In a new office, the MA5600T is connected with an MA5606T that functions as an ONU. The H.248 interface on the MA5606T is normal; however, users connected to the MA5606T cannot hear the dial tone after offhook.
1. Check the parameters and the status of the H.248 interfaces. It is found that they are normal.
2. Check the data configuration of the user device. It is found that the data configuration is also normal.
3. Ping the softswitch consecutively from the MA5606T. It is found that 50% of the packets are lost.
4. Ping the softswitch consecutively from the MA5600T. It is also found that 50% of the packets are lost.
5. Check the upper-layer device, it is found that port aggregation is performed on the upper-layer device. The ports on the MA5600T, however, are not aggregated. Aggregate ports on the MA5600T. The fault is rectified, and the service is normal.
The main cause of the voice service problem is that the interconnection parameters of devices do not match. Therefore, the cause of this problem still lies in the interconnection parameters.
When the voice service fails, we pay little attention to the channel between the device and the softswitch if the H.248 interface is normal. This case tells us that the channel between devices is not surely normal although the H.248 interface is normal.