Subject: Re: WG ACTION: 2 weeks to discuss [LL63] Text could be more specific

From: Stuart Cheshire <[email-masked]>
Date: Thu, 6 May 2004 22:56:02 -0700

>Requested Change:
>TEXT NEEDED

Replace

   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.

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

with just

   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.

Stuart Cheshire <[email-masked]>
 * Wizard Without Portfolio, Apple Computer, Inc.
 * www.stuartcheshire.org

---

From: "Philip Nye" <[email-masked]>
Date: Fri, 7 May 2004 12:16:54 -0000

> From: "Stuart Cheshire" <[email-masked]>
> 
> Replace
> 

This is omitting a specific recommendation as well as the unspecified example you objected to.

Whether just one or more implementations have made the mistake is irrelevant - it has been established as a mistake and useful guidance is provided.

However, this reads to me like a worry that unspecified "bad" former implementations may become erroneously associated with particular companies.

If this is the case, I could accept changing the first part of the offending paragraph:

   significantly reduced.

To:

   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.

Philip