Example 2: Complex SRT Stream

This figure illustrates a more complex example, where an SRT source device behind a firewall is attempting to stream across the Internet to an SRT destination, also behind a firewall. If we consider the case where the SRT source device is in Caller mode, and the destination device is in Listener mode, then in order for the handshaking process described earlier to be successfully completed (and an SRT streaming session to be established) certain conditions must be met:

• The SRT source device must “know” the public IP address of the destination firewall, and port number on which the destination device is “listening”. This information usually comes from the IT Admin responsible for the firewall.
• Both firewalls must allow bi-directional UDP traffic.
• Port forwarding (NAT) must be configured on both firewalls to allow data to flow between the SRT source and destination devices.
• Packet filtering must be configured on both firewalls to allow the exchange of SRT packets between the source and destination devices.

Note

The order in which a firewall performs Network Address Translation and packet filtering will have an impact on how the packet filtering rules are configured.