H3C Technologies H3C SR8800 - Manual (Page 34)

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[RouterB-Pos3/1/1] fr dlci 70
[RouterB-Pos3/1/1] fr map ip 10.10.10.1 70
[RouterB-Pos3/1/1] mtu 1500
Follow the same way to configure Router C.
Check interface connectivity with the display interface pos command and test network connectivity with
the ping command.
Troubleshooting POS interfaces
Symptom 1
The physical state of POS interface is down.
Solution
• Check that the transmitting and receiving fibers-optic are correctly connected to the POS interface.
If you connect the two ends of a fiber-optic to the transmitting end and the receiving end of the same
POS interface, when you execute the display interface command, a “loopback detected” message
is displayed on the screen even if loopback is not enabled.
• If the two routers are directly connected back to back, check that the internal clock is enabled on
either of the two POS interfaces. POS interfaces use line clock by default. However, when two
routers are directly connected, one side must use the internal clock.
Symptom 2
The physical layer is up but the link is down.
Solution
Check the following items:
• The configurations of clock, scrambling and other physical parameters are consistent on the
connected two POS interfaces.
• The same link layer protocol is configured on two sides.
• Both ends are assigned IP addresses.
Symptom 3
A great amount of IP packets are dropped.
Solution
Check the following items:
• The correct clock mode is configured on the POS interface. If not, enormous amount of CRC errors
can be generated.
• The MTU configuration is appropriate.