Hello Keith,
From your BGP videos I got a very good understanding of how we can influence traffic from remote-as into our AS. I had a couple of questions.
Question-1]
What are some of the disadvantages of using AS-PATH PREPEND?
Question-2]
Apart from MED and AS-PATH Prepend, is there any other way we can influence traffic from remote-as into our AS ?
Question-3]
Similarly to influence traffic outbound from our AS to remote-as, Apart from weight and Local Pref can we use anything else?
Questions-4]
What are some of the limitations of BGP split Horizon rule ?
Kindly advise.
Best,
Abhishek Gupta.
Hi Abhishek,
Question-1
What are some of the disadvantages of using AS-PATH PREPEND?
-----The most common disadvantage is that many ISPs have a policy that they do not accept prepended prefixes. So if you weren’t aware of this policy and sent a prepended prefix it would be dropped by your peer.
Question-2
Apart from MED and AS-PATH Prepend, is there any other way we can influence traffic from remote-as into our AS ?
----You could try modifying the BGP Origin Code. “IGP” is always preferred over “Incomplete”.
Question-3
Similarly to influence traffic outbound from our AS to remote-as, Apart from weight and Local Pref can we use anything else?
—I haven’t tried this myself, but I believe received routes can also be prepended
Questions-4
What are some of the limitations of “BGP split Horizon rule” ?
----If you don’t use Route-Reflectors or BGP Confederations the BGP Split-Horizon rule will force you to have a full-mesh of iBGP peers within your autonomous system. This could result in a LOT of TCP connections to create this full-mesh of iBGP peering.