3Com LINKBUILDER 3C18500 User Manual page 201

Late Events . A Late Event is an out of window collision, which may
occur if you have an 802.3 LAN that exceeds the maximum size as
defined by IEEE. A Late Event is also counted as a collision.
Multicast Frames . This is the total number of multicast frames seen
at the repeater, module or port. A multicast frame is one that is
addressed to a group of MAC addresses (that is, several devices) on
the network. The total number of multicast frames will normally be
a small percentage of the value seen for unicast frames.
A high level of multicast frames can adversely affect network
performance.
Runt Frames . Runt frames are frames that are smaller than the
minimum frame size defined for 802.3 frames, but longer than Short
Events. Runt frames may occur as the result of collisions, and will be
propagated around the network. This is a normal part of CSMA/CD
operation and is not an error.
Short Events . Short Events are smaller than runt frames and are
errors. They may indicate externally generated noise causing
problems on the network.
Check the cable routing and re-route any cabling which may be
affected by external noise sources.
Too Long Frames . Too Long Frames are frames that exceed the
maximum size for 802.3 frames (1518 octets).
If you see a high number of such frames you will need to isolate the
source of these frames and examine the transceiver or adapter card
at the device. However, some network protocols cause these frames.
Total Collisions . Collisions are a normal part of 802.3 operation and
occur if two devices attempt to transmit at the same time.
A sudden sustained increase in the number of collisions may
indicate a problem with a device or cabling on the network,
particularly if this is not accompanied by a general increase in
traffic.
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