Brainstorm Electronics DXD-8 User manual

DXD8/PTP
PTP Firmware option for the DXD-8 Universal Clock
Operations manual
Version 2.15
October 2021
All materials herein © Brainstorm Electronics, Inc.
Brainstorm Electronics reserves the right to change or modify the contents of this manual at any time.
Brainstorm Electronics, Inc.
www.brainstormtime.com

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DXD8/PTP User Manual (rev 2.15)
1. Introduction!4...............................................................................................................................
2. Installation!4................................................................................................................................
3. Reference & Sync Menus!5...........................................................................................................
3.1 REFERENCE MENU (MENU 1.1)!5.............................................................................
3.2 SYNC PARAMETERS (MENU 1.2)!5............................................................................
4. PTP Menus!5................................................................................................................................
4.1 PORT MODE (MENU 5.1)!5.......................................................................................
4.2 PTP - CLOCK / GRANDMASTER (MENU 5.2)!6..........................................................
4.3 PORT CONTROLS (MENU 5.3)!6...............................................................................
4.4 PORT TIMING (MENU 5.4)!7....................................................................................
5. Time of Day!7..............................................................................................................................
5.1 RTC (Real Time Clock)!8..................................................................................................
5.2 Time Jam!8....................................................................................................................
5.2.1 TIME JAM TO PTP!8................................................................................................
5.2.2 What is the sequence of a complete Time Jam to PTP?!8...........................................
5.2.3 What is required for a Time Jam to PTP?!9...............................................................
6. Time Menus!9..............................................................................................................................
6.1 TIME STANDARDS (MENU 7.1)!9...............................................................................
6.2 TIME & DATE DISPLAY (MENU 7.3)!9.........................................................................
7. Time Code Menus!9......................................................................................................................
7.1 SMPTE 2059 SETUP (MENU 8.1)!9.............................................................................
7.2 LTC GENERATOR 1 & 2 (MENUs 8.2 & 8.3)!10...........................................................
8. Display!10...................................................................................................................................
8.1 Main Rotation!10............................................................................................................
8.1.1 MAIN ROTATION FOOTER!10.................................................................................
8.1.2 MAIN ROTATION PAGES!10...................................................................................
8.2 Status Pages!11..............................................................................................................
8.2.1 TIMES STATUS PAGE!11..........................................................................................
8.2.2 GRANDMASTER ID PAGE!11..................................................................................
9. General Information on PTP!13.....................................................................................................
9.1. TIME AND PHASE!13................................................................................................
9.2. WHAT IS PTP?!13.....................................................................................................
9.3. A/V OVER IP APPLICATIONS!13...............................................................................
9.4. PTP DESCRIPTION!13...............................................................................................
9.5. SELECTING A GRANDMASTER!14............................................................................
9.6. SYNCHRONIZATION!14..........................................................................................
9.7. DELAY MEASUREMENT MECHANISM!15..................................................................
9.8. TYPES OF CLOCKS!15..............................................................................................
9.9. PTP DOMAINS!15....................................................................................................
9.10. PTP PROFILES!15....................................................................................................
9.11. EPOCH!15..............................................................................................................
10. PTP Port States!16.......................................................................................................................
Table of Content

DXD8/PTP User Manual (rev 2.15)
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11. Positional change from an External PTP Grandmaster!17...............................................................
11.1 JUMP TO RELOCK!17...............................................................................................
12. Typical PTP use!18......................................................................................................................
12.1 HYBRID SYNC GENERATOR ACCEPTING MULTIPLE REFERENCES!18........................
12.2 DISTRIBUTED PTP VS. INDIVIDUAL GRANDMASTERS WITH GNSS!19.......................
13. PTP v1 (IEEE Std 1588-2002) Implementation - Firmware Option!20..............................................
13.1 SELECTING PTP V1!20.............................................................................................
13.2 DIFFERENCES IN SETTINGS FOR PTP MENU ‘5.2 GRANDMASTER’!20.....................
13.3 DIFFERENCES IN SETTINGS FOR PTP MENUS ‘PORT TIMING’!20.............................
14. AVB - IEEE 802.1as (gPTP) Firmware Option!21............................................................................
15. Guidelines for configuring PTP (Precision Time Protocol)!22...........................................................
15.1 REQUIREMENTS!22.................................................................................................
15.2 RECOMMENDATIONS!22.......................................................................................
15.3 NETWORKING HARDWARE!23...............................................................................
16. Troubleshooting - Error / Warning Messages!23...........................................................................
16.1 PTP ‘NO PORT’ WARNING!23.................................................................................
16.2 PTP PORT IN PASSIVE STATE!23...............................................................................
16.3 TIME JAM TIME OUT!24..........................................................................................
17. Appendix!25..............................................................................................................................
17.1 Appendix A: Factory Presets!25.....................................................................................

