Re: purpose of m/o bit

[Erik Nordmark <erik.nordmark at sun.com>]

Ralph Droms wrote:
> Seems to me I'm hearing two requirements out of this thread:
>
> 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

I the case where the network admin wants to do stateless address 
autoconfiguration and has DHCP available for ICB, how inefficient will 
the above be?

Wouldn't this mean that the hosts which are implemented to handle HCB as 
well as ICB, would always try with a Solicit i.e. they would end up 
doing a 4 packet DHCP exchange. Had the host known that HCB was not 
available, a 2 packet exchange would have been sufficient.

Thinking about hosts moving between different links, the difference 
between 4 and 2 packets for DHCP ICB might matter.

Hence my question how useful it would be to have
3) Ability for the host to find out from the RA that it doesn't need to 
bother with HCB since only ICB is available on the network.

   Erik

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