expectations for bgp peering?

Jon Lewis jlewis at lewis.org
Wed Jan 21 13:17:24 UTC 2009

On Tue, 20 Jan 2009, mike wrote:

> So I am just wondering what my expecations should be in a bgp peering 
> scenario where I am multihomed with my own ASN and arin assigned ip space. At 
> issue is the fact that my backup isp forced me to use ebgp multihop to peer 
> with a router internal to their network and not the border router I am 
> directly attached to, and secondly, that they say I am not allowed to prepend 
> at all - they will do it for me, and from the looks of things they have 
> established a route-map that just prepends their AS 6 times to my 
> announcement.

Assuming you're getting full routes from this provider, I wouldn't be 
surprised if the multihop is required because their router you're 
connected to doesn't have or can't handle full BGP routes.  I've done this 
with customers in the past when they were connected to routers that didn't 
have the RAM for full routes.

As for the "you're not allowed to prepend" thing, have you experimented to 
see what happens if you try?  Unless they're giving you special pricing 
based on the idea that they're providing you with strictly backup transit, 
they shouldn't be doing the prepending (unless you've asked them to or 
used communities to tell them to).

>   This smells of bad engineering. I have looked up the bgp report for my 
> provider and they have 0 downstream AS's, and the week that this project has 
> taken (and it's still not up and working) has left me with less than absolute 
> confidence in the provider. I want to know if anyone has an opinion on ebgp

Only a week?  I've seen BGP turnups take much longer...not that they 

  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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