best practice for advertising peering fabric routes

William Herrin bill at
Wed Jan 15 15:44:54 UTC 2014

On Tue, Jan 14, 2014 at 10:11 PM, Patrick W. Gilmore <patrick at> wrote:
> NEVER EVER EVER put an IX prefix into BGP, IGP, or even
> static route. An IXP LAN should not be reachable from any
> device not directly attached to that LAN. Period.
> Doing so endangers your peers & the IX itself. It is on the order
> of not implementing BCP38, except no one has the (lame,
> ridiculous, idiotic, and pure cost-shifting BS) excuse that they
> "can't" do this.

Hi Patrick,

I have to disagree with you. If it appears in a traceroute to
somewhere else, I'd like to be able to ping and traceroute directly to
it. When I can't, that impairs my ability to troubleshoot the all too
common can't-get-there-from-here problems. The more you hide the
infrastructure, the more intractable problems become for your

The IXP LAN should be reachable from every device on the ASes which
connect to it, not just the immediate router.

Bill Herrin

William D. Herrin ................ herrin at  bill at
3005 Crane Dr. ...................... Web: <>
Falls Church, VA 22042-3004

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