76 A
PPENDIX
A: T
ROUBLESHOOTING
The following table depicts normal counter indications and probable
causes of abnormal counter indications.
Summary of
Abnormal Indications
from Traffic Counts
The following provides a quick reference to problem identification by
using frame counts:
Error Messages
There are two types of error messages that appear on the management
terminal screen:
■
Advisory
Table 12
HDLC Traffic Count Indicators
Counter Counts the Frames Normal Count
Abnormal count
indicates
Tx frames Sent via the
telephone line
High No transmit data
Rx frames Received via
telephone line
High No receive data
Tx discarded The VCN AP was
unable to send
Low VCN AP software
failure
Rx discarded The VCN AP was
unable to receive
Low, unless the
traffic is
bi-directional
VCN AP software
limitation
Overrun, Not
mine, DPLL
error, Abort
sequence, Non
aligned, CRC
error, Frame too
long
Containing Receive
fatal errors
Zero/low VCN AP hardware
failure if abnormal
count is growing
significantly by the
minute
Table 13
Summary of Problems Indicated by Counts of Errored Frames
Problem Solution
The following Ethernet traffic counters are
growing significantly: CRC error, Overrun,
Alignment error, Frame too long, or Frame too
short.
Replace in this order: the VCN AP,
or the Ethernet cable, or the PC
NIC.
The following HDLC traffic counters are
growing significantly: Tx error, Overrun, Not
mine, DPLL error, Abort sequence,
Nonaligned, CRC error, Frame too long.
Replace the VCN AP.
