Updated 21-Dec-2020
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 in its ability to support applications that require Precision Time Protocol Version 2 (IEEE-1588-2008 or “PTP v2”). This would include support for AES67 and ST 2110 devices. A significant Model 5401 PTP v2 limitation is that Studio Technologies does not have the ability to revise any of the PTP v2 operating parameters. This greatly restricts the ability to use a Model 5401 as a general-purpose PTP v2 Grandmaster. 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 the technical standard for ST 2059-2. Unfortunately, the Model 5401 does not allow selection of a specific profile. It has to follow the configuration originally established by Audinate (developers of Dante) for supporting AES67 devices.
These PTP v2 parameters are “fixed” within the Model 5401 and cannot be changed:
Domain 0
Priority 1: 114
Clock Class: 248
Accuracy: Unknown (0xFE)
Variance: 61536
Priority 2: 112
Unique ID: 00:1D:C1:XX:XX:XX
DSCP: ER (46)
While that can be an issue, on the positive side, as with PTP v1, independent PTP v2 performance will be provided on the Model 5401’s Primary and Secondary Ethernet ports. So redundant or “dual stream” performance should be possible.
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. Will it work in many cases? Absolutely. But careful testing will be required to ensure that the desired PTP v2 performance will be provided.
Model 5401 Dante Master Clock Front View