bce packet loss

Doug Barton dougb at FreeBSD.org
Tue Jul 12 05:52:42 UTC 2011


On 07/11/2011 22:47, Charles Sprickman wrote:
> On Mon, 11 Jul 2011, Doug Barton wrote:
> 
>> On 07/11/2011 21:09, Charles Sprickman wrote:
>>> I've had it hammered into my brain over the years that for servers it's
>>> always best to set link speed and duplex manually at both ends to remove
>>> any possible issues with link negotiation.
>>
>> That hasn't been the right thing to do for at least 8 years or so,
>> probably 10 or more.
>>
>> Yes, back in the 90's when all of this stuff was still new it was not
>> uncommon to have autonegotiation issues, but any even sort of modern
>> hardware (on either side of the link) will do better with auto than not.
> 
> Some of us still work at places where the hardware is 10 years old, you
> know. :)

True ... hence my careful specification of "sort of modern." :)

> I do still see fixed setups in service provider handoffs - for example
> this colo, Level3 and Hurricane.  Also all our metro ethernet stuff
> specifies a fixed configuration.
> 
> From what I can gather, this seems to be the standard practice in that
> space, but then again you're supposed to be plugging into equipment that
> wouldn't have the buffer issues that a $450 Dell switch would have.

Well one could also say that this sort of thing tends to result from
the, "There is a knob, I MUST twist it!" syndrome.

> The rule I recall is never do autoneg on one side and fixed on the
> other, that more often than not will end up in a duplex mismatch.

Yes, that's definitely true, and I should have mentioned it. Whatever
you do on one side (auto/manual) you must also do on the other.


Doug

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