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Ethernet Network or Hardware Error?

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The Question is:

I have one network containing two VAX 4000-50s, two DEC 90FA repeaters, and
 four DEC terminal server 200s.  One VAX, one repeater and two terminal servers
 are connected using thinwire on each side with fiber connecting the two
 repeaters.  I am using Centr
eCOM MX10 transceivers on each terminal server with SQE turned off.  This
 configuration is installed at three different sites, two of which are working
 great.  The third one is receiving periodic DecNet errors which end up causing
 all the terminal server
ports to logout (very annoying).  This error is received on the same computer
 (TVA2) each time and appears to be very random.  I have never seen it on the
 other computer.  The error logged is:
	DecNet TVA2
	DecNet 0.7 aborted service request
	From 1.42 (TVA2) 1-Sep-2003 00:35
	Circuit ISA-0 receive error
I have verified all my terminal servers are entered properly with the correct
 download file and the correct MOM$LOAD logical is defined.
Why would TVA2 be making a DecNet request from itself?
My NCP line counters are as follows:
Line = ISA-0
      >65534  Seconds since last zeroed
     2823773  Data blocks received
           0  Multicast blocks received
           4  Receive failure
   309952663  Bytes received
           0  Multicast bytes received
           0  Data overrun
     4367585  Data blocks sent
       45984  Multicast blocks sent
          96  Blocks sent, multiple collisions
         308  Blocks sent, single collision
        3547  Blocks sent, initially deferred
   363966106  Bytes sent
     2177768  Multicast bytes sent
           0  Send failure, including:
                Excessive collisions
      >65534  Collision detect check failure
           0  Unrecognized frame destination
           0  System buffer unavailable
           0  User buffer unavailable
One area of confusion Ive had is whether to enable or disable the SQE on the
 transceivers.  The heartbeat characteristic is disabled on all the terminal
 servers.  I seem to get about one collision detect check failure for each
 data block sent.  I ena
bled the SQE but that did not seem to make any difference so I set it back to
 disabled since it was working at the other sites with it disabled.
When I do a SHO DEV EZ, I have errors on EZA0.  Could this possibly indicate
 the Ethernet controller board has a problem?  The analyze utility did not show
 any entries for this device.
I am really pulling my hair out on this one  any ideas?

The Answer is :

  Please contact your hardware or network service organization for
  assistance in configuring and troubleshooting networking hardware.
  (This is not an OpenVMS error, this appears to be a network hardware
  or configuration error.)
  DECnet errors imply network cabling, hardware or termination errors,
  or packet corruptions.
  DECnet is not particularly related to LAT.
  There are massive numbers of collision detection failures here.
  While ancient Ethernet controllers -- those that predate IEEE 802.3
  -- do not require collision detection, typical IEEE 802.3 network
  controllers do.  (Typical ISA-class network controllers will expect
  collision detection, as well.)
  Please consider a supported hardware configuration, and particularly
  supported transcievers.  (For configuration and troubleshooting
  assistance with the particular third-party transceivers involved
  here, please contact the vendor directly.)
  Please contact your network or hardware service organization for
  further assistance with this configuration and troubleshooting.

answer written or last revised on ( 24-NOV-2003 )

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