OSPF vs IS-IS vs PrivateAS eBGP

Marko Milivojevic markom at markom.info
Wed Aug 19 13:13:17 CDT 2009

> 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...

CCIE #18427 (SP)
My network blog: http://cisco.markom.info/

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