What is dynamic routing?

Dynamic routing is a networking technique that provides optimal data routing. Unlike static routing, dynamic routing enables routers to select paths according to real-time logical network layout changes.

Dynamic routing uses multiple algorithms and protocols. The most popular are Routing Information Protocol (RIP) and Open Shortest Path First (OSPF).

Dynamic routing protocols allow routers to share information about the network with other routers to allow them to select the best path to reach a destination.

Dynamic Routing protocols

RIP

Routing Information Protocol version 2 (RIPv2) is an old routing protocol. RIPv2 suffers from scalability issues due to a relatively low maximum hop count of 15 routing devices. Compared to more modern dynamic routing protocols, RIPv2’s methods for selecting optimal routes and the substantial convergence time it takes to recalculate paths renders it nearly obsolete.

OSPF

OSPF is the dynamic routing protocol used in large to very large IP networks. The protocol uses a link-state database and link-state advertisements to map the network topology. This topological map is used with the link-state algorithm to determine the best route available. The algorithm used by OSPF to determine best routes relies on the link-state database and allows OSPF to update its routes faster than RIP when a network change is encountered. OSPF uses areas to segment the network, which helps it decrease the general size of the link-state database and consequently speeds up network convergence when changes in the network are experienced.

Advantages of Dynamic Routing

• Allows the exchange of routing information whenever the network experiences a change in topology.
• Since the routes do not have to be configured manually, there is less administrative overhead.
• Less error-prone than static routing.
• Allows scalability since there is less administrative overhead involved.