Re: FW: [dhcwg] co-existence of temp and normal addresses

Thomas Narten <> Tue, 09 April 2002 17:42 UTC

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To: "Bernie Volz (EUD)" <>
Subject: Re: FW: [dhcwg] co-existence of temp and normal addresses
In-Reply-To: Message from "Bernie Volz (EUD)" <> of "Mon, 08 Apr 2002 09:23:37 CDT." <66F66129A77AD411B76200508B65AC69B4D1D4@EAMBUNT705>
Date: Tue, 09 Apr 2002 10:29:48 -0700
From: Thomas Narten <>
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> The only problem with this typing is that it presumes the client
> always knows what to ask for. In the cases we have today, that
> appears to be appropriate.

Right.  In the specific cases of Temporary and "normal" addresses, I
think the client does know which it wants and needs to treat them

> However, it is not clear that this would be the case down the road
> depending on how "type" is defined.

Thinking a bit more on this, I don't think a separate type field is
needed in the IA itself. Just let the DHCP option number itself serve
that purpose. I.e., it's perfectly OK to assign different option
numbers for the temporary vs. normal address case. The actual format
of the options could be the same, if that is what makes sense.

> For example, one might ask
> whether we should split the "normal" case in two and have
> "normal-global" and "normal-site".

I would argue no, for the reason that the client shouldn't be
distinguishing these cases. I.e, the client just gets a set of
addresses (0, 1, 2 or  more globals, 0 or more site-locals) and
assigns them to the interface. The client shouldn't care about how
many or what type. It just uses the ones assigned to it.

So I think we are in agreement that generalizing this is a potentially
troubling direction.

However, in the specific case of temporary address vs. non-temporary,
the client may well have more specific knowledge about how they are
used (e.g., the client may want to switch to a new temporary address
more frequently than another client, so this should be under client


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