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64−byte transmit time occurs. They are only
detected during transmissions of packets longer
than 64 bytes. Its detection is exactly the same as it
is for a normal collision; it just happens later than it
does for a normal collision.
Excessive
Collisions
Excessive collisions are the number of frames that
are dropped after 16 attempts to send the packet
resulted in 16 collisions.
Carrier
Sense
Carrier sense occurs every time an Ethernet
controller wants to send data and the counter is
incremented when there is an error in the process.
Runts These are frames smaller than 64 bytes with a bad
FCS value.
Giants These are frames that are greater than 1518 bytes
and have a bad FCS value.
Table 3Possible Causes for Incrementing CatOS Counters
Counter
Description
Alignment
Errors
These are the result of collisions at half−duplex,
duplex mismatch, bad hardware (NIC, cable, or
port), or a connected device that generates frames
that do not end with on an octet and have a bad
FCS.
FCS
These are the result of collisions at half−duplex,
duplex mismatch, bad hardware (NIC, cable, or
port), or a connected device that generates frames
with bad FCS.
Xmit−Err
This is an indication of excessive input rates of
traffic. This is also an indication that the transmit
buffer is full. The counter must only increment in
situations in which the switch is unable to forward
out the port at a desired rate. Situations such as
excessive collisions and 10 Mb ports cause the
transmit buffer to become full. If you increase
speed and move the link partner to full−duplex, it
minimizes this occurrence.
Rcv−Err
This is an indication of excessive output rates of
traffic. This is also an indication that the receive
buffer is full. This counter must be zero unless
there is excessive traffic through the switch. In
some switches, the Out−Lost counter has a direct
correlation to the Rcv−Err.
UnderSize This is an indication of a bad frame generated by
the connected device.
Single
Collisions This is an indication of a half−duplex
configuration.