Hi Al,

(Snipping a bit of context)

> On 22 Mar 2022, at 20:51, MORTON JR., AL <[email protected]> wrote:
> 
>>> In other words, the set of wire image features that can cause
>>> differential treatment in an operator's network is equal to the set of
>>> wire image features that are freely observable by that operator.
>> see above. there are many reasons a network operator would look at her
>> packets in order to diagnose problems not of her making.
>> 
>> --
>> P Vixie
> [acm] 
> 
> I think Paul is on the right track with this last sentence. There are several 
> limiting assumptions in this thread about operator activities:
> 
> + mid-path observations are only one of many ways to contribute to network 
> management. Launching QUIC connections from hosts under operator control is 
> another. Successful QUIC analysis seems to require different methods than 
> with TCP, and that's fine.

This is entirely missing; indeed, the document treats active measurement 
techniques (which I think are quite promising for management of encrypted 
transports) as implicitly out of scope. I’m not sure it makes sense to expand 
the scope of this doc (intended as a user’s guide to the wire image) in last 
call, but perhaps we should add text to make this scope explicit.

> + the "operator that wants to support QUIC" case seems to be an unexpected 
> role (so far). It would be useful to embrace this case in the manageability 
> draft, IMO.

The disconnect in this thread, I think, is related to how large we think the 
set of useful passive measurement actions requiring access to data not in the 
wire image is. I think that most of these tasks are things we think are useful 
with analogy to TCP, because we are *so used* to debugging TCP dynamics that we 
have unseen biases toward doing things that way. Indeed, I think the actual set 
tends toward empty, in part due to the (theoretical, perhaps tautological, but 
not at all meant as a straw man dismissal, apologies as it came off as such) 
analysis that the wire image you can see to troubleshoot is the same wire image 
your devices can see to break things. 

It would be interesting to dig into specifics to see how wrong I am. I’m not 
sure that’s in scope *this* document, though.

Thanks, cheers,

Brian

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