Subject: Re: IPv6 address space shortages (was: Re: A simple question)

From: "J. Noel Chiappa" <[email-masked]>
Date: Tue, 29 Apr 2003 20:52:44 -0400

> From: S Woodside <[email-masked]>

    > For purposes of geographic routing

The Multi6 WG just went over geographic addressing again, for about the 17th
time in the IETF (I seem to recall previous go-rounds on it in CIDRD and
IPng), and finally left off talking about it, on the grounds that there were
enough people against it that it was extremely unlikely there would ever be
rough consensus for it.

I suggest the same calculation ought to occur in this forum, i.e. that
there's no point discussing geographic addressing, since there's never going
to be rough consensus for it.

	Noel
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---

From: "Tony Hain" <[email-masked]>
Date: Tue, 29 Apr 2003 18:10:24 -0700

S Woodside wrote:
> ...
> 44 bits are provider independent and encode GPS coordinates. 
> It's enough to have accuracy to roughly 10 meter squares. 

The 04 version reduced that to 6.4 m, but your point about it being
somewhat course is valid. I stopped at 44 bits because the goal was
creating a /48. If that is expanded to a /52 you are looking at > .5 m
resolution. While this is possible to encode, the publicly available
gear is not capable of measuring that accurately.

> BUT ... that doesn't consider altitude.  

Depending on the intended use, that can be further encoded in the
remaining bits to create a unique /64 per cubic .5 m, 2 km deep. 

> In addition, it's quite easy to see that 10 
> meter squares may be a little bit too big for some purposes, even if 
> you're just talking about individual homes. Also, it doesn't 
> provide a 
> mechanism to define an area rather than a point. I could go on.
> 
> So it's clear at least to me that under this scheme there is 
> not enough 
> space in IPv6 to do proper justice to georouting.

We have the option of using longer than /64 prefixes if necessary. I
would prefer not to go there, but given a unique need it could be done.

Tony

> 
> simon
> 
> 
> [1] http://www.ietf.org/internet-drafts/draft-hain-ipv6-pi-addr-04.txt
> 
> 
> --
> www.simonwoodside.com -- 99% Devil, 1% Angel
> 
>