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DXD8/PTP User Manual (rev 2.15)
1. Introduction
This manual covers the new functionalities provided by the PTP firmware and is a companion to the main DXD-8 manual. For
general instructions n the DXD-8 operations, please refer to DXD-8 manual.
The DXD-8 Universal Clock is designed to be the central source of time in a modern A/V installation. As a master clock
generator it provides WC, AES and Video Sync. But with the addition of PTP, the DXD-8 truly becomes universal by keeping
traditional audio/video equipment and IP networks in perfect sync.
The DXD-8 has the capability of being a PTP Grandmaster or a PTP slave. As a PTP master, the DXD-8 can lock to external
sync sources such as WC, AES, Video Sync and 10 MHz, or to its internal crystal, while generating PTP sync. As a PTP slave,
it can lock to a Grandmaster while generating traditional sync signals (word clock, AES, video sync or 10MHz).
2. Installation
Before installing the DXD8/PTP, be sure to update your DXD-8 with the latest firmware, available on the Brainstorm website.
When you purchased your DXD/PTP, you received a unique authorization key, a series of 4 numbers, separated by periods.
This key is only valid for the DXD-8 with the serial number used when you placed the order.
Enter this key in Menu 10.5, FEATURE KEYS in the PTP section and press the ENTER key. You will be prompted to confirm your
entry. A message will confirm that the feature key has been set.
This installation procedure only needs to happen once, even with subsequent firmware updates.
IEEE-1588
ETHERNET
PTP
INT
OCXO
ANT
GPS
ETHERNET
UNIVERSAL OUTPUTS
1
2
BNC OUT 1 & 2
BNC OUT 3 & 4
BNC OUT 5 & 6
BNC OUT 7 & 8
5
6
7
8
SYNC
SYNC
SYNC
SYNC
3
4
• WC
• AES
• VID
• 10 MHz
• 1PPS
• WC
• AES
• VID
• 10 MHz
• 1PPS
• WC
• AES
• VID
• 10 MHz
• 1PPS
• WC
• AES
• VID
• 10 MHz
• 1PPS
SYNC
TIME SOURCES
(POSITION)
INT
TCXO
REFERENCE SOURCES
(RATE)
SYNC
TIME
SELECT
REFERENCE
SELECT
ETHERNET
BNC IN B
WC
AES
VID
10MHz
BNC IN A
WC
AES
VID
10MHz
NTP
INTERNAL
TIME OF DAY
CLOCK
&
REFERENCE
FRAME
GENERATOR
DXD-8 DIAGRAM
INT
RTC
ETHERNET
PTP (BMCA)
ANT
GPS
PTP (BMCA)
Rate & Position Rate Only Position Only

DXD8/PTP User Manual (rev 2.15)
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3. Reference & Sync Menus
Installing the PTP option will affect some of the menus and offer new choices. Please refer to the DXD-8 manual for instructions
on how to navigate through the menus and how to change some of the settings..
3.1 REFERENCE MENU (MENU 1.1)
A new choice is available in the reference menu after installing the PTP option: PTP Mode.
•PTP Mode is a little different than other references. Selecting PTP Mode is required for the
DXD-8 to become a PTP slave, i.e. be ‘referenced’ to a PTP Grandmaster. However, selecting
PTP Mode also means that the DXD-8 will participate in the selection process of the PTP
Grandmaster and, depending on the outcome of the BMCA, the DXD-8 will either be a PTP
Slave or the Grandmaster (see 9.5 for more on the BMCA). Explanatory text has been added
to the REFERENCE menu when PTP Mode is activated.
NOTE: When PTP Mode is selected, the PTP port needs to be turned on (menu 5.1). If not, the DXD-8 will lock to its internal
crystal and a ‘PTP"NO"PORT’ warning message will appear in the middle of the display. The LOCK bar at the bottom of the
Main Rotation display will also indicate NO PORT (for more information, see chapter 14.1 Troubleshooting).
•LOCAL REF WHEN GM:
When PTP Mode is selected , if GPS is available, this fields enables GPS to be set as the reference when the DXD-8 is the
Grandmaster. Enabling this field will announce the DXD-8 as GPS referenced, giving it a higher priority at being selected by the
BMCA.
This field only appears if the optional DXD/GPS receiver has been installed.
3.2 SYNC PARAMETERS (MENU 1.2)
New parameters are available in this menu with the PTP options.
•BNC INPUT TIME JAM SOURCE: Selects the source of a Time Jam (see 5.2).
•BNC INPUT TIME JAM RESYNC: Used for a manual Time Jam (see 5.2)
•PTP JUMP THRESHOLD: When the difference between the internal TOD and the PTP reference is above the value entered,
the DXD will not attempt a smooth transition (slew) but will instead jump instantly to the new time.
Value can be adjusted from 5 msec to 15 sec, or set to ‘Never’. Default value is 5"msec.
4. PTP Menus
4.1 PORT MODE (MENU 5.1)
This menu allows you to have PTP enabled or disabled. Choices are ‘on’ and ‘off’.
With the port enabled, the DXD-8 automatically becomes a candidate for PTP Grandmaster. Keep in mind however that it’s
ability to be a PTP slave depends on the reference selection in menu 1.1:
-MASTER/SLAVE: if ‘PTP Mode’ is selected, the DXD-8 can become a PTP slave.
-MASTER-ONLY: if another reference is selected, the DXD-8 can only be a PTP master, not a PTP slave.
NOTE: When the port is enabled and a reference other than ‘PTP Mode’ is selected menu 1.1, if the BMCA selects another
unit as PTP Grandmaster, the port will automatically go in the PASSIVE state.

