Subject: RE: Duration

From: Jerry Perser <[email-masked]>
Date: Mon, 21 Jun 1999 11:37:22 -0700

> At what point do people expect physical layer effects to 
> start interfering with test results?

Never.

One of Netcom Systems' European Customer is using our product because it
performed for 604,800 seconds with *ZERO* physical errors.  This was the
level of quality they required from the test equipment.  Each year, people
are requiring more performance at a better quality (go figure).  When Fast
Ethernet was just starting, people only required it to work overnight.  UNH
Lab looks for 10E-11 BER
(http://www.iol.unh.edu/testsuites/fe/tests/pmd/test25.2.4.html).

What your suggesting is that these new technologies can not run error free
for 30 seconds in a lab environment?  I disagree.  I have seen several 200+
port DUTs run 60 seconds with no physical errors (one of these was from
Nortel Networks).  I have also seen DUTs fail to forward a few frames out of
180 million frames.  We verified that the frames when into the DUT error
free but were never transmitted (per the DUTs statistics).

We can probably agree that if a test fails due to a "physical error" or
"clock tolerance", we can void the test with no penalty.  This must be
proven to be the cause.  Not an excuse for poor performance from an over
zealous marketeer.  This would be a manual intervention, where both the
Tester and the Testee can prove the error was not part of the inherent
design of the DUT/SUT.

---

From: "Steve Bell" <[email-masked]>
Date: Mon, 21 Jun 1999 13:12:08 -0700

Jerry,
What if we do the math, say 100 ports of GbE = 1e8 bps per port, x 1e2 ports
=  1e10 bps at a BER of 10e-11 = no errors??
Not to imply that the error distribution is strictly Gaussian, but it seems
that in the big tests you are likely to run
into this on a 30sec test, unless the BER is actually lower (quite possible)
.  Would make for an interesting side-test,
say when we do all of those 64-128 port GbE tests for Network World next
month...
-Steve
SVNL
www.svnl.com

----- Original Message -----
From: Jerry Perser <[email-masked]>
To: 'John Dawson' <[email-masked]>; bmwg
<[email-masked]>
Sent: Monday, June 21, 1999 11:37 AM
Subject: RE: Duration