Dante Network Audio Technology

Dante makes use of "off-the-shelf" network equipment. The integrator should employ standard VoIP-style QoS in order to integrate Dante into existing network infrastructures alongside other applications. Dante uses standard Voice over IP (VoIP) Quality of Service (QoS) switch features, to prioritize clock sync and audio traffic over other network traffic. QoS is available in many inexpensive and easily obtainable Ethernet switches. Any switch that supports Diffserv (DSCP) QoS with strict priority and 4 queues, and has Gigabit ports for inter-switch connections should be appropriate for use with Dante.

The appropriate switch settings regarding QoS are as follows.

• QoS mode: Basic
• Trust mode: DSCP

Dante channel names can be up to 31 characters. When Cognio programs a channel name, it replaces any character other than a letter, number, space, hyphen (-), or underscore (_) with a hyphen, and shortens names longer than 31 characters.

Latency. is deterministic in Dante systems. That is, it is not dependent upon circumstance, but instead, well known and consistent within the system all of the time.

Each Dante receiver introduces a specific, user-adjustable amount of latency before playing out audio to account for any delay variation in the network or end device, and this guarantees that all devices play out in perfect sync. The Dante Controller sets this latency per device, and the value selected should be based on the size of the network. Some examples are shown below:

It is a "system-wide network latency setting". So, how much additional latency or skew is there for each switch hop? As it turns out the answer is none. As long as the (system-wide network) latency the user sets is long enough to cover all the switch hops, the packet will get to the end of the chain before the buffer expires. Then Dante uses its clock alignment mechanism (Precision Time Protocol) to exactly line up the outputs down to the sub-sample level. You can compare the word signals between any two Dante units and they should be accurate within 100 nanoseconds of each other, or less than 1% of a sample period (checked up to 10 units). So the outputs at multiple points in the network will all be sample aligned, each with the specified latency from the sender.

The receive latency set in Dante Controller is not additive, and it only needs to be long enough for a packet to traverse the entire network path. The only practical guide to give a user for this (beyond extensive network path and latency analysis using dedicated software) is the number of switch hops. Cognio does not set Dante latency.

There is a self-discovery "Plug and Play" process on the Dante network that will remember previously configured and Dante equipped units as they come into and out of the network. It is recommended that you use Gigabit switches when creating the Dante network. The latency setting is network wide and is not based on the number of units, or buses, but the number of switch hops. Cognio Smart Devices can receive Dante channels from any Dante-enabled third-party audio device.

A list of licensees of Dante technology can be found here:

https://www.audinate.com/meet-dante/dante-manufacturers-list

A list of third-party products that can pass audio to Cognio Smart Devices can be found here:

https://www.audinate.com/products/dante-enabled

In Cognio, you route Dante audio by patching modules in the Signal Flow view and by selecting receive channel sources for Managed Devices. When you push the Site, Cognio programs the Dante channel names and subscriptions of its Smart Devices and Managed Devices. Dante identifies each channel by its channel name and device name (channel@device). Dante digital audio is limited to the parameters of Ethernet technology and makes use of standard VoIP and QoS switch features.