What is the most important routing protocols to know for each of these environments: small business, medium business, corporate business, and ISPs?
I understand that each environment probably uses different protocols and I'd like to know which are most commonly used in each, assuming that they are not outdated environments.
I'm guessing it gets more vague as you move up the ladder, but I'm curious to know what people have seen out there in the business world anyway.
(BTW, I'm a newb. If it isn't already obvious :)