The Model 5401 Dante Master Clock was initially designed for use in applications that utilized devices running “native” Dante. To support the master timing needs of these devices Precision Time Protocol Version 1 (IEEE-1588-2002 or PTP v1) was implemented. The unit’s PTP v1 implementation functions very well, including in redundant Dante applications. (Independent Ethernet networks connected to the Primary and Secondary Ethernet ports on the back panel of the Model 5401.) Even in large installations with literally hundreds of Dante devices, correct performance has been confirmed.
However, the Model 5401 is more limited is its ability to support applications that require Precision Time Protocol Version 2 (IEEE-1588-2008 or PTP v2). The first limitation is that the unit is only capable of supporting AES67 devices that are connected to a single network. An Ethernet signal associated with that network would be connected only to the Model 5401’s Primary network port. No PTP v2 performance can be obtained with a connection made to the Model 5401’s Secondary network interface. A more significant limitation is that at the present time Studio Technologies does not have the ability to revise any of the PTP v2 operating parameters. This greatly limits the ability to use a Model 5401 as a general-purpose “grand master” for applications that need PTP v2. For example, SMPTE ST 2110-10 specifies SMPTE ST 2059-2 as its timing reference. An associated set of PTP v2 parameters (denoted as the “SMPTE profile”) is detailed in ST 2059-2. While certainly not optimal, the Model 5401 does not allow selection of a specific profile. It follows the configuration established by Audinate (developers of Dante) for supporting AES67 devices.
These PTP v2 parameters are “fixed” within the Model 5401 and cannot be changed:
Priority 1: 114
Clock Class: 248
Accuracy: Unknown (0xFE)
Priority 2: 112
Unique ID: 00:1D:C1:XX:XX:XX
DSCP: ER (46)
In conclusion, the Model 5401 Dante Master Clock can be a very effective product for the appropriate applications. But it’s not intended to serve as a general-purpose PTP v2 Grandmaster.