Symptom
When a user uses IP phone eSpace 7810 (extension number: 400) to make a call to XXXXX7893, the call can be set up, but neither the calling or called party can hear each other.
Version: U1910 V100R001C01SPC500
The following figure shows the network diagram.
![]()
Possible Cause
The network between the IP phone and the PBX is faulty.
Solution
Capture network packets and view the SIP call process.
![]()
The peer end returns the 200 OK message. The call is set up successfully.
![]()
According to RTP streams, IP address XXX.XXX.1.43 sends media information to IP address 10.200.200.243, but no response is received.
According to SDP messages, the media IP address used by the FastCo PBX is 10.200.200.243.
![]()
![]()
The IP address cannot be reached. As a result, neither the calling or called party can hear each other.
Add a static route on the router. The fault is rectified.Conclusion and Suggestion
The U1910 does not provide the media agent function. VoIP communication is based on IP point-to-point communication.
