Nortel Networks 8000 - Manual (Page 95)

4 POS and CPOS interface configuration
Nortel Secure Router 8000 Series
Configuration -WAN Access
interface Serial3/0/1/1:0
link-protocol ppp
ppp mp Mp-group 0/0/3
#
interface Serial3/0/1/2:0
link-protocol ppp
ppp mp Mp-group 0/0/3
#
interface Serial3/0/1/3:0
link-protocol ppp
ppp mp Mp-group 0/0/3
#
interface Serial3/0/1/4:0
link-protocol ppp
ppp mp Mp-group 0/0/3
#
interface Mp-group0/0/3
hic-bind enable
#
return
4.8 Troubleshooting
This section provides troubleshooting methods for the following faults:
• Physical status of POS interfaces is Down
• Line protocol status of POS interfaces is Down
• Severe packet loss on a POS interface
4.8.1 Physical status of POS interfaces is Down
Fault description
After configuring the POS interface of the routers, use the display interface pos command to
view the interface status and find that the physical layer status of the POS interface is Down.
Fault analysis
The possible causes are:
• The fiber connected to the POS interface is incorrectly connected.
• The clock mode configured on the router does not match that on the peer device.
Troubleshooting procedure
Do as follows on the routers:
Step 1 Check if the fiber correctly connects to the POS interface. There are two fibers, which are
respectively used for receiving and sending and cannot be plugged inversely. In addition, if
the receiving end and sending end connect to the same POS interface, even when the
loopback is not enabled, the message of "Loopback detected" still can be found when you use
the display interface command.
4-34 Nortel Networks Inc. Issue 5.3 (30 March 2009)