On Thu, Jul 30, 2009 at 12:22:27AM -0400, Barton F Bruce wrote: > So what is wrong with a /31? We use /30s but if you are short on IP space, > look at using /31 rather than /30 links. Cuts your space usage in half.
/31's are only defined for point-to-point links. Ethernet isn't considered PtP in general.. Many devices won't accept a /31 on anything but a PtP WAN media type link. (or not at all).