What routing protocols will you use in a network design project?

Q: What routing protocols will you use in a network design project?

Meet the expert Thomas A. Limoncelli is an internationally recognized author and speaker. He is best known for his books The Practice of System and Network Administration (with Christina J. Hogan and Strata R. Chalup), Time Management for System Administration and The Complete April Fools RFCs (with Peter J. Salus). Read more about Tom and his books at Everything Sysadmin.

[In a network design project] we have different networks and different network segments, and the routers need to know how to route between them. Because these segments come and go, we [usually] can't just use some kind of static configuration. There is a static routing configuration called static routing, where you just hand-configure every router to know how to get to every other network , and it's common in very small networks with less than about five routers.

But once you get larger than that, you're going to need to pick a routing protocol to manage those routes for you. Two common ones are OSPF and EIGRP,

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 and there are tradeoffs between the two. OSPF is an open standard and it's supported by many vendors. EIGRP has some benefits over OSPF: it's a little faster [to converge] when there's a link down. But EIGRP is only available on Cisco routers, so if you use EIGRP, you're locked into Cisco products, whereas OSPF will enable you to choose from a variety products and companies.