H3C S9500 Series Operation Manual page 92

Operation Manual – Port
H3C S9500 Series Routing Switches
[SwitchB-Vlan-interface2] quit
[SwitchB] interface pos 3/1/1
[SwitchB-Pos3/1/1] pos access vlan 2
[SwitchB-Pos3/1/1] clock master
4.5 Troubleshooting POS Port Configuration
Symptom 1: The POS port is down at the physical layer.
Solution: Please check
Whether the optical fiber cables are connected correctly at the POS ports. There
should be two optical fiber cables, respectively stand for receive and transmit.
They cannot be connected inversely. If the Tx and Rx ends of a optical fiber cable
both are connected to the same POS port, then you can see the information
"loopback detected" when using the display interface pos command even if
loopback function is not enabled yet.
Whether the right optical module (providing POS ports) is inserted.
Symptom 2: The POS port has been enabled in the physical layer, but the link does not
report the Up state.
Solution: Please check
Whether inconsistent physical parameters, such as POS port clock, scrambling
setting, are set at both ends.
Whether inconsistent link data layer protocols are set at both ends.
Whether this or the peer end is not configured with an IP address.
Whether the port CRC settings are consistent at both ends.
Whether loopback is set on the port.
Whether the VLAN to which the port belongs has been deliberately disabled using
shutdown.
Symptom 3: Serious IP packet loss.
Solution: Possible causes include:
Incorrect clock configuration at the POS port (which has resulted in a large amount
of CRC error)
Inconsistent MTU (maximum transmission unit) configuration at both ends
Chapter 4 POS Port Configuration
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