nanog mailing list archives
Re: IPv6 daydreams
From: David Barak <thegameiam () yahoo com>
Date: Wed, 19 Oct 2005 20:39:11 -0700 (PDT)
--- David Conrad <drc () virtualized org> wrote:
On Oct 17, 2005, at 10:39 PM, Paul Jakma wrote:Wrong issue. What I'm unhappy about is not thesize of theaddress - you'll notice that I didn't say "makethe whole addressspace smaller." What I'm unhappy about is theexceedingly sparseallocation policiesYou can allocate to 100% density on the networkidentifier if youwant, 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, andjust happens to be64bit.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/
Current thread:
- Re: IPv6 daydreams, (continued)
- Re: IPv6 daydreams Paul G (Oct 17)
- Message not available
- Re: IPv6 daydreams Peter Dambier (Oct 17)
- Re: IPv6 daydreams Mark Smith (Oct 17)
- Re: IPv6 daydreams Randy Bush (Oct 17)
- Re: IPv6 daydreams Mark Smith (Oct 17)
- Re: IPv6 daydreams Kevin Loch (Oct 17)
- Re: IPv6 daydreams David Barak (Oct 17)
- Re: IPv6 daydreams Jeroen Massar (Oct 17)
- Re: IPv6 daydreams Paul Jakma (Oct 17)
- Re: IPv6 daydreams David Conrad (Oct 18)
- Re: IPv6 daydreams David Barak (Oct 19)
- Re: IPv6 news Michael . Dillon (Oct 17)