Owner's manual

Port statistics shown via the show statistics command (Continued)TABLE 32
Parameter Description
Collisions The total number of packets received in which a Collision event was detected.
InErrors The total number of packets received that had Alignment errors or phy errors.
NOTE
Excessive errors for some counters usually indicate a problem. When you operate at a half-
duplex setting, some data link errors incrementing in Frame Check Sequence (FCS),
alignment, runts, and collision counters are normal. Generally, a one percent ratio of errors to
total traffic is acceptable for half-duplex connections. If the ratio of errors to input packets is
greater than two or three percent, performance degradation could be noticed.
In half-duplex environments, it is possible for both the switch and the connected device to
sense the wire and transmit at exactly the same time and result in a collision. Collisions may
cause runts, FCS, and alignment errors due to the frame not being completely copied to the
wire, resulting in fragmented frames. When you operate at full-duplex, errors in FCS, Cyclic
Redundancy Checks (CRC), Alignment, and runt counters must be minimal.
LateCollisions The total number of packets received in which a Collision event was detected, but for which a
receive error (Rx Error) event was not detected.
InGiantPkts The total number of packets for which all of the following was true:
• The data length was longer than the maximum allowable frame size.
• No Rx Error was detected.
NOTE
Packets are counted for this statistic regardless of whether the CRC is valid or invalid.
InShortPkts The total number of packets received for which all of the following was true:
• The data length was less than 64 bytes.
• No Rx Error was detected.
• No Collision or Late Collision was detected.
NOTE
Packets are counted for this statistic regardless of whether the CRC is valid or invalid.
InJabber The total number of packets received for which all of the following was true:
• The data length was longer than the maximum allowable frame size.
• No Rx Error was detected.
• The CRC was invalid.
InFlowCtrlPkts The total number of flow control packets received.
OutFlowCtrlPkts The total number of flow control packets transmitted.
Network Monitoring
FastIron Ethernet Switch Administration Guide 233
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