[Bloat] [Make-wifi-fast] benefits of ack filtering

Juliusz Chroboczek jch at irif.fr
Sun Dec 3 14:53:32 EST 2017

> I can buy 300/10 megabit/s access from my cable provider.


> If I understand correctly, DOCSIS has ~1ms sending opportunities
> upstream. So sending more than 1kPPS of ACKs is meaningless, as these ACKs
> will just come back to back at wire-speed as the CMTS receives them from
> the modem in chunks. So instead, the cable modem just deletes all the
> sequential ACKs and doesn't even send these back-to-back ones.

If true -- then it's horrible.

> LTE works the same, it's also frequency divided and TDM, so I can see the
> same benefit there of culling sequential ACKs sitting there in the
> buffer. I don't know if this is done though.

I cannot find anything about Ack compression in LTE.  (The PDCP protocol
does header compression, so that's the place I'm looking.)

-- Juliusz

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