Chapter 6
Troubleshooting
BERT Testing (Cisco 675, Cisco 675e and Cisco 676 only)
6-12
Cisco 600 Series Installation and Operation Guide
78-11190-01
Step 4
Initiate the BERT test:
cbos#
debug bert on
Step 5
Set the header bits of the outgoing cells and qualify the incoming cells.
Step 6
Enter:
cbos# debug bert header 00100010
Note
Note that these are the four bytes of header not including the
calculated HEC byte. Table 6-2 provides descriptions of the
bit fields.
Example: VPI=1, VCI=1 (GFC=0, PTI=0, CLP=0) across the ADSL loop (see
command line above).
Step 7
Display a count of the BERT errors and cell loss since the previous query:
cbos#
debug bert count
Step 8
Note that the two LEDs on the left of the CPE take on a new meaning during the
BERT tests.
•
BERT SYNC LED—This is the LED at the left (WAN-ACT) and is
illuminated once the PE detects a valid BERT pattern.
•
BERT ERROR LED—This is the second LED from the left (WAN-LNK) and
is toggled whenever the CPE detects a BERT error.
During a successful BERT test, the LED at the left will be illuminated, and the
second LED from the left will be solid (either off or on, but not blinking).
Table 6-2
BERT Header Bit Map
7
6
5
4
3
2
1
0
GFC
VPI
VPI
VCI
VCI
VCI
VCI
PTI
CLP
