Steven Stallion writes: > Garrett D'Amore wrote: > > en_xxx set the bits used in 802.3u (MII) configuration. Directly > > setting the duplex and speed properties would be a subset of > > functionality. (Because using the en_xxx bits, you can offer to support > > more than a single configuration ... e.g. you could offer to support 100 > > FDX *and* 10 FDX.) > > Okay, so lets say that en_10fdx_cap and en_100hdx_cap are set; does this > affect negotiation? Is there a heuristic for choosing the correct cap?
It's a strict priority defined by 802.3 section 28.2.3.3 and Annex 28B.3. It has to be -- otherwise, there'd be no hope of interoperability when a pair of systems have two or more modes in common. For those two, 100Mbps half-duplex has higher priority than 10Mbps full-duplex. In general, it's speed first, then duplex. As for "why," this is much better than bluntly disabling autonegotiation. With autonegotiation disabled on just one side of the link (the common installation error case), the partner is forced to fall back to its lowest setting (10Mbps half-duplex), and nothing works. Better still, of course, is not to touch the fiddlin' bits. ;-} -- James Carlson, Solaris Networking <[EMAIL PROTECTED]> Sun Microsystems / 35 Network Drive 71.232W Vox +1 781 442 2084 MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677 _______________________________________________ networking-discuss mailing list [email protected]
