On Thu, Apr 4, 2013 at 1:43 PM, Randy Bush <ra...@psg.com> wrote: >>> Even if the exchange does not advertise the exchange LAN, it's >>> probably the case that it is in the IGP (or at least IBGP) of >>> everyone connected to it, > > yikes! this is quite ill-advised and i don't know anyone who does > this, but i think all my competitors should. >
Its more common than uncommon. At WIX (Wellington), 64 out of 93 members will carry packets destined to APE (Auckland Exchange). (source: http://conference.apnic.net/__data/assets/pdf_file/0018/50706/apnic34-mike-jager-securing-ixp-connectivity_1346119861.pdf) and this is just New Zealand! Just checked a few exchanges, not just are the IXP ranges being carried, they're being leaked: Equinix SG: $ bgpctl show rib 202.79.197.0/24 flags: * = Valid, > = Selected, I = via IBGP, A = Announced origin: i = IGP, e = EGP, ? = Incomplete flags destination gateway lpref med aspath origin 202.79.197.0/24 100 0 13335 23947 23947 ? 202.79.197.0/24 100 0 13335 10026 i Any2 LA: bgpctl show rib 206.223.143.0/24 flags: * = Valid, > = Selected, I = via IBGP, A = Announced origin: i = IGP, e = EGP, ? = Incomplete flags destination gateway lpref med aspath origin 206.223.143.0/24 100 0 13335 9304 i 206.223.143.0/24 100 0 13335 9304 i 206.223.143.0/24 100 0 13335 4635 9304 i 206.223.143.0/24 100 0 13335 9304 i >> I have experience of several networks where that is not the case. IGP >> carries routes for loopback and internal-facing interfaces; > > i have seen some carry external because, for some reason, they do not > want to re-write next-hop at the border. > > randy >