The networking was as follows: user-S8505-ME60.A user connected to the ME60 reported that the screen froze when playing the programs of CCTV9 (multicast address: 220.127.116.11). The users connected to a third-party BAS did not report such issues.
Huawei performed the following steps to identify the cause and resolve the issue:
1. Huawei connected a PC to the ME60 and found that freezing screen occurred when playing the programs of the specific channel.
2. Found that two multicast streams were sent from two ports (ports 8388 and 8316) at the multicast address of CCTV9.
Used the PC to redirect UDP traffic and found that the multicast stream from port 8316 was for CCTV9 and the other from port 8388 was for another channel. The stream rate was about 3 Mbit/s.
Used the multicast software to require video on demand (VOD) services using the original multicast address and port number and also found two multicast streams were available.
Continued to find that the video stream was higher than 3 Mbit/s when freezing screen occurred whereas the IPTV user was assigned up to 3 Mbit/s.Considering that the issue did not occur on an IPTV user connected to a third-party BAS, Huawei suspected that the rate limit function on the device did not accurately check the rate and perform corresponding actions.
1. The DSLAM connected to the ME60 was faulty.2. The multicast rate limit was too low.