3com DSA-3CV1001-02 User Manual

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PPENDIX

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ROUBLESHOOTING

The following table depicts normal counter indications and probable 
causes of abnormal counter indications.

The following provides a quick reference to problem identification by 
using frame counts:

There are two types of error messages that appear on the management 
terminal screen:

■

Advisory

Table 12   HDLC Traffic Count Indicators

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

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.