives routing updates, and dynamically decides which routes are best to go into the routing table. Its this intelligent and hands-off approach that makes dynamic routing so useful.

Dynamic routing protocols vary in many ways and this is reflected in the various administrative distances assigned to routes learned from dynamic routing. These variations take into account differences in reliability, speed of convergence, and other similar factors.

Consider the network diagram shown below.

The administrative overhead that would be needed to make communication between all these devices would be considerable. All the static routes would have to be configured.

Wouldn’t it be much easier, for the network administrator to just “Teach” the routers how to get from one point to another? The solution to this problem would be dynamic routing protocols.

Dynamic routing protocols are a solution that is used in large networks so as to reduce the complexity in configuration that would be occasioned by having to configure static routes. In most networks you will see a mix of both dynamic and static routes.

Dynamic routing protocols can be classified in several ways.

• Interior and exterior gateway routing protocols,

• Distance vector, path vector and link state routing protocols,

• Classful and classless.

Advantages and disadvantages

Advantages

• Exchange of routing information when there is a topology change is dynamic.

• Less administrative overhead as compared to static routes which have to be manually configured

• Less error prone than static routing which.

• Scalability, since there is less administrative overhead than static routes.

Disadvantages

• Require more expertise by the administrator, they are not as simple to configure as static routes.

• They use more of the routers resources; such as CPU and RAM.