FreeBSD 8.0 - network stack crashes?

[Weldon S Godfrey 3]

If memory serves me right, sometime around 10:43am, Weldon S Godfrey 3 told me:

>
>
> If memory serves me right, sometime around 3:13pm, Gavin Atkinson told me:
>
>> OK, at least we've figured out what is going wrong then.  As a
>> workaround to get the machine to stay up longer, you should be able to
>> set kern.ipc.nmbclusters=256000 in /boot/loader.conf -but hopefully we
>> can resolve this soon.
>>

I upped it to 256K.  What I am trying to wrap my head around is how it was 
working somewhat for so long at 24K, but it got to near 65K before I 
rebooted it with the higher setting.   Or did I reboot too early?  Is 
there any cleanup that isn't triggered intil it reaches max nmbclusters? 
I am trying to see if anything on our network has changed to cause this to 
become cronic.