1 Jan
2007
1 Jan
'07
9:31 a.m.
At 08:29 PM 12/31/2006 -0600, you wrote:
You wrote...
Yeah, I can
attest. We used to have one particular run of 3Com cards that
negotiated the wrong duplex about 25% of the time when used with one
particular kind of 10/100 blade in a Cisco Catalyst 5000 series switch. The
symptoms were that the connection would work ok, and ping tests seemed to
indicate all was well, but as you loaded the connection down a little, it
would start having errors and retries, until the retries overwhelmed any
real work being done.
Any time someone reported a good connection that would hang, timeout, and
quit with errors whenever you tried to copy a file over it (larger than a
few k) I know what the problem was.
A firmware upgrade fixed some of it. Policy fixed the rest: Thou shalt set
the speed and duplex we tell you to on your PC, or we'll disable your port.
No Auto/Auto permitted. Better gear and Corporate Standard NICs eliminated
the problem after a while.
[Computing] The use of COBOL cripples the mind; its teaching should,
therefore, be regarded as a criminal offence. --E.W.Dijkstra, 18th
June 1975.
--... ...-- -.. . -. ----. --.- --.- -...
tpeters at nospam.mixcom.com (remove "nospam") N9QQB (amateur radio)
"HEY YOU" (loud shouting) WEB ADDRESS http//www.mixweb.com/tpeters
43? 7' 17.2" N by 88? 6' 28.9" W, Elevation 815', Grid Square
EN53wc
WAN/LAN/Telcom Analyst, Tech Writer, MCP, CCNA, Registered Linux User 385531
Just trying to figure out why a 2 GHz box is
getting consistently
beaten by a 225 MHz one.
This sounds like the classic problem of a duplex mismatch between the
device and the hub. A lot of folks don't realize it, but when you mix
10mb/HDX/100mb/FDX devices in a single network - you would THINK that the
devices would autonegotiate identical settings on both ends. C'mon, they
even SAY they autonegotiate on the box, and they DO have an 'auto'
setting, right? Fact is, they get it wrong better than 80% of the time.
Even two devices from the same manufacturer usually don't autonegotiate
right. Pretend that "autonegotiation" doesn't exist. Set both ends
manually to identical settings. If one
Some will say - this can't be... I plug them in and they work, and the
right speed lights come on! And they pass traffic JUST fine. Don't trust
this. FDX/HDX mismatches can create very odd looking wierdness. Like a
connection that SEEMS to work, but is actually working very poorly.