[AusNOG] A question for carriers on autoneg

[Scott Howard]

On Sun, May 11, 2014 at 4:04 AM, Tim Warnock <timoid at timoid.org> wrote:

> Way back in the day(tm) some very popular Cisco devices were incapable of
> auto-negotiation.
>

Where "the day" was about the mid 1990's.  Last I looked, it was the mid
2010's. Unfortunately this whole issue has had a far longer memory than it
should ever have had.

Other reasons I've seen were that a lot of older carrier switches were
> incapable of policing ingress and egress and so the easiest way was to
> change the port speed.
>

Any worthwhile kit will allow you to independently control autoneg for
speed and autoneg for duplex.  Forcing a speed is generally not a problem,
it's only forcing duplex that causes any problems.

Of course, the better way to do this is to play with the capabilities
rather than the actual speed (so one end only announces 10Mbps, even if it
supports 100Mbps, etc), but not all hardware allows that.

  Scott
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