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DECnet-Plus Excessive Collision OPCOM messages?

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The Question is:

 
Please explain this opcom message:
(Decnetplus)
 
Message from user SYSTEM on KABEL1
Event: Excessive Collision from: Node LOCAL:.KABEL1 CSMA-CD Station
CSMACD-0,
        at: 1999-05-11-11:58:30.821+02:00Iinf
        eventUid   D4AA00CA-0798-11D3-8A18-4B4142454C31
        entityUid  BCD353FF-071D-11D3-8002-AA000400953C
        streamUid  BFFFAC6D-071D-11D3-8004-AA000400953C
 

The Answer is :

 
  This may or may not indicate a problem with the network.
 
  A notification of an excessive collision simply means that when you
  transmit the packet, it repeatedly collides (upon retransmission) with
  network packet(s) being transmitted by other node(s).  Per the design
  of Ethernet and IEEE 802.3, the backoff before retransmission is supposed
  to be randomized at each station, to prevent lock-step retransmission
  errors when two nodes attempt packet transmissions in parallel -- but
  excessive network traffic, particularly with multiple stations active,
  can cause multiple collisions to arise.
 
  Check for an unterminated network connection (particularly if there are
  multiple controllers present in the system reporting the error), check
  for a temporarily or continually overloaded network, and other similar
  communications  transmission problems.  Also check for a "screaming"
  network controller on the LAN, or for a controller that is (erroneously)
  not listening before transmitting.
 
  Check the CSMA-CD counters to track the activity, in recent OpenVMS
  releases you can use the SDA command SHOW LAN/COUNTER, looking for
  the numbers of deferred and failed transmissions.
 

  

     

     
answer written or last revised on ( 20-MAY-1999 )
     
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