Connection timed out

[Greg Barniskis]

Matthew Pope wrote:
> I find that during the blocking behaviour, when I try and ping the 
> windows box, a tcpdump shows that each second ping attempt is followed 
> by a response (it appears) from an IPv6 address...

> 13:30:51.066625 802.1d config 8000.00:30:19:53:05:00.8011 root 
> 8000.00:30:19:53:05:00 pathcost 0 age 0 max 20 hello 2 fdelay 15
> 13:30:53.069431 802.1d config 8000.00:30:19:53:05:00.8011 root 
> 8000.00:30:19:53:05:00 pathcost 0 age 0 max 20 hello 2 fdelay 15

If you're referring to the above samples as "appears from IPV6", 
those are Spanning Tree Protocol packets originating from the Cisco 
switch, and are unrelated to your ping test. You will see them on 
the wire frequently even in the absence of any normal IP traffic.

You probably want the following Cisco configuration directive added 
to those switch ports that do not connect the 2900 to other switches:

spanning-tree portfast

The presence of the STP packets may or may not be related to your 
performance issues. They shouldn't be, but some buggy NICs/drivers 
do seem to get freaked out by STP.

When STP is enabled on a switch port, it definitely will delay your 
initial link establishment by 30 seconds or so, when the attached 
computer is first powered up. That alone can confuse things when the 
NIC is trying to negotiate a link speed and the switch is still 
thinking about STP. It's even possible that you're getting a link 
speed/duplex mismatch out of it, and of course that will play holy 
hell with your response time.


-- 
Greg Barniskis, Computer Systems Integrator
South Central Library System (SCLS)
Library Interchange Network (LINK)
<gregb at scls.lib.wi.us>, (608) 266-6348