Re: [dhcwg] comments on draft-ietf-dhc-lifetime-01.txt

Stig Venaas <> Thu, 12 August 2004 09:39 UTC

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Date: Thu, 12 Aug 2004 11:31:21 +0200
From: Stig Venaas <>
To: "JINMEI Tatuya / ?$B?@L@C#:H" <>
Subject: Re: [dhcwg] comments on draft-ietf-dhc-lifetime-01.txt
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On Wed, Aug 11, 2004 at 11:12:16PM +0900, JINMEI Tatuya / ?$B?@L@C#:H wrote:
> >>>>> On Tue, 3 Aug 2004 13:20:22 -0400, 
> >>>>> "Bernie Volz" <> said:
> > I too would recommend that this option only be used with stateless
> > (Information-Request/Reply). It does not apply to stateful - in stateful,
> > even if there are no T1/T2 times (i.e., no IA_NA option), the client will
> > need to do something when it no longer has addresses so it will get new
> > information from the server.

I think stateless only might be too strict.

One example I have in mind is:

If a client sends a request message to obtain addresses and other config
options and it does not get any addresses but receives other config
data. Then the client may use those options and not make a
Request/Information-Request, right? You say client needs to do something
when it no longer has addresses, but if you have IPv4 addresses, and the
only IPv6 DHCP server says it has no addresses, then I think it's ok for
the client to just use what it got without switching to stateless mode,
and at some later point make a new Request, still not using stateless

How about saying this instead?:

   The lifetime option is mainly intended for Stateless DHCP service as
   specified in RFC 3736.  If the client receives IA Address options
   containing lifetimes, the lifetime option should be ignored.  The
   client should get updated configuration data from the server when it
   renews the addresses.

Another thing I'm wondering about is if T1, T2 are zero or infinity. I
think the lifetime option might make sense then. In 3315 it says:

   If T1 or T2 is set to 0 by the server (for an IA_NA) or there are no
   T1 or T2 times (for an IA_TA), the client may send a Renew or Rebind
   message, respectively, at the client's discretion.

If you get e.g. 0, it might be good to have some sort of lifetime for
the other data, and I guess you might then do renew/rebind when the
lifetime expires.

> I tend to agree.  In addition to the above points, I'd like to point
> out that in the stateful exchanges the server can initiate update by
> Reconfigure - at least in theory.

Yes, if clients support it...


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