Question

Research the dynamic routing protocols

1. How it works /fundamentals

2. Why we use it /pros and cons

3. What role does it play for internet service providers- why isp providers only use it

Answer 1

Routing protocols are used to enable the routers exchange routing information, they allow routers to learn about remotely connected networks dynamically. This information is then added to their routing tables as a basis for forwarding packets.

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.

Routing protocols are comprised of processes, messages and algorithms that are used by routers to learn about remotely connected networks from routers that have been configured with the same routing protocols, the routes that have been learnt are added to the routing table and used as a basis for forwarding packets.

• Routing protocols function by:

• Discovering remote networks

• Maintaining current routing information

• Path determination

The routing protocol is made up of these components.

1. Data structures – this is information about remote networks. It is usually stored in the RAM and may be comprised of tables such as neighbor tables and topology tables.

2. Algorithm – this is the sequential list of steps that the routing takes when determining the best path to a particular network.

3. Routing protocol messages – these are messages that are used to maintain updated routing information. Examples include; hello messages, update messages among others.

The way routing protocols operate may differ depending on the routing protocol, however, there are certain characteristics inherent in every routing protocol.

• Exchange of information on interfaces to discover neighboring routers

• Exchange of routes that have been advertised

• Running of the algorithm so as to determine the best path

• Adding of best paths to the routing table

• Detection of topology changes and making the necessary changes

These are the general steps routers will take. However, the processes differ with each routing protocol and will be discussed at a later stage.

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.