Bridging
2-24 Bridge Statistics¥AlignmentÑThe number of frames received on a particular interface that
contain a nonintegral number of bytes (color-coded green). Misaligned
packets can result from a MAC layer packet formation problem, or from a
cabling problem that is corrupting or losing data.
¥FCSÑThe number of frames received on a particular interface that are an
integral number of bytes in length, but do not pass the FCS (Frame Check
Sequence) check.
FCS, or Frame Check Sequence, errors occur when packets are somehow
damaged in transit. When each packet is transmitted, the transmitting
interface computes a frame check sequence (FCS) value based on the contents
of the packet, and appends that value to the packet. The receiving interface
performs the same computation; if the FCS values differ, the packet is assumed
to have been corrupted and is counted as an FCS error.
¥SQE TestÑDisplays the number of times that the SQE Test Error message is
generated by the PLS sublayer on the selected interface.
The SQE (Signal Quality Error) Test tests the collision detect circuitry after each
transmission. If the SQE Test fails, a SQE Test Error is sent to the interface to
indicate that the collision detect circuitry is malfunctioning.
¥Carrier SenseÑDisplays the number of times that the carrier sense condition
was lost or never asserted when attempting to transmit a frame on a particular
interface.
Carrier sense describes the action an interface desiring to transmit will take to
listen to the communication channel to see if any other interface is
transmitting. If a Òcarrier is sensed,Ó the sensing interface will wait a random
length of time, and then attempt to transmit.
¥Frame Too LongÑDisplays the number of frames received on this interface
that exceed the maximum permitted frame size.
¥Internal MACÑThe number of frames that could not be received by the
interface due to an internal MAC sublayer receive error. These errors are only
counted if a Frame Too Long, Alignment, or FCS Error did not occur along
with the internal MAC error.
¥ Receive ErrorsÑDisplays the total number of receive errors of all types that
were detected by the selected interface while it was receiving a transmission.
Transmission Errors
Indicates the errors that occurred while the selected interface was attempting to
transmit frames. Possible transmission errors are:
¥DeferredÑ Displays the number of frames for which the Þrst transmission
attempt on this interface is delayed because the medium is busy.