Subject: RE: I-D ACTION:draft-ietf-dhc-slp-05.txt

From: "Ryan Troll" <[email-masked]>
Date: Thu, 3 Dec 1998 13:32:16 -0500 (EST)

Currently, the directory agent option (78) is defined as a list of 4-byte IP
addresses.  How will this work in an IPv6 environment?

Since we are currently working on freeing up options due to the limited
number remaining, we may want to also consider making sure that options
being defined now will work for as long as possible.  When SLP servers begin
to be on IPv6 only machines, this option will no longer work.

One quick solution would be to redefine the list to contain a size byte
before every IP address.  At this time, the value of this size byte will
always be 4:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Code = 78   |    Length     |    Len = 4    |      a1       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      a2       |       a3      |       a4      |    Len = 4    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      a1       |       a2      |       a3      |      a4       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Len = 4    |       a1      |       a2      |     .....
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

In the future, when IPv6 addresses are being used, this can expand to the
appropriate length.

Yet another solution would be to add a prefix byte (just like the length),
but have it define the type of address that follows.  1 == IPv4, 2 == IPv6,
etc.  However, going this path starts to go down the suboption path, and may
require the IANA.

This is just a thought.  I could be way out there on this one, and a list of
IPv4 addresses will be good enough.  Not being sure, I thought I'd bring it
up for discussion.

-Ryan

---

From: Erik Guttman <[email-masked]>
Date: Thu, 3 Dec 1998 16:17:02 -0500 (EST)

Ryan,

Our use of IP addresses for configuration is entirely consistent with
other DHCP options, for instance RFC 2132 options 3, 4, 5, 6, 7, 8,
9, ...

Our intention is to use DHCPv6 options (see Type 16 DHCPv6 extension in 
draft-ietf-dhc-v6exts-10.txt) for configuring IPv6 nodes.  Please note
that there is now a version skew between draft-ietf-dhc-slp-05.txt and
the v6exts draft.  

draft-ietf-dhc-slp-05.txt has been greatly simplified and it is the
desire of the SVRLOC WG to see this draft go to WG last call in the 
DHC WG.  We need this document to advance to proposed standard in order
for our base SLPv2 specification and other documents (all of which have
gone through IESG last call) to advance to proposed standard.

Thanks,

Erik Guttman
SVRLOC WG chair

---

From: "Ryan Troll" <[email-masked]>
Date: Thu, 3 Dec 1998 16:27:30 -0500 (EST)

No problem.  Glad to see IPv6 has been thought about.

I'm a little behind on reading all of this, and am not fully aware of all of
the DHCPv6 changes.  Some, but not all.  This is one I haven't gotten to
yet.

Thanks,
-Ryan

> -----Original Message-----
> From: Erik Guttman [mailto:[email-masked]]
> Sent: Thursday, December 03, 1998 3:18 PM
> To: [email-masked]
> Cc: Multiple recipients of list
> Subject: RE: I-D ACTION:draft-ietf-dhc-slp-05.txt
>
>
>
> Ryan,
>