Re: [Bloat] emulating non-duplex media in linux qdiscs

[Michael Richardson <mcr+ietf@sandelman.ca>]

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<erik.taraldsen@telenor.com> wrote:
    >> Saying that is half duplex, doesn't work for me. In their example of
    >> "half duplex", (using push to talk), it still means that everybody on
    >> that channel hears who is talking. "half duplex" to me, given the
    >> definition of duplex, means more that there is a *p2p* channel (a wire),
    >> that you can ping pong data across.

    > Well, as Mikael stated as well, half duplex has been used on shared
    > medium in the ethernet world since it's inception.  As you state it
    > does not match 100% with the wikipedia definition, but the tradition is
    > there.

The ethernet interface on the device is half-duplex, because it can only do tx
or rx to/from the coax cable.  There is in essence a half-duplex connection
there. (And with thickernet, there was actually a p2p AUI cable...)

But, the coax cable is *not* half-duplex, because it has more than two
senders to multiplex, so it can't be "half" duplex.
And it's the coax that we actually want to similate, not the AUI cable.

    > Given your distaste for the term half duplex, and the coming advances
    > in .11ax which further confuses the issue, there may be a real need for
    > a better term.  How about starting with a description of the
    > transmission properties and making a set of terms?  Shared medium,
    > single sender, multiple recivers. (current mu-mimo wifi).  Shared
    > medium multiple sender, multiple receivers. (OFDMA 802.11ax if they get
    > it working).  Shared medium entails coordinated action.
    > Sender/receiver description also encapsulates that there is different
    > behavior in the different direction in the air.

semi-multiplex

--
Michael Richardson <mcr+IETF@sandelman.ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-




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