Subject: RE: [mobile-ip] Connectathon 2003 issues for MIPv6 draft-20

From: Erik Nordmark <[email-masked]>
Date: Sun, 16 Mar 2003 19:36:31 +0100 (CET)

> Also, with how the definition of the site-local prefix is being changed so
> that it shares the low-order 48 bits (i.e. fec0:xxxx:xxxx:xxxx, the
> "xxxx:xxxx:xxxx" part is what I'm referring to) of the prefix with a global
> scope prefix assigned to the same link,

I haven't seen any such discussion on the ipng list.

  Erik

---

From: "Ed Remmell" <[email-masked]>
Date: Sun, 16 Mar 2003 18:37:00 -0800

Erik -

I was a little disappointed when I saw it first, but it grew on me and I've
decided I like the change (it is easier for administrators). We were using
the unused bits in the site-local scope prefix to internally store the
32-bit scope ID (FreeBSD does this too), so we could be a multi-sited node
(of course, it was stripped out when sent on the wire). Now, it seems like
the only way for us to be multi-sited is to add an additional 32-bit scope
ID prefix to the front of the IPv6 address prefix in our routing tree, since
we have a host implementation of IPv6 we really don't need to go there yet.
Note that we are still able to do this hack with the link-local scope
prefix.

From draft 10 of the addressing architecture update
(draft-ietf-ipngwg-addr-arch-v3-10.txt):

   Site-Local addresses have the following format:

   |   10     |
   |  bits    |         54 bits         |         64 bits            |
   +----------+-------------------------+----------------------------+
   |1111111011|        subnet ID        |       interface ID         |
   +----------+-------------------------+----------------------------+

   Site-local addresses are designed to be used for addressing inside of
   a site without the need for a global prefix.  Although a subnet ID
   may be up to 54-bits long, it is expected that globally-connected
   sites will use the same subnet IDs for site-local and global
   prefixes.

Thanks.
- Ed

> -----Original Message-----
> From: Erik Nordmark [mailto:[email-masked]]
> Sent: Sunday, March 16, 2003 10:37 AM
> To: Ed Remmell
> Cc: Jari Arkko; Samita Chakrabarti; [email-masked]
> Subject: RE: [mobile-ip] Connectathon 2003 issues for MIPv6 draft-20
>
>