...

dropwatch -l kas
>start

UDP socket buffers tuning on system level

If UDP is used to publish or play high bitrate streams (for instance, as CDN internal transport), UDP socket buffers tuning may be required

sudo sysctl -w net.core.rmem_max=26214400
sudo sysctl -w net.core.rmem_default=26214400

In this case the server performance should be enough to handle all the traffic packets. Otherwise, a translation quality will drop (a freezes will appear), and CPU will become a bottleneck.

Channel load optimization

...

[Service]
User=flashphoner
Group=flashphoner
LimitNOFILE=100000
...

Internal command to change file descriptors limit

Since build 5.2.1255 the following command can be used to set file descriptors limit:

sudo ./webcallserver set-fd-limit 100000

WCS will be stopped before settings changing and will be automatically started after settings changing to apply them.

If a new value is less than the default one (20000), erroe message will be displayed, and changes will not be applied.

Traffic encryption in a separate thread for each client session

...

rtp_paced_sender=true
rtp_paced_sender_initial_rate=200000
rtp_paced_sender_increase_interval=50
rtp_paced_sender_k_up=0.9

and restart WCS.

Stream distribution optimization

A stream playback quality may drop when a number of subscribers are viewing it simutlaneouly (from 100 and more): low FPS, freezes. However, server capacity and channel bandwidth may be enough. In this case it is recommended to enable multithreaded stream distribution to subscribers using the following parameter

streaming_distributor_subgroup_enabled=true

In this case, audio and video client sessions are distributed by groups.

Maximum number of video sessions per group can be set with the following parameter

streaming_distributor_subgroup_size=50

Maximum number of audio sessions per group can be set with the following parameter 

streaming_distributor_audio_subgroup_size=500

Frame queue size per group and maximum frame waiting time (in milliseconds) are set by the following parameters

streaming_distributor_subgroup_queue_size=300
streaming_distributor_subgroup_queue_max_waiting_time=5000

for video and

streaming_distributor_audio_subgroup_queue_size=300
streaming_distributor_audio_subgroup_queue_max_waiting_time=5000

for audio sessions respectively.