Subject: RE: DHCPINFORM

From: "Bernie Volz (EUD)" <[email-masked]>
Date: Thu, 29 Mar 2001 22:56:26 -0600

There's also a DHCP Solicit and Request message without an IA.

We should clarify what is and is not allowed/expected. Is a DHCPSolicit (or DHCPRequest) without an IA basically a DHCPINFORM? Or, do we not allow either of these to have no IA?

Also, wasn't the original purpose to use the DHCPRequest to allow a client to get just configuration parameters (no addresses) - when no IA? 

Having multiple was to something isn't good, IMHO.

Note with DHCPv4 there was NO way *NOT* to request an address without doing DHCPINFORM. With DHCPv6, that problem does not exist (do a Solicit or Request without an IA option).

- Bernie Volz

-----Original Message-----
From: Ted Lemon [mailto:[email-masked]]
Sent: Thursday, March 29, 2001 6:30 PM
To: DHCPv6 discussion list
Subject: DHCPINFORM

DHCPv4 has the DHCPINFORM message.   DHCPv6 does not.   We're solving
this (I think) with DHCPsolicit/DHCPadvertise messages with no IAs,
but I think this is confusing.   I think we should just have a DHCP
Information Request message that gets a DHCP Reply message with the
requested information.  If the group thinks this is a good plan, I'll
write it up.

			       _MelloN_

---

From: Ted Lemon <[email-masked]>
Date: Thu, 29 Mar 2001 22:25:26 -0700

> We should clarify what is and is not allowed/expected. Is a
> DHCPSolicit (or DHCPRequest) without an IA basically a DHCPINFORM? Or,
> do we not allow either of these to have no IA?

That's precisely the problem - it doesn't make sense for DHCPSolicit
to be a DHCPINFORM, but it doesn't make sense for DHCPRequest to be
DHCPINFORM either.   I think DHCP Information Request ought to be
seperate, because it's not a four-way handshake.

> Also, wasn't the original purpose to use the DHCPRequest to allow a
> client to get just configuration parameters (no addresses) - when no
> IA?

Yes, but my point is that we're overloading functionality on message
types for no apparent reason.

> Having multiple was to something isn't good, IMHO.

I agree.   Perhaps DHCPsolicit and DHCPrequest should not be valid
without at least one IA option.

> Note with DHCPv4 there was NO way *NOT* to request an address
> without doing DHCPINFORM. With DHCPv6, that problem does not exist (do
> a Solicit or Request without an IA option).

Right, but because of the four-way handshake, the protocol without the
DHCP Information Request message is confusing.   Certainly we can
define things in such a way that a careful read of the standard will
cause an implementor to do the right thing, but it might be better to
just define a seperate message for information requests not related to
IAs, and that way even a careless read of the spec will produce the
right results.

			       _MelloN_