Subject: Re: FW: IP6 support in draft-parker-isis-wg-mib-00.txt

From: "Jitu Patel" <[email-masked]>
Date: Thu, 25 Feb 1999 12:09:45 -0800

You are right. Mike. I did hack up a set of TLVs to carry IPv6 information .
The V6 TLVs were a duplicate of the V4 TLVs

However I think we should take the opportunity to fix up some of the
problems we have with the V4 stuff. In particular the metric field should
extended to 4 bytes, we need bits to indicate what metrics are actually
present rather than having fields for all the metric types ( this will be a
bit like the BGP TLVs). The actual addressing information would a varaible
length prefix with the length of the prefix indicating the mask length.

    Jitu

-----Original Message-----
From: Mike Shand <[email-masked]>
To: Tony Li <[email-masked]>; [email-masked] <[email-masked]>
Cc: [email-masked] <[email-masked]>; [email-masked]
<[email-masked]>; [email-masked] <[email-masked]>;
[email-masked] <[email-masked]>; [email-masked] <[email-masked]>;
JPatel <[email-masked]>
Date: Thursday, February 25, 1999 2:16 AM
Subject: Re: FW: IP6 support in draft-parker-isis-wg-mib-00.txt

>At 02:02 25/02/1999 -0800, Tony Li wrote:
>
>>It turns out that there's just not that much stuff that's new an
>>interesting about carrying IPv6 addressing information.  Given the way
that
>>IS-IS is based, you would want to add a TLV.  This would contain what
would
>>look like a 'prefix'.  A longer one to be sure, but nothing that could
>>possibly qualify as 'new' or 'interesting'.  It's precisely because IPv6
is
>>IPv4 with 'more bits' that it doesn't really change the paradigm all that
>>much.
>>
>
>Sure, its completely trivial. But shouldn't we write down a TLV format for
>it, so that people can play with it if they want to. In fact I think Jitu
>Patel implemented something before he left DEC. We certainly talked about
>it. Jitu?
>
>The only vaguely interesting thing I can think of is that given that IPv6
>addresses seem to be somewhat sparse, there might be some opportunity for
>bit bumming in the 'prefix':-) Or not!
>
> Mike
>
>
>
>>Tony
>>
>

---

From: Tony Li <[email-masked]>
Date: Thu, 25 Feb 1999 15:36:57 -0800 (PST)

|  However I think we should take the opportunity to fix up some of the
|  problems we have with the V4 stuff. In particular the metric field should
|  extended to 4 bytes, we need bits to indicate what metrics are actually
|  present rather than having fields for all the metric types ( this will be a
|  bit like the BGP TLVs). The actual addressing information would a varaible
|  length prefix with the length of the prefix indicating the mask length.

Done.  Please see draft-ietf-isis-traffic-00.txt.  Excerpt:

======================================================================
   The proposed extended IP reachability TLV contains a new data
   structure, consisting of:
           4 bytes of metric information
           1 byte of control information, consisting of
                   1 bit of up/down information
                   1 bit indicating the existence of sub-TLVs
                   6 bits of prefix length
           0-4 bytes of IPv4 prefix
           0-250 optional octets of sub-TVLs, if present consisting of
                   1 octet of length of sub-TLVs
                   0-249 octets of sub-TLVs
======================================================================

Tony