with the advent of vlan tags, the whole idea of CSMA for IXP networks is passe.
just put each pair of peers into their own private tagged vlan and let one of
them allocate a V4 /30 and a V6 /64 for it. as a bonus, this prevents third
party BGP (which nobody really liked which sometimes got turned on by mistake)
and prevents transit dumping and/or "pointing default at" someone. the IXP no
longer needs any address space, they're just a VPN provider. shared-switch
connections are just virtual crossconnects.
--
Paul Vixie
