DDM: Synchronous Clocking
All Dante devices in a given domain lock directly or indirectly to one single Grand Leader clock device.
In the case of domains for which all devices reside on the same IP subnet, the standard Dante method of multicast PTP clocking is used. One clock Leader device is automatically elected or manually specified, which broadcasts the clock signal via multicast PTP, and all other devices follow their own clocks to that Leader device.
In the case of domains that span subnets, one Grand Leader clock device is automatically elected (or manually specified) for the domain, and one boundary clock device will be automatically elected for each subnet (identified as the ‘unicast clocking’ device in the DDM clocking settings). Usually, the Grand Leader will also act as the unicast Leader for its own subnet.
The Grand Leader transmits the PTP clock signal via multicast to the follower devices in its own subnet, as is the case for traditional Dante networks. The elected unicast clock in the Grand Leader’s subnet transmits the clock signal via unicast PTP, through the router, to the unicast clock in the adjoining subnet, which in turn transmits multicast PTP to the other devices in that subnet.
The same model applies to any other subnets in the domain. This system enables synchronous Dante networks that span multiple subnets.