3Com DSA-3CV1001-02 service manual Summary Abnormal Indications From Traffic Counts

76APPENDIX A: TROUBLESHOOTING

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

Table 12 HDLC Traffic Count Indicators

			Abnormal count
Counter	Counts the Frames	Normal Count	indicates
Tx frames	Sent via the	High	No transmit data
	telephone line
Rx frames	Received via	High	No receive data
	telephone line
Tx discarded	The VCN AP was	Low	VCN AP software
	unable to send		failure
Rx discarded	The VCN AP was	Low, unless the	VCN AP software
	unable to receive	traffic is	limitation
		bi-directional
Overrun, Not	Containing Receive	Zero/low	VCN AP hardware
mine, DPLL	fatal errors		failure if abnormal
error, Abort			count is growing
sequence, Non			significantly by the
aligned, CRC			minute
error, Frame too
long

Summary of

Abnormal Indications

from Traffic Counts

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

Table 13 Summary of Problems Indicated by Counts of Errored Frames

Problem	Solution
The following Ethernet traffic counters are	Replace in this order: the VCN AP,
growing significantly: CRC error, Overrun,	or the Ethernet cable, or the PC
Alignment error, Frame too long, or Frame too	NIC.
short.
The following HDLC traffic counters are	Replace the VCN AP.
growing significantly: Tx error, Overrun, Not
mine, DPLL error, Abort sequence,
Nonaligned, CRC error, Frame too long.

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

■Advisory