The MA5620E is connected to the softswitch of company Z through the H248 protocol and 16 voice users are connected to the MA5620E. In the test, only two calls are put through in each 16 calls and the busy tone is played for other 14 calls.
1. It is suspected that the busy tone is played because the network quality is poor. Ping the softswitch. No packet loss occurs and the delay is only 2�3 ms. This indicates that the network quality is good.
2. Perform mirroring packet capture and analyze the signaling. When the MA5620E is associated, if the ID of RTP added in the association is larger than 00001, the busy tone is played on the softswitch side. If the RTP ID is 00000 and 00001, calls can be made normally.
3. Check the softswitch. On the softswitch, only two RTP resources are configured for the MA5620E. The RTP adding mechanism in the MA5620E is: The RTP ID starts from 00000 and is added by one when a call is made. When the RTP ID increases to 00015, the RTP ID starts from 00000 again and this process repeats. Therefore, only two calls are put through in each 16 calls and the busy tone is played for other calls.
4. Add the RTP resources to 16 on the softswitch and then conduct tests. Calls can be made normally.
RTP resources of the softswitch of company Z are allocated in the static configuration mode. Therefore, before a device is interconnected to the softswitch, you should apply to the softswitch for sufficient RTP resources according to the model of the device.