[governance] IPv4-v6 - "coexistence" not transition - operational issues surfacing

[McTim]

On Thu, Feb 21, 2008 at 2:25 PM, Bertrand de La Chapelle
<bdelachapelle at gmail.com> wrote:
> Hi,
>
>
> On 2/21/08, McTim <dogwallah at gmail.com> wrote:
>
> IPv6 packet design HAD to be different from IPv4 packet design, hence,
> lack of backwards compatibility.
>
> But Randy Bush's slides say :
>
>
> "Incompatibility could have been avoided, e.g. if IPv6 had variable length
> addressing, IPv4 could have become the 32 bit variant"

IPv6 DOES have variable length in the architecture.

RFC 2374 says:

   "The specific type of an IPv6 address is indicated by the leading bits
   in the address.  The variable-length field comprising these leading
   bits is called the Format Prefix (FP)."

and:

"3.1 Aggregatable Global Unicast Address Structure

   The aggregatable global unicast address format is as follows:

     | 3|  13 | 8 |   24   |   16   |          64 bits               |
     +--+-----+---+--------+--------+--------------------------------+
     |FP| TLA |RES|  NLA   |  SLA   |         Interface ID           |
     |  | ID  |   |  ID    |  ID    |                                |
     +--+-----+---+--------+--------+--------------------------------+"

The 3 bits above "FP" on the left side of the 128 bits is "Format Prefix"

I think what Randy is referring to is that we are only using Unicast addresses
currently (1/8 of the total IPv6 address space).  The theory being
that if we stuff up, and have to start over, we will have 7/8ths of
the possible 3.4×1038 addresses.

Maybe he means RFC2526, Reserved IPv6 Subnet Anycast Addresses
(Proposed Standard)
You'll have to ask him what he means tho, as I can't be sure.

-- 
Cheers,

McTim
$ whois -h whois.afrinic.net mctim


>
> Must confess I'm not cognisant enough. Could you explain a bit further ?
>
> Best
>
> Bertrand
>
>
>
>
>
> On 2/21/08, McTim <dogwallah at gmail.com> wrote:
> > On Thu, Feb 21, 2008 at 1:44 PM, Bertrand de La Chapelle
> > <bdelachapelle at gmail.com> wrote:
> > > Hi all,
> > >
> > >
> > >
> > > On 2/21/08, McTim <dogwallah at gmail.com> wrote:
> > >
> > > There won't be A remedy. the 2 protocols were never designed to be
> > >  "interoperable".  There are a variety of "remedies" that will allow v4
> > > hosts to communicate with v6 hosts and vice versa.
> > >
> > > Can anyone explain why those who designed IPV6 did not think about the
> > > transition path and the necessary interoperability between both
> protocols ?
> >
> > They did think about the transition path:
> >
> > http://nislab.bu.edu/sc546/sc441Spring2003/ipv6/transition.htm
> >
> > in order to "Deploy more recent technologies" listed here:
> >
> > http://www.netbsd.org/docs/network/ipv6/
> >
> > IPv6 packet design HAD to be different from IPv4 packet design, hence,
> > lack of backwards compatibility.
> >
> > Don't worry, the sky is not falling, the Internet will not come
> > crashing to a halt, as some are suggesting.
> >
> > --
> > Cheers,
> >
> > McTim
> > $ whois -h whois.afrinic.net mctim
> >
>
>
>
>
> --
> ____________________
> Bertrand de La Chapelle
> Délégué Spécial pour la Société de l'Information / Special Envoy for the
> Information Society
> Ministère des Affaires Etrangères et Européennes/ French Ministry of Foreign
> and European Affairs
>  Tel : +33 (0)6 11 88 33 32
>
> "Le plus beau métier des hommes, c'est d'unir les hommes" Antoine de Saint
> Exupéry
> ("there is no better mission for humans than uniting humans")
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