Network traffic flow between CDN servers through a private network¶

A signaling and media network traffic flows directly between CDN servers. The network interfaces to use will be chosen as follows if CDN servers are in private network:

CDN signaling messages passing via private network¶

If Origin and Edge nodes are in the same private network/VPC (or in the same cloud region and datacenter), and the Origin private address is set in Edge parameters, for example

# Edge external address
ip = 192.168.1.31
# Edge private address
ip_local = 172.16.0.31
...
cdn_ip = 172.16.0.31
cdn_role = edge
# Origin private address
cdn_point_of_entry = 172.16.0.1

then signaling traffic will flow via private network.

CDN media traffic passing via private network¶

Since build 5.2.2313 all the media traffic in CDN will pass through the interface set by cdn_ip parameter by default. So, all the traffic will pass via the private network in the example above. This means only cdn_ip address is added to the WebRTC candidates list when establishing a WebRTC connection between two CDN nodes.

The default behavior may be changed if necessary.

The parameter

rtc_ice_strict_cdn_interface=false

allows to add the address set by ip parameter to the WebRTC candidates list between CDN nodes. In this case media traffic may flow via private network or external network depending on ICE success.

The parameter

rtc_ice_add_cdn_interface=false

disables cdn_ip address to be used in the WebRTC candidates list between CDN nodes. In this case media traffic will flow via external network only.