[c-nsp] Re: autonegotiating hub was: Deferred packets on 2950 10/full interface

[John Neiberger]

>>> Mikael Abrahamsson <swmike at swm.pp.se> 1/16/05 12:33:58 AM >>>
>On Sat, 15 Jan 2005, Michael K. Smith wrote:
>
>> There is a Technology Ability Field bit that allows you to tell the
>> other side what you support vis-à-vis speed and duplex.  So, it is
>> possible to have a hub that can have the appropriate bit set to tell
the
>> other side that it supports 100TX, but not have a bit set for
supporting
>> 100-Full Duplex.
>
>This is what I want all vendors to support. If you set 100/f hard,
then
>keep the autoneg going but only announce ability to do 100/f. I see no

>reason to turn autoneg off just because you have fixed both duplex and

>speed? I haven't been able to aquire an answer to the rationale
vendors 
>have applied when opting to disable NWay when both duplex and speed is

>fixed?

I agree with you, and this is the way that Cisco's switches used to
behave. At least the switches that we used, anyway. We used to have a
bunch of 2924XL switches with all of the ports hard set. We first
noticed that things had changed when we replaced some 2924XLs with
2950-24s, which disable Nway when speed and duplex are fixed. This
caused a LOT of servers and desktops to freak out due to duplex
mismatches. Cisco's documentation at the time wasn't very helpful. I
opened up a documentation TAC case and successfully convinced them to
change their documentation a little bit. They're at least a little more
clear about the problem than they were before.

John
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