Capture and analyze packets on the VMU.
1. Log in to the VMU as the user root
and run tcpdump -i any -s 1500 -w /home/XXX.cap host X.X.X.X -vvt
(x.x.x.x is the IP address of the FiberHome platform).
2. According to the captured packets, at 19:53:53, the FiberHome platform (172.21.239.173) requests live video playing, and the Huawei platform returns a 200 OK message.
3. At 19:53:57, the FiberHome platform requests video playback. The Huawei platform returns a 200 OK message. The following signaling does not contain the bye field. Normally, the code stream is not interrupted.
4. Check the media packets at this moment. It is found that the original live media port 19170 stops sending media streams. The port 19166 is used instead.
5. Compare the INVITE messages for live video playing and video playback. It is found that the sequence number of the receiving device in the Subject field of these INVITE messages are the same.
6. According to the T28181 standards, the sequence number of the receiver must be set to a different value.
7. The Huawei platform regards the live video playing and video playback requests as the same code stream. Therefore, the live video is stopped when the recorded video is played.
8. After the Subject field in the INVITE message is modified, the fault is rectified. The live video and recorded video can be played at the same time.