3Com DSA-3CV1100-02 service manual Hdlc Traffic Count Indicators

128TROUBLESHOOTING

Table 17 Ethernet Traffic Counters (continued)

Counter	Counts the Frames	Normal Count	Abnormal Count
			Indicates
CRC error,	Containing receive	Zero	Hardware failure:
overrun,	errors.		VCN AC port,
Alignment			Ethernet cable or
error, frame too			Ethernet switch
long, frame too
short

HDLC Traffic Counters The normal frame counters indicate HDLC traffic counters between the CPE and the VCN AC. Some errored frame counters indicate fatal errors, requiring replacement of the VCN AC, or handling of environmental noise over the line.

Table 18 presents normal counter indications and probable causes of abnormal counter indications.

Table 18 HDLC Traffic Count Indicators

Counter	Counts the Frames	Normal Count	Abnormal 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 AC was	Low	VCN AC software
	unable to send		limitation
Rx discarded	The VCN AC (CO)	Low, unless the	VCN AC software
	was unable to receive	traffic is	limitation
		bi-directional
Overrun, Not	Containing Receive	Low	VCN AC hardware
mine, DPLL error	errors		failure if the number of
Abort sequence,			errors is growing.
Non aligned,
CRC error,
Frame too long