grr@cbmvax.UUCP (George Robbins) (03/10/88)
We have a single modest ethernet with a fair assortment of equipment
spread around the building. So far, network mangagment has been on
a plug-it-in-and-see-if-it-works-good basis. I'd like to be able to
so some monitoring with the following goals:
1) define ethernet loading and identify transceiver/interface level
malfunctions.
2) investigate problems with systems that won't talk to each other or
interfere with other conversations.
3) support development/debugging of in-house ethernet related hardware
software projects.
I've seen an ad for an Excelan 5100/5300 unit that seems to fit the
bill, but they want maybe $5K for it, which seems pretty expensive for
the amount of use it would get. I'd appreciate any comments about
this unit, good, bad or something else is better.
Also, is there any software, either 4.3 BSD or Sun related that could
be used to support this monitoring funciton, instead of going with a
piece of specialized equipment?
--
George Robbins - now working for, uucp: {uunet|ihnp4|rutgers}!cbmvax!grr
but no way officially representing arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)jeff@tc.fluke.COM (Jeff Stearns) (03/23/88)
In article <3447@cbmvax.UUCP>, grr@cbmvax.UUCP (George Robbins) writes
about his search for Ethernet test gear.
I'll put in a plug for the Cabletron LAN-MD. It's a suitcase-sized box that
can thoroughly test cables and transceivers. A pair of LAN-MD's can exercise
transceivers in place and tell you things that you'll never otherwise know.
Which of your transceivers have broken or out-of-spec collision detect
circuitry? How will you find them? Hint: Can a computer tell if its
transceiver has this problem?
Now that we're in the age of level I vs level II vs 802.3, we have abundant
opportunities to pair up Ethernet controllers with the wrong kind of
transceiver, multiplexor, or cable. Physical and link-level problems like
this are often inscrutable to higher-level tools.
Imagine a chart of the ISO reference model. Stick a pushpin in it for every
Ethernet problem you've had. Here's a starter drawn from recent memory:
Controllers that don't conform to the Ethernet spec, wrong cable type for
transceiver level, out-of-spec transceivers, defective transceivers,
broken Ethernet controllers, buggy controllers, buggy device drivers,
improperly-installed vampire taps, noise-sensitive transceivers, loose
transceiver cables, bugs in TCP/IP, NFS, ND, and ftp.
That puts a lot of pins down at the bottom of the chart, below the level of
monitors and protocol analyzers. The LAN-MD works well down there.
I wouldn't be surprised if Cabletron were working on something newer than
the LAN-MD; you might also want to ask 'em that.
--
Jeff Stearns
Domain: jeff@tc.fluke.COM
Voice: +1 206 356 5064
If you must: {uw-beaver,microsoft,sun}!fluke!jeff
USPS: John Fluke Mfg. Co. / P.O. Box C9090 / Everett WA 98206