12-19-2006 09:14 AM - edited 03-03-2019 03:05 PM
Currently I have 2 DS3's to two different providers (ATT & Broadwing). I am turning up a third circuit which is an OC-3 to ATT (AS 7018). Right now I am using AS-Prepending on my /24's to successfully balance inbound traffic on the two DS3's. However, it doesn?t appear that I can prepend on a per neighbor (per circuit) basis, I can only prepend on an AS. How can I enforce inbound traffic ratios on the ATT DS3 and OC-3? Any configuration recommendations?
FYI: I cannot do a flash-cut so taking down the ATT DS3 is not an option at this time. I may however, make the DS3 a backup.
-JGR
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12-19-2006 03:37 PM
You are exactly correct. I though I had responded on this post.. maybe I got distracted and didn't hit post.
You can also prepend the AS as many times as you want and prepend a different number of times on different links. You only need 1 when the neighbors are the same AS when they are different you are safer doing more. I think I normally do 3 to make sure there is not a extra AS or 2 between the 2 isps. I assume some ISP have a limit so I wouldn't go too crazy with prepend.
12-19-2006 09:25 AM
check this URL if it gives you any clue.
http://www.cisco.com/warp/public/459/40.html#conf5
rate if it helps ....
12-19-2006 02:49 PM
I'm gathering that the answer may be that I can prepend the AS from ATT. This can be done because I can regulate the prepending on a per neighbor basis.
router bgp 12345
neighbor A.T.T.1 remote-as 7018
neighbor A.T.T.1 route-map localonly out
neighbor A.T.T.2 remote-as 7018
neighbor A.T.T.2 route-map oc-3-local-prepend out
neighbor B.W.G.1 remote-as 6395
neighbor B.W.G.1 route-map broadwing-out out
!
route-map oc-3-local-prepend permit 10
set as-path prepend 12345
!
12-19-2006 03:37 PM
You are exactly correct. I though I had responded on this post.. maybe I got distracted and didn't hit post.
You can also prepend the AS as many times as you want and prepend a different number of times on different links. You only need 1 when the neighbors are the same AS when they are different you are safer doing more. I think I normally do 3 to make sure there is not a extra AS or 2 between the 2 isps. I assume some ISP have a limit so I wouldn't go too crazy with prepend.
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