Getting Started with Dante: 7. Unicast and Multicast Transport

Published by Darron Toy on

In this video, we will explore two modes of audio transmission in
Dante: Unicast and Multicast. Understanding these modes will help you to get the best performance from
a large Dante installation. The terms Unicast and Multicast
refer to two different ways that network traffic can be sent to destinations. Unicast flows are one-to-one routes that deliver audio to and from specific devices, and support four channels of audio simultaneously. This is the default method used by Dante; however the number of Unicast flows is
limited. A configuration that sends the same audio to many destinations at one time
is called a “fanout.” The use of large fanouts may exhaust our supply of Unicast flows, as each identical transmission is
consuming network bandwidth. The solution to this problem is a
Multicast flow. A Multicast flow “broadcasts” the audio so that multiple receivers can subscribe,
but the transmitter is only using one of its available flows. If you subscribe multiple devices to the
same transmit channels via Unicast, Dante Controller may alert you with the
message “Fanout configuration detected” in the Event Log. This indicates that it’s a good idea to use Multicast for this transmission. Looking at this example, we can see that
this device is sending the same exact audio to 4 amplifiers, needlessly
consuming Unicast flows. To convert these transmitting channels to
Multicast, we open the Device view of the transmitting
device and click the Multicast button in the toolbar. This shows us all the transmitting
channels, and allows us to group any we select into a Multicast flow. We’ll
select the audio going to the main amplifiers. Note that Dante receivers adjust to
Unicast or Multicast automatically. Note that the flows now
have a Multicast icon beside them in the device view. Also note that the fanout warning is
gone, as we are now using only one flow to achieve what required four previously. You can delete Multicast flows from the
transmit tab of the device view, returning the device to Unicast operation. By offering both Unicast and Multicast modes, Dante is easily optimized for your particular environment. Be sure to watch the rest to the videos in
this series for more information.

1 Comment

Chris935 · August 15, 2019 at 5:55 pm

How many destinations should a transmitter be going to before it is optimal to switch it to multicast?

Leave a Reply

Your email address will not be published. Required fields are marked *