Weird network connection problem

Robert G. Brown rgb at phy.duke.edu
Tue Oct 1 15:17:29 EDT 2002


On Tue, 1 Oct 2002, Yudong Tian wrote:

> They are all plugged into 8 identical Netgear 26-port stackable
> FSM 726 switches. The bad nodes are scattered on the 8 switches.
> I have also seen spooky cases with the bad nodes that some of them
> came back online automatically sometime around mid-night,
> stayed online for a few hours, then went offline again.

My netgear at home sometimes simply locks on certain ports (notably when
I reboot certain nodes).  I have to power cycle it to get it to rebuild
its tables.

That is, your problem could be some sort of pathology between the
netgears and your particular NICs, or it could be indicative of hardware
problems on those particular ports (marginal wiring, for example).

   rgb

> 
> 
> > What kind of switch are all the nodes plugged into?
> >
> >    rgb
> 
> 
> 
> > > Hi,
> > >    We've got 200 nodes running,  with each node having a
> > Biostar MB with a
> > > built-in Realtek 8192
> > > NIC chip, and running RH 7.2, 2.4-17. Recently we've seen a
> > weird problem
> > > with the
> > > network connection to some of these nodes. About 20 of them
> > will lose their
> > > network connections
> > > during the course of a few hours to a few days. And if I just unplug the
> > > network cable from
> > > such a node and plug it back in right away, the connection will
> > come back
> > > up.  Any insight
> > > where we should look for the problem: hardware? BIOS? Driver
> > module? Such a
> > > problem
> > > does not happen to any nodes randomly. It only occurs to those 20 or so
> > > particular nodes,
> > > which are identical to others except their MAC addrs.
> >
> > What kind of switch are all the nodes plugged into?
> >
> >    rgb
> >
> > Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
> > Duke University Dept. of Physics, Box 90305
> > Durham, N.C. 27708-0305
> > Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu
> >
> >
> 

Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu



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