[Cerowrt-devel] [Make-wifi-fast] [tsvwg] Comments on draft-szigeti-tsvwg-ieee-802-11e

Michael Richardson mcr at sandelman.ca
Fri Jul 31 16:23:27 EDT 2015


Jonathan Morton <chromatix99 at gmail.com> wrote:
    >> I think that is achievable, *even if there is a WiFi network in the
    > middle*, by thinking about the fact that the shared airwaves in a WiFi
    > network behaves like a single link, so all the queues on individual
    > stations are really *one queue*, and that the optimal behavior of that
    > link will be achieved if there is at most one packet queued at a time.

    > I agree that queues should be kept short in general. However I don't
    > think single packet queues are achievable in the general case.

    > The general case includes Wi-Fi networks, whose TXOP overhead is so
    > ruinously heavy that sending single MTU sized packets is
    > inefficient. Aggregating multiple packets into one TXOP requires those
    > several packets to be present in the buffer at that moment.

Agreed... if one has a minimum of two queues (and *fq-codel has at least that
many), why isn't the naive method of:
       1) send everything from the low-latency queue
       2) send the other stuff until the TXOP is full

enough?  codel will keep the queues short.
The key thing I think, is that the markings (1)/(2) above be passed along
through all "subqueues"...






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