Subject: Re: [core] Ben Campbell's No Objection on draft-ietf-core-block-19: (with COMMENT)

From: "Ben Campbell" <[email-masked]>
Date: Mon, 02 May 2016 16:07:42 -0500

Hi,

I think this addresses most of my comments, save the ones I already said 
I would not push. But I want to make sure I understand one point 
correctly (below):

On 29 Apr 2016, at 14:03, Carsten Bormann wrote:

[...]

>
> Reinforced by new text in the intro to section 2 (page 5).
>
>> - 2.5, 2nd paragraph, last sentence:
>> Should I read this to mean that the reduction in block size is
>> retroactive? That could use some elaboration. (I thought I read 
>> comments
>> in the examples suggesting such a reduction would _not_ be 
>> retroactive).
>
> I'm still not sure how to address this.

Let me restate the question in the form of an example.

Let's say a client requests a block size of N, and receives the block 0. 
But the server
indicates a preference for a block size if N/2. The client honors that 
preference on the next transfer. Is the next block numbered 1 or 2? I 
understand from this sentence the answer would be the latter. That seems 
to indicate the first block is recounted as 2 blocks--which is what I 
mean by retroactive.

But I _thought_ I had read text elsewhere in the document indicating the 
block numbering would stay the same, implying that the client would 
count a block 0 of size N and a block 1 of size N/2. But I cannot find 
that text now, and may have misread something. The rest of the document 
is pretty clear that block sizes all have to be the same. So this is 
probably okay as it is.

[...]