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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: IPv6 daydreams
--- David Conrad <[email protected]> wrote: > On Oct 17, 2005, at 10:39 PM, Paul Jakma wrote: > >> Wrong issue. What I'm unhappy about is not the > size of the > >> address - you'll notice that I didn't say "make > the whole address > >> space smaller." What I'm unhappy about is the > exceedingly sparse > >> allocation policies > > You can allocate to 100% density on the network > identifier if you > > want, right down to /64. > > I believe the complaint isn't about what _can be_ > done, rather what > _is being_ done. Yes and yes. I am certainly complaining about what *is* being done. See below for my bigger issue. > > > The host identifier simply is indivisible, and > just happens to be > > 64bit. > > I've always wondered why they made a single > "address" field if the > IPv6 architects really wanted a hard separation > between the host > identifier and the network identifer. Making the > "address" a > contiguous set of bits seems to imply that the > components of the > "address" can be variable length. Now we're cooking with gas: what we've learned from MAC addresses is that it's really nice to have a world-unique address which only has local significance. The /64 "host identifier" is a misnomer: there are folks who use /127s and /126s for point-to-point links, and there are all sorts of variable length masks in use today. The whole reason for a /64 to be associated with a host is to have enough room to encode MAC addresses. I ask again - why exactly do we want to do this? Layer-2 works just fine as a locally-significant host identifier, and keeping that out of layer-3 keeps everything considerably simpler. -David Barak- -Fully RFC 1925 Compliant- __________________________________ Yahoo! Music Unlimited Access over 1 million songs. Try it free. http://music.yahoo.com/unlimited/
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