As stated earlier static routing works well on small networks. At those networks get larger, routing takes longer, routing tables get very large, and general performance isn’t what it could be.

Topology is a concern as well. If all your computers are in one building, its much easier to stay with static routing longer. However, connecting a number of locations will be easier with the move to dynamic routing.

If you have a network of 20 computers, you can still likely use static routing. If those computers are in two or three locations, static routing will still be a good choice for connecting them. Also, if you just connect to your ISP and don’t worry about any special routing to do that, you are likely safe with just static routing.

If you have a network of 100 computers in one location, you can use static routing but it will be getting slower, more complex, and there won’t be much room for expansion. If those 100 computers are spread across three or more locations, dynamic routing is the way to go.

If you have 1000 computers, you definitely need to use dynamic routing no matter how many locations you have.

Hopefully this section has given you an idea of what results you will likely experience from different sized networks using different routing protocols. Your choice of which dynamic routing protocol to use is partly determined by the network size, and topology.