Re: Using /126 for IPv6 router links

[Christopher Morrow <morrowc.lists () gmail com>]

On Sat, Jan 23, 2010 at 9:03 PM, Mark Smith
<nanog () 85d5b20a518b8f6864949bd940457dc124746ddc nosense org> wrote:
> On Sat, 23 Jan 2010 20:08:05 -0500
> Christopher Morrow <morrowc.lists () gmail com> wrote:
>
> > On Sat, Jan 23, 2010 at 7:52 AM, Mathias Seiler
> > <mathias.seiler () mironet ch> wrote:
> > > Hi
> > >
> > > In reference to the discussion about /31 for router links, I d'like to know what is your experience with IPv6 in 
> > > this regard.
> > >
> > > I use a /126 if possible but have also configured one /64 just for the link between two routers. This works great 
> > > but when I think that I'm wasting 2^64 - 2 addresses here it feels plain wrong.
> > >
> > > So what do you think? Good? Bad? Ugly? /127 ? ;)
> >
> > <cough>draft-kohno-ipv6-prefixlen-p2p-00.txt</cough>
> >
> > (<http://tools.ietf.org/id/draft-kohno-ipv6-prefixlen-p2p-00.txt>)
>
> <cough>Internet Draft</cough>
>
> No disrespect to the people who've written it, however it's a draft at
> this point, not an RFC.

absolutely. so... if it's of interest, speak up (on the v6 wg  mailing
list) or let the authors know.

> The current IP Version 6 Addressing Architecture RFC (RFC4291) says,
>
> "  For all unicast addresses, except those that start with the binary
>   value 000, Interface IDs are required to be 64 bits long and to be
>   constructed in Modified EUI-64 format"
>
> If that draft is going to go anywhere, then I would expect there also
> needs to be a new version of RFC4291.

I believe the authors know this as well.

-Chris

> > why not just ping your vendors to support this, and perhaps chime in
> > on v6ops about wanting to do something sane with ptp link addressing?
> > :)
> >
> > -Chris