IP Route plus Routing Protocol

[John Rener]

Hello Cisco Gurus,

Can you please help me understand why I need an IP route as well as a Routing protocol? Let's say I only need one, but is it better to have both?

Thanks in advance!

[balaji.bandi]

Depends on your requirement, with basic route you can use static route.

If you have dynamic routing requirement in the network, you need routing protocol configuration required.

[Georg Pauwen]

Hello,

in addition to the other posts, it all depends on the size of your network. If you have only one router, a static default route is usually sufficient, and also more economic, since routing protocols use CPU and memory.

Below is a good article and when and where to use both:

Where to use static and where to use dynamic routing?

https://www.grandmetric.com/2017/08/25/where-to-use-static-and-where-to-use-dynamic-routing/

[paul driver]

Hello

You'll probably require both in a scenario lets say --
when your running dynamic routing and a network which is being advertised by this IGP is specifying  a different path to what you want your rtr to take so in this case you could specify a more specific longer match on this network in a form of a static route which will take precedence over the igp advertised route.

[Richard Burts · Accepted solution]

The question in the original post is basically asking for comparison of static routing vs dynamic routing. We can make some generalizations about both of them.

Static Routing pro

simple to implement and simple to support

does not consume bandwidth for routing updates

does not consume memory for tables to store results of updates

does not consume cpu cycles to process updates

Static Routing con

does not react to changes in network topology and requires manual intervention to adjust to changes in topology

requires manual entry of every route in the network on every router in the network, so scaling to support larger networks is a challenge

Dynamic routing pro

does react dynamically to changes in topology

when there are multiple paths toward the destination can choose the optimum path

can advertise to all other routers in the routing domain about locally available paths

does scale more easily to support larger networks

Dynamic routing con

does consume bandwidth for advertisements

does consume memory to store information learned from other routers

does consume cpu cycles to process routing updates

has more sophisticated logic and can require more skilled operators to support

can be a challenge when some devices in a network do support a particular routing protocol while other devices in that network do not support that protocol

Having made these points choosing the most appropriate alternative really depends on an accurate understanding of the local environment, topology, and what are the real requirements for the network.

HTH

Rick