What are Routing Protocols? Defines its Types


Routing is how data packets move from source to destination in a computer network. The word’ routing’ comes from the word ‘route,’ also called way. So, Routing is a way to find a path from source to destination. A device called a Router is used to find this path. The router is a device through which we perform the routing task. The Routing protocols are a set of rules with the help of which Routers communicate, share information, and store it in their routing table.

Types of Routing Protocols

There are three types of Routing Protocols.

  1. Static Routing
  2. Default Routing
  3. Dynamic Routing

Static Routing

It is a procedure in which a network administrator or engineer manually configures routes or every router in a network. He/She enters every Router information or routes manually in a Router. Static routing is best for small organizations because it has no extra costs such as bandwidth. There is no overhead of static routes. Moreover, it has followed the said path.

Router(config)# Destination-Network subnet-mask  Next-hop-Address

If the destination network with its subnet mask is and the next hop address is, then we can write the static route as,


Default routing

The default route is the route of the last resort. If our network doesn’t solve a query, it is sent to a network that connects to the Internet or outside of a network. It can be sent to a network configured as a last-resort gateway. If a computer doesn’t find its information in a network, it is sent to a default gateway. This gateway is called the gateway of the last-resort network.

The default route is written as,

Router(config)# destination-network subnet-mask next-hop-address

for example


Default Routing

Dynamic Routing

It is also called automatic routing. The Router finds its best path by itself using a dynamic routing protocol, which is also called routing by routing protocol. This process is automatic, but the network admin must run or configure it. These protocols share their routing information. The router finds the best path to the destination network through the information stored in its routing table. It distributes this information to other routers configured with similar routing protocols.

      Dynamic routing is divided into two main categories: IGP and EGP. IGP stands for interior gateway routing protocol, while EGP stands for exterior gateway routing protocol.

      IGP is used within a single autonomous system while EGP connects different autonomous systems. An autonomous system is an entity under the control of a single administrator.

IGP is subdivided into distance-vector, links-state, and hybrid routing.

Distance Vector Routing Protocols

How many hops are away from the destination me, and from which side? That’s why it is called a distance vector. It uses hop count as a metric. It sends its entire routing table in its update while the updates are periodic (30 sec). Examples of Distance vector protocols are RIP v1, RIP v2, and IGRP.

Distance vector routing protocols

The Router will prefer Path B in the above path due to its lower hop counts.

Link-state Routing Protocol

It performs the routing task by accessing the link (interface) status and connection type. The status indicates whether the link is up or down, and the connection type indicates whether it is ethernet, fast ethernet, or serial interface. Based on these factors, it decides which link is faster! It will prefer the path with greater bandwidth.

Link-state routing protocols

It will prefer Path 1 in the above diagram due to its higher bandwidth. Link-state uses the Dijkstra algorithm to find the best path to the destination. At the last, it will load the best path in its routing table.

Hybrid  Routing Protocols

Hybrid Routing protocols combine the best features of distance vector and link-state routing. They use hop count and bandwidth to find the best path to their destination. EIGRP is a hybrid protocol.

There is only one EGP protocol, the Border Gateway Protocol, or BGP. We are using BGP to connect different Autonomous systems.

Difference between static and dynamic routing protocol

There are many differences between static and dynamic routing, but some differences are given below:

  1. Routing update

We do manual changes in the network while there is an automatic update if any change occurs.

  1. Network Infrastructure

Static is best for small networks, while Dynamic routing protocols is best for medium to large organizations.

  1. Flexible

We configured a static path from source to destination, if that path fails, then the route doesn’t find the alternative path by itself, while the Router finds the best alternative path by itself if the primary path fails in the dynamic case.

  1. Admin overhead

A network admin is responsible for static routing. He will do everything manually while in Dynamic routing, there is low overhead on the network admin.

  • Control

Static routing provides more control over a network while we have less control over a network in the dynamic.

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