frozen netbsd-6-rc4

[6bone%6bone.informatik.uni-leipzig.de@localhost]

hello,

I am using netbsd-6-rc4 at a dell 1850. the server works only as router. 
it is connected with an lacp port-channel (4*1gb) to a cisco catalyst 
switch.

sometimes (1/day or more often) the system cpu usage increases to 300 
percent or more. in some cases netbsd is frozen (also the kernel 
debugger), in other cases netbsd continues to a normal work after some 
minutes.

The top command shows the following:

load averages:  0.76,  0.77,  0.58;               up 4+03:49:27       11:31:11
33 processes: 31 sleeping, 2 on CPU
CPU0 states:  6.2% user,  0.0% nice, 18.8% system, 11.2% interrupt, 63.9% idle
CPU1 states:  5.0% user,  0.0% nice, 12.8% system,  3.6% interrupt, 78.6% idle
Memory: 279M Act, 153M Inact, 6036K Wired, 20M Exec, 152M File, 296M Free
Swap: 4506M Total, 4506M Free

  PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU COMMAND
    0 root       0    0     0K 6928K CPU/1     13:37  0.00%   277% [system]
  464 root      43    0   316M  238M parked/0  21.4H 32.47% 32.47% named
  .....


Any idea what the problem could be? The hardware is ok and the switch 
does not show any abnormal network traffic.


Thank you for your efforts

Regards
Uwe