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Is avoiding a collision always preferable? CSMA/CA has significant overhead (backoff period) for every single frame sent, on a less congested line CSMA/CD has less overhead.

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But CSMA/CD also has a backoff period.

CSMA/CD only requires that you back off if there actually is a collision. CSMA/CA additionally requires that for every frame sent, after sensing the medium as clear, that you wait for a random amount of time before sending it to avoid collisions. If the medium is frequently clear, CA will still have the overhead of this initial wait where CD will not.

Depending upon how it's actually implemented, CSMA/CA may have the same (untended?) behavior of CSMA/CD in the sense that setting TCP_NODELAY will also set the backoff timer to zero. It would be interesting to test.

(My other post in this thread mentions it.) https://news.ycombinator.com/item?id=46360209#46361580

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