James Carlson wrote:
[EMAIL PROTECTED] writes:Let me ask the question another way: by setting speed and duplex separately, is it actually possible to hit a permutation that would not happen with the predefined <speed>{f,h}dx definition?Yes. Half-duplex above 100Mbps gets pretty strange, and I suspect many (perhaps most) adapters don't support it. See 802.3-2002 section 4.1.2.1.1, 4.2.3.4, and 4.2.9. It's definitely a case of "so, remind me, just what problem was it you were solving .... ?"
The 10G spec finally did away with half duplex mode. 10GBaseT adapters will probably lack support for half-duplex even when negotiating for slower speeds (1G).
I _think_ most 1G copper adapters support half-duplex, at least when running at 100Mbps or slower.
Half duplex is useful for debugging (the ability to insert a hub in the middle), but a lot of 1G switches now (managed or web-managed) support port mirroring which can achieve the same thing without having to resort to half-duplex.
-- Garrett _______________________________________________ networking-discuss mailing list [email protected]
