sek@sabre.bellcore.com (Spencer Kantor) (07/20/89)
We have an old Sun 3/160 server that's running 3.2 and supporting 8 diskless 3/50's. Over the last couple of weeks we've been getting a frequent "ie0: No carrier" message printed to the console. Despite the frequency of the message (several times per hour) the system appears to be running fine. All cable connections are solid, network services are running fine (as far as we can tell) and there have been no complaints from the owners of the diskless clients about service interruptions. We'd like to know what causes generation of this message and what corrective actions may be warranted. Thanks.
menges@menges.cs.unc.edu (John Menges) (07/28/89)
In our experience (with Siecor's fiber-optic ethernet, especially the
passive one) this is usually caused by collisions which for some reason go
undetected or are not reported to the Sun properly. I suspect what's
happenning is that the Sun ethernet hardware is monitoring the signal it's
transmitting (on its receive pair) to make sure it conforms to the
manchester encoding rules. If it doesn't, and no collision is reported,
it reports that it has lost carrier. Under older Sun operating systems,
the output errors column of "netstat -i" incremented each time a "no
carrier" message was printed. Later versions of the operating system
didn't report "no carrier" messages each time the event occurred. I
suspect Sun got tired of hearing complaints and changed the system so it
only reported some of the errors (e.g., only if they happen twice in a row
or some such).
There are various problems that can cause "no carrier" messages (actually,
you should monitor output errors instead, as this is now more reliable).
Our biggest contributor was the passive fiber system. It doesn't work
because collisions are not detected reliably. The fiber ethernet system
vendors now recognize this and have switched to active stars. Other
contributors are faulty transceivers and transceiver cables that are too
long (50 Meters is really the limit). You might also have a faulty
tranceiver cable, or the Sun ethernet card might be defective. We have
eliminated nearly all output errors from our system of about 100 Suns,
except for the Sun-4s, which report output errors no matter what we do.
By the way, lots of output errors can make your nfd daemons hang. Watch
out for this.
The problem was so big here with the passive stars that the grad students,
when voting for the year's departmental T-shirt, chose:
ie: no carrier
ie: no carrier
ie: no carrier
ie: no carrier
ie: no carrier
ie: no carrier
I have some shell scripts that collect netstat statistics from all our
suns twice a day, and generate reports sorted on various fields (e.g.,
output errors, descending). This helped us to know where our worst
problems were, and we attacked them first. Let me know if you want the
scripts.todds@uunet.uu.net (Todd Sandor (2704)) (08/13/89)
In article <319@brazos.Rice.edu> sek@sabre.bellcore.com (Spencer Kantor) writes: >X-Sun-Spots-Digest: Volume 8, Issue 80, message 4 of 15 >frequent "ie0: No carrier" message printed to the console. Despite the We were experiencing these problems for a while and then converted the ethernet connectors (clip ons) with a rs232 screw in type, the problem went away after this. Its just a loose connection even though the clip-on type may seem secure. The AMP part numbers are: 1-745172-3 (goes on the end of the cable) 205817-1 (goes on the host side, replaces the clip) This should solve the problem, it did for use as well these cable never fall off anymore. -- Todd Sandor Voice: (613) 738-1338 ext 2704 P.O. Box 9707 Cognos Incorporated FAX: (613) 738-0002 3755 Riverside Dr. uucp: todds@cognos || uunet!mitel!scs!cognos!todds Ottawa, Ontario,Canada K1G 3Z4 Worlds may change, galaxies disintegrate, but a woman always remains a woman. <st>