Subject: Re: purpose of m/o bit

From: Ralph Droms <[email-masked]>
Date: Wed, 01 Jun 2005 07:31:49 -0400

We need to agree on requirements before we try to engineer solutions.
Here is what I've heard as requirements:

1) Ability to indicate to a host "DHCP is not available on this link",
   with the expectation that the host won't send any DHCP messages

2) Ability for a host to get all desired and available DHCP
   configuration with a single DHCP message exchange
   - if a host wants HCB, it sends an HCB request (Solicit) and receives
     HCB and/or ICB replies
   - if a host wants ICB, it sends an ICB request (Information-request) 
     and receives ICB replies

1 is a requirement in scenarios with limited resources (e.g., wireless),
where polling for DHCP is unacceptable.  2 is a requirement to avoid
timeout delays or other complexity in getting ICB reply when host would
prefer HCB reply.

Comments?

- Ralph

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From: Iljitsch van Beijnum <[email-masked]>
Date: Wed, 1 Jun 2005 14:04:35 +0200

> We need to agree on requirements before we try to engineer solutions.

:-)

> Comments?

3 Ability to limit DHCP use to other configuration only

And, apparently:

4 Ability to do DHCP without having to configure routers

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From: Pekka Savola <[email-masked]>
Date: Wed, 1 Jun 2005 15:29:45 +0300 (EEST)

>   - if a host wants HCB, it sends an HCB request (Solicit) and receives

It would be even better to keep backward compatibility, i.e., not 
require extensions to ICB-only DHCP servers to support Solicits. 
Let's face it, those extensions always take time to specify, code and 
deploy, the admins will have to wait for new versions, etc.

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From: Ralph Droms <[email-masked]>
Date: Wed, 01 Jun 2005 08:36:23 -0400

Pekka - In theory, I agree.  In practice, it's early enough to make a
change before we have extensive deployments and the lack of backward
compatibility only affects a few deployments, where a host requesting
HCB would be satisfied with and ICB response.  So, I don't think
backward compatibility is as important as improving the protocol.

- Ralph