North American Network Operators Group

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Re: more-specifics via IX

  • From: Bradley Urberg Carlson
  • Date: Wed Oct 17 22:58:41 2007

Thanks for the suggestions.

On Oct 17, 2007, at 6:06 PM, Stephen Wilcox wrote:
well.. the problem of course is that you pull in the traffic from the aggregate transit prefix which costs you $$$ but then you offload it to the customer via a peering link for which you are not being paid

A bigger problem is that my IX peer pays less to my customer for transit. If my customer notices that transit traffic has been going around him, he may be grumpy. I prefer happy customers.

its a pain but you cant stop the customer from doing it.. you can however filter your customers prefix at the IX (an ASN filter would be easiest)

In this case, the IX peer had let their transit provider (my customer) source the routes, then later advertised their own routes at the IX using their own ASN (so inconsistent source-as, and my as-path filter missed them). I don't think they were trying to steal bandwidth; just sloppy networking.

I can either build a big import filter, dropping routes offered to me at the IX that are subnets of routes advertised to me by my transit customers (doesn't scale); or just audit customer routes versus peer routes periodically, looking for "bandwidth stealers". It sounds like that is the usual approach.