Cisco/BSD auto-negotiation

[Javier Henderson]

On Aug 21, 2006, at 9:11 AM, Dave Raven wrote:

> Hi all,
> 	I'm currently looking into a problem with a Cisco 3640 router and a
> FreeBSD 4.9 unit, connected via a crossover cable, that are not  
> negotiating
> correctly.
>
> If you force the media setting to full or half duplex it has constant
> collisions on the interface, and if you let both autonegotiate the  
> cisco
> keeps resetting (every ~20 seconds) its network card.
>
> Are there known issues with this, or any known fixes?

I've not seen this problem with my systems, all of which have Intel  
NIC's (fxp and em), they all correctly negotiate with the Cisco gear  
I've tested (a 2651XM and a few Catalyst switches running both IOS  
and CatOS). I've not seen the constant negotiation you report above.  
I've FreeBSD systems running 4.10-RELEASE, 5.5-RELEASE and 6.1- 
RELEASE, all up to date with security patches.

Note that if you force the FreeBSD system to a fixed setting, and  
leave the other side (your 3640 in this case) to auto negotiate, then  
the auto negotiating side will set itself to half duplex. However, if  
you set both to full duplex, then collisions should not occur.

I'd be interested at looking into this more, feel free to contact me  
off list to pursue this further.

Disclaimer: I work at Cisco.

-jav