On Dec 24, 2011, at 6:48 AM, Glen Kent wrote: >> >> SLAAC only works with /64 - yes - but only if it runs on Ethernet-like >> Interface ID's of 64bit length (RFC2464). > > Ok, the last 64 bits of the 128 bit address identifies an Interface ID > which is uniquely derived from the 48bit MAC address (which exists > only in ethernet). >
Not exactly. Most media have some form of link-layer addressing. For Firewire, it's native EUI-64. For Ethernet, it's EUI-48 MAC addresses. For token ring, I believe there are also EUI-48 addresses. For FDDI (Remember FDDI?) I believe it was EUI-48 addresses. ATM and Frame Relay also have EUI addresses built in to their interfaces (though I don't remember the exact format and am too lazy to look it up at the moment). >> SLAAC could work ok with /65 on non-Ethernet media, like a >> point-to-point link whose Interface ID's length be negotiated during the >> setup phase. > > If we can do this for a p2p link, then why cant the same be done for > an ethernet link? > I'm not so sure the statement above is actually true. Owen > Glen > >> >> Other non-64 Interface IDs could be constructed for 802.15.4 links, for >> example a 16bit MAC address could be converted into a 32bit Interface >> ID. SLAAC would thus use a /96 prefix in the RA and a 32bit IID. >> >> IP-over-USB misses an Interface ID altogether, so one is free to define >> its length. >> >> Alex >> >>> >>> Regards, K. >>> >> >>
