How does the router test the problem of the port?
The port does not connect the device and do the following operations:
1. Configure ip address 126.96.36.199 (188.8.131.52 is unusable address.) on the interface.
2. Under system view mode configure static arp: arp static 184.108.40.206 xxxx-xxxx-xxxx.
3. Configure loopback local on the interface.
4. Ping 220.127.116.11.
5. disp inter and check whether there is increase of statistics CRC. If there is increase of CRC, it indicates the port is not problematic.