SRT Connection Modes

In order to establish a connection, SRT employs a handshake mechanism where each device identifies itself as a Caller or as a Listener. In certain cases, two devices can simultaneously negotiate an SRT connection in Rendezvous mode. As you are configuring SRT streams, you should understand these handshaking modes and when to apply them:

Mode

What it does

When to use it

Caller

Sets a source or destination device as the initiator of an SRT connection. The Caller device must know the public IP address and port number of the Listener.

To initiate point-to-point streaming:

on a source or destination device that is behind a firewall; may require a network administrator to configure the firewall settings.
on a source or destination device that is not behind a firewall.
on a source or destination device with a dynamic IP address (e.g. a portable encoder using DHCP).

Example: Set a Makito X Encoder to Caller mode to connect to a Makito X Decoder over a private network, or vice versa.

Listener

Sets a device to wait for a request to open an SRT connection. The Listener device only needs to know that it should listen for SRT packets on a certain port.

To accept a point-to-point connection initiated by a Caller:

on a source or destination device that is behind a firewall over which you have control and can open a port.
on a source or destination device that is not behind a firewall, or exposed directly to the Internet.
when you know that another device will initiate the session.

Example: Set a Makito X Decoder to Listener mode to accept an SRT connection from a Makito X Encoder.

Rendezvous

Allows two devices to negotiate an SRT connection over a mutually agreed upon port. Both source and destination must be in Rendezvous mode.

To establish a point-to-point SRT connection when one or both devices are behind firewalls. Once certain settings are in place on the firewall, SRT connections can be initiated without further intervention by a network administrator.