Secure Reliable Transport

Secure Reliable Transport has several distinct advantages:

1. Protect against jitter, packet loss and bandwidth fluctuation
2. Low Latency
3. End-to-end 128/256 bit AES encryption

Essentially, SRT wraps a UDP stream with the protocol to allow for more consistent streaming experience.

In Teradek Encoders, there are two modes.

• Server Mode (Pull or Listener Mode) allows clients to initiate a connection.
• Sender Mode (Caller Mode) video is sent to a destination.

Both modes have the following variables:

• Host (Server Mode Disabled) - Your destination IP or domain address.
• Port (Default 9710) - Port at which data is sent or pulled from. These ports must be open (outgoing or incoming) on your network for data to flow properly
• Passphrase - The key that is used to encrypt your stream.  Use this phrase in the decoder side as well.
• Encryption key size - Allows a preset selection of key size.  This variable must match at the receiving end.
• Latency (Default 500) - How much delay is in the stream.
• Adaptive Bitrate (Default Off) - Allows the encoder to adjust the bitrate dynamically if network conditions worsen.

Requirements for Network in Utilizing SRT (from SRT Alliance Guide)

• The SRT source device must “know” the public IP address of the firewall, and the port number on which the SRT destination device is “listening”.
• The firewall must allow the specific destination port used by SRT to be accessible from the Internet.
• The firewall must allow bi-directional UDP traffic.
• Port forwarding must be enabled on the firewall to allow data to flow to the IP address and port of the SRT destination device.
• Packet filtering must be disabled (to allow the SRT packets to pass through).