Topology: NE80E――transmission device――transmission device――NE80E
There is much alarm of up/down at pos interface connecting NE80E device and transmission device. After the port is down, it is up within milliseconds. The port up/down causes the flap of the routing protocol and the whole network is not stable.
1. Collect log information of the device. There is much up/down information at NE80E device.
2. The network management receives much up/down information at NE80E device.
The solution is to import transmission alarm suppression. After the router receives transmission alarm suppression, the delay lasts several milliseconds. If the alarm lasts, it reports that the port is down and handles it later.
The configuration command of the device is as follows:
The configuration port is sensitive to transmission alarm
alarm lrdi sensitive
alarm pais sensitive
alarm prdi sensitive
The configuration port suppresses time for transmission alarm
carrier down-hold-time 50
The default alarm suppression time is 0ms.
After the configuration is finished, when the device receives transmission alarm, the port is not down within 50ms. If the alarm lasts over 50ms, the port is down.
The transmission device has AIS alarm of 2-5 milliseconds. The router will respond immediately when it receives AIS alarm. The port is down and then up. The routing protocol is re-established after it is interrupted. The route of the whole network flaps.