North American Network Operators Group|
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical
Re: It's Ars Tech's turn to bang the IPv4 exhaustion drum
On 8/19/08 1:36 PM, "Nathan Ward" <nanog@xxxxxxxxx> wrote: > 64 bits is not a magical boundary. > > 112 bits is widely recommended for linknets, for example. > > 64 bits is common, because of EUI-64 and friends. That's it. > There is nothing, anywhere, that says that the first 64 bits is for > routing. Actually, there is text that says so: RFC4291: IPv6 Addressing Architecture, section 2.5.1 " For all unicast addresses, except those that start with the binary value 000, Interface IDs are required to be 64 bits long and to be constructed in Modified EUI-64 format." The fact that most implementations ignore this is a different story. In practice, many routers require the packet to go twice in the hardware if the prefix length is > 64 bits, so even though it is a total waste of space, it is not stupid to use /64 for point-to-point links and even for loopbacks! - Alain.