best practice for advertising peering fabric routes

Joe Abley jabley at
Wed Jan 15 17:35:51 UTC 2014

On 2014-01-15, at 12:04, Jim Shankland <nanog at> wrote:

> On 1/14/14, 8:41 PM, Patrick W. Gilmore wrote:
>> I repeat: NEVER EVER EVER put an IX prefix into BGP, IGP, or even static route. An IXP LAN should not be reachable from any device except those directly attached to that LAN. Period.
> So ... RFC1918 addresses for the IXP fabric, then?

I've heard apparently non-drunk people suggest IPv6 link-local addresses as BGP endpoints across exchanges, too.

> (Half kidding, but still ....)

RFC 6752.

One observation on this thread: some networks have customers who react badly to unusual things seen in traceroute. Sometimes the margin on an individual customer is low enough that one support call displaces any profit you were going to make off them this month.

It's understandable to me that such network operators would choose to carry IXP routes internally in order to avoid that potential support burden.

I don't pretend to have any universal good/bad answer to the original question, though. I don't think the world is that simple.

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