Subject: Re: [clue] Diff mechanism

From: Paul Kyzivat <[email-masked]>
Date: Mon, 01 Dec 2014 10:18:49 -0500

On 11/27/14 8:24 PM, Christian Groves wrote:
> Hello,
>
> Another issue that seemed to come up in the Hawaii meeting was whether
> the diff mechanism should be kept?
>
> I'm for keeping it in the protocol draft. If people don't want it to be
> mandatory then its use could be signalled through the OPTIONS message.

If it is to be optional, then there are two levels of optionality:

- optional to send
- optional to receive

ISTM that it would *always* be optional to send. (Certainly there are 
cases when it should not be used. And there are other cases where it 
would not be advantageous. The sender is really in the driver's seat on 
this, and could decide never to use it.)

So the key question would be whether it should be optional to receive. 
If so, then when a receiver indicates it doesn't want to receive it then 
the sender *couldn't* use it.

If it is optional to receive, then it is effectively optional to implement.

That would relieve the implementation cost of including it in the spec. 
But it might also reduce the level of scrutiny it gets as the spec is 
reviewed, and might end up being published with errors.

	Thanks,
	Paul