Currently, the ME60 deployed on the carrier XX network uses the SBC function to bear the xPON voice service.
Detailed networking is shown as follows:
User―xPON―MAN--ME60 (SBC)--Bearer network--Softswitch and UMG
Softswitch and UMG in another city-User
Feedback from the xPON user is that many toll calls cannot be normally received. The symptom is that, after the ringing phone is picked up, the xPON user cannot hear any voice. Symptoms occur in about 50% toll calls, but do not occur in local calls.
1. Check the configurations of the ME60. The configurations are correct.
2. Check on the ME60 the route to the remote UMG. No route is found.
3. On the router on the local bearer network, check the route to the remote UMG. A correct route is learned.
4. The ME60 uses a new VPN connected to the bearer network. Check the VPN configuration of the router on the bearer network. The RT value indicating the intra-provincial media is not added to the new VPN. As a result, the ME60 cannot learn the route to the remote UMG.
5. On the router of the bearer network, add the RT value to the new VPN. After that, the intra-provincial toll calls become normal.
According to the service model, the problem is that the signaling flows can be normally transmitted, but the media flows fail to be forwarded normally. The local signaling service requires the communication between the ME60 and the local softswitch only, but the intra-provincial toll signaling service requires the communication between the local softswitch and the softswitch in another city as well.
The difference between the local media service and the intra-provincial toll media service is that the former requires the communication between the local UMG and the ME60, while the latter requires the communication with the UMG in another city (that is, the remote UMG).
According to the symptom, local calls are normal, which indicates that the ME60 can normally communicate with the local UMG. Successive intra-provincial toll calls are abnormal, which indicates that the ME60 cannot normally communicate with the remote UMG.
Based on the information from the core network that about 50% of the intra-provincial toll service volume is carried by the bearer network currently, the problem may be due to faults on the route between the ME60 and the remote UMG.
When dealing with faults related with the voice service, you need to fully consider the service process. Analysis of the signaling process and media process effectively helps you locate problems.