[K12OSN] Network Error Troubles Again ...

[Steve Wright]

On Mon, 2004-03-08 at 06:23, Jim Christiansen wrote:
> I know I'm shooting in the dark but my school needs some new ideas again :-)
> 
> My son is doing a Science Fair Project on clustered computers and has 
> everything functioning just fine and looks like he may make it to the 
> nationals with his angle using open mosix.
> 
> He wanted to run a series of seti jobs on one of my labs that is k12ltsp 
> based but using a bunch of knoppix-cluster cds to come up with some really 
> impressive numbers (and for the fun of it).
> 
> What he discovered was that of 14 network drops, only three consistently 
> returned errors:0 dropped:0.  All of the others after running for only a 
> minute or so were ifconfiging errors:25 dropped:150 or worse.  This is on 
> the exact same machines that work steadily through every school day as 
> k12ltsp clients w-i-t-h one or two random freeze-ups each day.
> 
> Our technician has been in the school recently and has added a couple new 
> long runs to switches 300 feet away from the main gear in our network.  I 
> don't think that a network tester was used to check the new runs...
> 
> Is it possible that these errors be caused by new but faulty distant network 
> runs? Or, is this a problem that is more likely local to a bad switch the 
> library boxes are hooked to?
> 
> Please feel free to bring out the crystal balls for this one!

/me brings out crystal ball, polishes it.. The answer is...  YES!

IMO, it is perfectly feasible that these network cables are shonky.
Technically, 100MBit/sec is a huge data rate for a simple unshielded
twisted pair cable (nearly 1 GHz of RF bandwidth), and up until 10-15
years ago it simply was not done.  One slight flaw in anything is gonna
hiccup it, or worse.

/steve