Dynamic Routing And Its Type.

Definition-What is DYNAMIC ROUTING?

We already learned what is static routing?, in our previous question and Answer session. So our this session mainly focuses on Dynamic Routing. So lets get Started.

 As the name suggest dynamic means, capable of action and or do changes on its own. So In dynamic routing, protocols are configured on the router which enables the router to select the best path to the remote network according to the real-time logical network layout change. The protocol that is configured does all the work on its own like maintaining and updating routing table, whereas we all know in static routing all these tasks need to be manually done by network admin.

READ ALSO: Static Routing In detail.

But there is one main condition for dynamic routing to work and that is, routers in communication must use the same dynamic routing protocols. For example if one router is configured with RIPv2 routing protocol then the second router must also be configured with RIPv2 routing protocol.

NOTE: you can also configure two routers with different routing protocols and can still communicate,but in this case we will have to use redistribution, which we will talk about later

Explanation In Details- DYNAMIC ROUTING.

Popular Dynamic Routing Protocols:-

1. RIP- Routing Information protocol.
2. EIGRP- Enhanced Internal Gateway routing Protocol.
3. OSPF- Open shortest Path first routing protocol.
4. BGP- Border gateway protocol.

Important Terms In DYNAMIC ROUTING

ROUTING:-  

The term routing refers to taking packets from one device and sending it through the network to another device on a different Network. (Note here device means Router).

READ ALSO: Static Routing In detail.

ROUTING TABLE:-  

In computer networking, there is one more term for routing table ie routing information base(RIB). So it is a database stored in a router that lists the routes to the network destination along with the metrics(distance in this case) associated. The main function of this database table is to store and maintain the best path to reach the destination remote networks, which the used by the router to send the data traffic or packets.

COST:- 

This the most important calculation in selecting the best path to reach the destination network if there are many paths available to reach the destination. Cost is calculated on various factors and the method differs for different protocols. 

The less cost route will be selected as the best path. We will talk more about this, when I will explain all the dynamic protocols in details in our next session.

BEST PATH:-

This is best route to reach the destination network, which is selected by the dynamic protocol configured on the router on the basis of cost.

READ ALSO: Static Routing In detail.

ADMINISTRATIVE DISTANCE(AD):-

The administrative distance is used for rating the trustworthiness of the routing protocol and its information received from the neighbor router.

AD value ranges from (0-255) in integers. In which 0 is the  most trusted one while the 255 is the least trusted.

Also if there are more then one routing protocols configured on a router, then the protocol  having information with the least AD will be given priority and placed in the routing table.

Table showing administrative distance of most popular Dynamic Routing Protocol is below.

  

Name Of Protocol	AD
RIP v1	120
RIP v2	120
EIGRP	90
External EIGRP	170
OSPF	110
External BGP	20
Internal BGP	200