Keep the opinions coming guys.
there are certainly many opinions on this subject. However, the most important factor is - how flexible you wish to be? As you correctly point out, this is not an issue of what protocol are you going to be running inside your network. So, "IGP" is not an issue. The issue at hand is what routing protocol are you going to be running with your customers. The question you should ask yourself is - in what situations are you going to be running routing protocol with customers? In those situations, how are you going to implement things like loop prevention, path selection, load sharing and most importantly - how are you going to be carrying those routes in your network? Now, if you are clear how to do those things and you are comfortable with them in any given scenario - why would you limit yourself to on one thing? You could decide to be very flexible and do "whatever customer prefers", or you could limit yourself to one routing protocol. There are pros and cons in both cases. Personally, I prefer being able to be flexible with customers, but I perfectly understand larger operators wanting to have "standard package" that can be copy/pasted without much risk... -- Marko CCIE #18427 (SP) My network blog: http://cisco.markom.info/