System information

Detailed Information on the show interfaces serial Command
Book Title
15-342
bytes output Total number of bytes, including data and MAC encapsulation, transmitted by the
system.
underruns Number of times that the transmitter has been running faster than the router can
handle. This might never be reported on some interfaces.
output errors Sum of all errors that prevented the final transmission of datagrams out of the
interface being examined. Note that this might not balance with the sum of the
enumerated output errors because some datagrams can have more than one error,
and others can have errors that do not fall into any of the specifically tabulated
categories.
collisions Number of messages retransmitted due to an Ethernet collision. This usually is
the result of an overextended LAN (Ethernet or transceiver cable too long, more
than two repeaters between stations, or too many cascaded multiport
transceivers). Some collisions are normal. However, if your collision rate climbs
to around 4% or 5%, you should consider verifying that there is no faulty
equipment on the segment and/or moving some existing stations to a new
segment. A packet that collides is counted only once in output packets.
interface resets Number of times an interface has been completely reset. This can happen if
packets queued for transmission were not sent within several seconds’ time. On a
serial line, this can be caused by a malfunctioning modem that is not supplying
the transmit clock signal, or by a cable problem. If the system notices that the
carrier detect line of a serial interface is up but the line protocol is down, it
periodically resets the interface in an effort to restart it. Interface resets can also
occur when an interface is looped back or shut down.
restarts Number of times the controller was restarted because of errors.
alarm indications, remote
alarms, rx LOF, rx LOS
Number of CSU/DSU alarms, and number of occurrences of receive loss of frame
and receive loss of signal.
BER inactive, NELR inactive,
FELR inactive
Status of G.703-E1 counters for bit error rate (BER) alarm, near-end loop remote
(NELR), and far-end loop remote (FELR). Note that you cannot set the NELR or
FELR.