9 troubleshooting, 1 lapb is always disconnected, Fault description – Nortel Networks 8000 User Manual
Page 278: Fault analysis, Troubleshooting procedure, 2 lapb protocol is up, vc cannot be established, 9 troubleshooting -75, 1 lapb is always disconnected -75
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Nortel Secure Router 8000 Series
Configuration -WAN Access
7 LAPB and X.25 configuration
x25 x121-address 1002
x25 map ip 16.16.16.1 compressedtcp 16.16.16.1 x121-address 1001
ip address 16.16.16.2 255.255.0.0
#
7.9 Troubleshooting
This section provides troubleshooting methods for the following faults:
LAPB protocol is up, VC cannot be established
X.25 Protocol cannot enter the up status
X.25 Protocol is up, VC cannot be established
Frequently reset or cleared during data transmission
Request to set PVCs is rejected
After SVC application of XOT is configured, the ping fails
After PVC application of XOT is configured, the ping fails
7.9.1 LAPB is always disconnected
Fault description
Two connected sides are encapsulated with LAPB (or X.25); however, the protocol is always
disconnected.
Fault analysis
The possible cause is that the two ends are working in different modes.
Troubleshooting procedure
Do as follows on the routers:
Step 1
Enable the debugging. You can find that one end sends the SABM frame, and the other sends
the FRMR frame cyclically.
Step 2
Change the operation mode on one side to ensure the operation modes are consistent on both
ends.
—End
7.9.2 LAPB protocol is up, VC cannot be established
Fault description
The LAPB protocol is in the up state; however, the peers cannot ping through each other.
Issue 5.3 (30 March 2009)
Nortel Networks Inc.
7-75