Subject: WG ACTION: 1 week continued discussion [LL63] Text should be more explicit

From: Erik Guttman <[email-masked]>
Date: Tue, 25 May 2004 17:55:28 +0200 (CEST)

LL63:

This issue remains open for discussion till June 2, 2004.

Note that the text in this section was created as a result of
collaboration with Ted Lemon and others in the DHC WG.  We cannot view
it as having been added erroneously or accidentally.

Please indicate which of the following options you prefer.

A) Leave the text as

   A device that implements both IPv4 Link-Local and a DHCPv4 client
   should not alter  the behavior of the DHCPv4 client to accommodate
   IPv4 Link-Local  configuration. In particular configuration of an
   IPv4 Link-Local address,  whether or not a DHCP server is currently
   responding, is not sufficient  reason to unconfigure a valid DHCP
   lease, to stop the DHCP client from  attempting to acquire a new IP
   address, to change DHCP timeouts or to  change the behavior of the
   DHCP state machine in any other way.

   Several early implementations of IPv4 Link-Local have modified the
   DHCP  state machine in an attempt to make IPv4 Link-Local more
   reliable, and the  field experience we have gained from this has
   shown that it does not work  - reliability of DHCP service is
   significantly reduced.   If increased reliability of IPv4 Link-Local
   is desired, we recommend that the IPv4 Link-Local state machine track
   the DHCP client state machine and, in cases where it is not certain
   that the DHCP-assigned address is correct, the  IPv4 Link-Local state
   machine acquire an IPv4 Link-Local address without causing the DHCP
   state machine to relinquish its address.

B) Replace the text in A) with

   A device that implements both IPv4 Link-Local and a DHCPv4 client
   should not alter the behavior of the DHCPv4 client to accommodate
   IPv4 Link-Local configuration. In particular configuration of an
   IPv4 Link-Local address, whether or not a DHCP server is currently
   responding, is not sufficient reason to unconfigure a valid DHCP
   lease, to stop the DHCP client from attempting to acquire a new IP
   address, to change DHCP timeouts or to change the behavior of the
   DHCP state machine in any other way.

C) Replace the text in A) with

   A device that implements both IPv4 Link-Local and a DHCPv4 client
   should not alter  the behavior of the DHCPv4 client to accommodate
   IPv4 Link-Local  configuration. In particular configuration of an
   IPv4 Link-Local address,  whether or not a DHCP server is currently
   responding, is not sufficient  reason to unconfigure a valid DHCP
   lease, to stop the DHCP client from  attempting to acquire a new IP
   address, to change DHCP timeouts or to  change the behavior of the
   DHCP state machine in any other way.

   Field experience has shown that modifying the DHCP state machine in
   an attempt to make IPv4 Link-Local more reliable does not work -
   reliability of DHCP service is significantly reduced.  If increased
   reliability of IPv4 Link-Local is desired, we recommend that the
   IPv4 Link-Local state machine track the DHCP client state machine
   and, in cases where it is not certain that the DHCP-assigned
   address is correct, the IPv4 Link-Local state machine acquire an
   IPv4 Link-Local address without causing the DHCP state machine to
   relinquish its address.

D) Replace A) with

   As documented in Appendix A, early implementations of IPv4
   Link-Local have modified the DHCP state machine.  Field experience
   shows that these modifications reduce the reliability of the DHCP
   service.

   A device that implements both IPv4 Link-Local and a DHCPv4 client
   should not alter the behavior of the DHCPv4 client to accommodate
   IPv4 Link-Local configuration. In particular configuration of an
   IPv4 Link-Local address, whether or not a DHCP server is currently
   responding, is not sufficient reason to unconfigure a valid DHCP
   lease, to stop the DHCP client from attempting to acquire a new IP
   address, to change DHCP timeouts or to change the behavior of the
   DHCP state machine in any other way.

   Further discussion of this issue is provided in [DNAv4]."

Erik Guttman
ZEROCONF WG Chair

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From: "Philip Nye" <[email-masked]>
Date: Wed, 26 May 2004 11:18:14 +0100

> Please indicate which of the following options you prefer.

First choice D, second C, third A, all are acceptable to me. B is not as it loses useful advice.

Philip