User Manual

Dante Controller User Guide

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Advanced Routing: Using Multicast

Dante routing is unicast by default. This means that a separate flow is set up between each transmitter and

receiver. If several receivers are all subscribed to the same channels of a transmitter, it may sometimes be

more efficient to use

multicast

Multicast sends the same set of channels to multiple receivers. In practice, this usually means that the

audio flow is flooded throughout the network. If many receivers want the same channels, using multicast

can reduce overall network use, especially on the transmitter, because only one copy of each audio

channel needs to be sent, rather than many.

Dante receivers will automatically prefer multicast to unicast if it is available. This means that if a new

multicast flow is created containing the channels that a receiver is currently receiving as unicast, the

receiver will switch over to receiving audio from the multicast flow and the unicast flow will be removed.

Clock Synchronization

All Dante-enabled devices use the IEEE 1588 Precision Time Protocol (PTP) across the network to

synchronize their local clocks to a master clock, providing sample-accurate time alignment throughout the

network.

One Dante device will be elected as the PTP Master Clock for the network; all other Dante devices act as

a PTP Slave Clocks to the elected master clock. Although many Dante devices may be capable of

becoming PTP Master Clock, only one device will win the election. Devices with clock inputs (e.g. Word

Clock or AES3) will be preferred in the election process. A gigabit connected device is preferred over a

device connected via 100Mbps. A tie-breaker rule of the lowest MAC address is used if several equivalent

candidate master clocks are available. The election process may be overridden by manually setting

'Preferred Master' on a device.

Dante Clock Types

Each Dante hardware device can derive its clock from either its high-quality onboard clock circuit, or an

externally connected word clock. In the case of Dante Virtual Soundcard, the computer’s clock will be

used.

Clock Settings

Enable Sync To External

A Dante device set to 'Enable Sync To External' will use the external word clock from its host equipment to

tune its onboard VCXO. A Dante device with this attribute set will become the PTP Master Clock, unless

there is another Dante device present with 'Preferred Master' set.

Preferred Master

Sometimes it may be necessary to force a particular device to provide the PTP Master Clock. A Dante

device with 'Preferred Master' set will always be chosen as the PTP Master Clock. If more than one device

has 'Preferred Master' set, the device with the lowest MAC address will be chosen.

Note: If device A is deriving its clock from an external word clock source ('Enable Sync To

External'), but device B is set as Preferred Master, device A will lose sync with the Dante network