SUN networking problems - test-drb@ccmp.vtda.org

25 Mar 2001

On Mar 26,  7:28, Arno Kletzander wrote:

...
  Hi folks, we powered up the working pizza box and the
laser this weekend. At
...
  first we got a lot of
 le0: no carrier - transceiver cable problem?
 style errors during bootup and in the console window, but they disappeared
...
  when we re-seated the AUI cable on the SUN.
Unfortunately, that was not all of
...
  the problem. If you now try to print to pa3 (which is
the CalComp?s name),
...
  the job is stored in the printer queue, but there also
appear a number of
 error messages "No answer from host pa3 on parallel port" when you LPQ
for it.
...
  PINGing for the printer ends up with "no answer
from pa3".
 Is the SUN trying to send the data to a parallel-port printer although the
...
  CalComp is on the Ethernet? 
Maybe.  Have you tried pinging the printer by it's IP address instead of
it's name?  Try a broadcast ping?  Have you checked the printer settings to
make sure it's using the correct IP address?  Is that set from its panel,
or by RARP/BOOTP/DHCP?  If the latter, it needs a server to boot.  If the
Sun didn't get a valid signal from the transceiver when it booted, it might
not have enabled le0, or there might not be a route through it.  Check with
"netstat -rn" and "ifconfig le0".

...
  Peter Turnbull wrote:
 >Do those transceivers have a set of LEDs on them? I suspect not, but that
...
  might tell you
if anything is being transmitted/received. 
 On the transceiver connected to the SUN, the PWR (green) and SQE (yellow)
 LED are alight as long as the system is powered up. 
That's how it should be.  However, if there is an LED for either transmit
or receive, it should flash when you try a ping.  If it doesn't, either the
Sun isn't sending the packet or there's a short circuit.

...
  The only (green) LED on the
 printer?s transceiver is also on as long as the printer is. 
That probably just means it has power.

...
  If I connect the printer to one of the 3-LED
transceivers, the PWR LED is on
...
  all the time and the other two give very short flashes
when the printer has
...
  completed its warming-up cycle and is in ready mode.

Both LEDs?  I'm guessing as to what the LEDs do, but that probably means
it's transmitting something.  Maybe an ARP or BOOTP request.  It depends on
what the LEDs do.  One might be for collision, in which case there's a
cable fault if it flashes.  More likely one is transmit and the other
receive, in which case what you see is correct, it transmits a packet and
simultaneously detects what it's transmitting.

...
  There are also three LEDs on the back side of the
printer next to the AUI
 connector; two of them (green and orange) illuminate during the warming-up
...
  phase, then the orange one goes out and the green one
begins to flash.
 I have not noticed any flickering etc. of LEDs when trying to print or ping.

Hmm...  What are the LEDs on the transceivers labelled?  Mine have 5 LEDs:
Power, SQE, Transmit, Receive, and Collision. (I also have several
transceivers with no LEDs, or just one for power, but none with three.)

...
  Tony Duell wrote:
 >How hard is it to swap over the transceiver cables between the 2 Suns? If
...
  >it then works, you know the problem is either the
transceiver that used to
...
  >be connected to the working sum, or a nasty
problem caused by reflections >on
...
  the cable 
Not necessarily, it might not have brought up the le0 interface if the AUI
cable was disconnected when it powered up.

...
  on the cable, the band is:
 -in one case, inside the tap block
 -in two cases 1 and 2cm out of it (which means ca. 6cm away from the core
 contactor pin).
 We placed the new one also in such a way that the band is now inside the tap
...
  and not visible from the outside. 
Sounds like two of the original tranceivers are slighly off position
according to the specification, but on a relatively short cable with only a
few transceivers, I doubt a small deviation matters very much.

...
  How about the distance terminator to first tap? I
measured here about 1.25
...
  meters, which would be half the tap-to-tap distance.
As I don?t know much
 about signal transmission in Coaxes, does this make as much sense as it seems to?

The distance to the terminators doesn't matter, it doesn't have to be any
particular distance.

-- 

Pete						Peter Turnbull
						Network Manager
						Dept. of Computer Science
						University of York