[Rpm] [Make-wifi-fast] tack - reducing acks on wlans

[Toke Høiland-Jørgensen]

Michael Welzl <michawe at ifi.uio.no> writes:

>> On 20 Oct 2021, at 13:52, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
>> 
>> Michael Welzl <michawe at ifi.uio.no> writes:
>> 
>>>> On 20 Oct 2021, at 12:44, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
>>>> 
>>>> Michael Welzl <michawe at ifi.uio.no> writes:
>>>> 
>>>>>> On 20 Oct 2021, at 11:44, Toke Høiland-Jørgensen <toke at toke.dk> wrote:
>>>>>> 
>>>>>> Michael Welzl <michawe at ifi.uio.no> writes:
>>>>>> 
>>>>>>> Am I being naive? Why can't such an ARQ proxy be deployed? Is it just
>>>>>>> because standardizing this negotiation is too difficult, or would it
>>>>>>> also be too computationally heavy for an AP perhaps, at high speeds?
>>>>>> 
>>>>>> Immediate thought: this won't work for QUIC
>>>>> 
>>>>> .... as-is, true, though MASQUE is still being defined. Is this an
>>>>> argument for defining it accordingly?
>>>> 
>>>> MASQUE is proxying, right? Not quite sure if it's supposed to be also
>>>> MITM'ing the traffic?
>>> 
>>> Wellllll.... I'm not 100% sure. If I understood it correctly, ideas on the table would have it do this in case of tunneling TCP/IP over QUIC, but not in case of QUIC itself - but to me, this isn't necessarily good design?  Because:  =>
>>> 
>>> 
>>>> In any case, it would require clients to negotiate
>>>> a proxy session with the AP and trust it to do that properly?
>>> 
>>> => Yes.
>>> 
>>> 
>>>> This may
>>>> work for a managed setup in an enterprise, but do you really expect me
>>>> to be OK with any random access point in a coffee shop being a MITM?
>>> 
>>> MiTM is a harsh term for just being able to ACK on my behalf. Some
>>> capabilities could be defined, as long as they're indeed defined
>>> clearly. So I don't see why "yes, you can ACK my packets on my behalf
>>> when you get a LL-ACK from me" is MiTM'ing. I believe that things are
>>> now all being lumped together, which may be why the design may end up
>>> being too prohibitive.
>> 
>> Right, okay, but even setting aside the encryption issue, you're still
>> delegating something that has potentially quite a significant impact on
>> your application's performance to an AP that (judging by the sorry state
>> of things today) is 5-10 years out of date compared to the software
>> running on your own machine. Not sure that's such an attractive
>> proposition?
>
> Depends - this is what explicitly signaling this capability could solve.
>
> Take TCP, for example: if I'm all hyped on L4S, I may not want to
> delegate ACKing to an AP that doesn't support ACKing without support
> for accurate ECN signaling. If I do MPTCP and see support from the
> peer, then perhaps I don't want this capability at all. If I don't
> care about these two things... well, then, ACKing hasn't changed very
> much for several years. I may want to include some initial option
> information in that signal, for the AP to relay - e.g. about window
> scaling and such. I suspect that QUIC / MASQUE ACKing is also going to
> stabilize somewhat at some point in time.

Still a lot of complexity for something that (according to that TACK
paper) is only a marginal improvement over what can be achieved
end-to-end...

-Toke