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DXD8/PTP User Manual (rev 2.15)
4.2 PTP - CLOCK / GRANDMASTER (MENU 5.2)
Menu 5.2 lets you set the following fields for the PTP port.
•Domain: 0 to 127; default = 0
•Priority 1: 0 to 255
•Priority 2: 0 to 255
Priorities are used in the BMCA to select the grandmaster - lower values have a
higher priority (see 9.5 for more information on the Grandmaster selection).
4.3 PORT CONTROLS (MENU 5.3)
•PTP Version: Several versions of PTP are available on the DXD-8:
-PTP 2.0 - Default
-PTP 2.1
-PTP (Layer 2) 2.0
-PTP (Layer 2) 2.1
-AVB 2011 (option)
-AVB 2020 (option)
-PTP v1
•Profile: Different profiles are supported by the DXD-8:
-PTP - Default PTP profile
-AES 67
-ST2059
•Profile Port Timing Action:
Among other things, IEEE1588 profiles define the range and default values of all configurable attributes. This is
very useful as selecting a specific profile on several networks would set all the parameters to the default values
and allow for a quick set up.
Selecting ‘Load profile defaults’ will cause all the timing values to reset to the
profile default values.
Note that, when changing the PTP version or the profile, a message appears,
offering the same option.
•Delay Mechanism: Two different delay mechanism are defined in IEEE 1588:
-E2E: End to End
-P2P: Peer to Peer
Selecting a delay mechanism is done from this menu.
Note that the availability of some of the choices described above for Profile & Delay Mechanism depends on the PTP
version currently selected, as sown in the table below. For example, PTP v1 did not offer profiles and only supported
End-to-End delay mechanism.
VERSION/PROFILE
CHANGE
Do you want to RESET
Timing values to their
Default values?
Press UP to Reset now
Press Any Other Key to Exit
DXD-8 - Menu 5.3 PORT CONTROLS - Choices
PTP Version
PTP Profile
Delay Mechanism
Default
SMPTE ST2059
AES67
E2E
P2P
PTP 2.0
√
√
√
√
PTP 2.1
√
√
√
√
PTP (Layer 2) 2.0
√
√
√
√
√
PTP (Layer 2) 2.1
√
√
√
√
√
AVB 2011
√
√
√
AVB 2020
√
√
√
PTP Version1
√
√
1

DXD8/PTP User Manual (rev 2.15)
Page 7
4.4 PORT TIMING (MENU 5.4)
•Announce Interval: -3 to 4 (1/8sec - 16sec)
Sets the rate at which the master will send Announce messages. These messages
are used to determine which device will be the Grandmaster using the BMCA
(Best Master Clock Algorithm)
Per IEEE 1588 this value should be uniform throughout a domain.
•Announce Receipt Timeout: 2 to 10 announce intervals
Sets the number of Announce messages that can be missed before it is assumed the master is no longer present and the
process of selecting a new one begins.
Per IEEE 1588 this value should be uniform throughout a domain.
•Sync Interval: -7 to 1 (1/128sec - 2sec)
Sets the rate at which the master will send Sync messages.
•Min Delay Req Interval: 1 to 32 the number of Sync Interval
Sets the minimum time interval between 2 adjacent Delay Requests.
This field shows a quantity of sync intervals: “n sync intervals”, where n = 1,2,4,8,16,32 (when n=1 it will say “1
sync interval”).
5. Time of Day
Time of Day is an essential part of the DXD-8 design. In a PTP network, the devices all need to know the Time of Day, i.e. year,
month, day, hour and seconds, even nanoseconds, to achieve frequency and phase synchronization. At the heart of the DXD-8
is the Main Time of Day Clock (TOD) & Reference Frame Generator. This is where System Time is generated and where the
references generated by the DXD-8 are aligned with the PTP epoch.
As shown on the diagram above, some of the reference sources include time and rate information. GPS and PTP for example
carry precise time and date information as well as frequency. However, traditional reference signals, such as video sync or
word clock, only carry the frequency information. When selecting one of those as reference (BNC inputs), the time information
needs to be added from another source. The DXD-8 offers several options.
IEEE-1588
ETHERNET
PTP
INT
OCXO
ANT
GPS
ETHERNET
UNIVERSAL OUTPUTS
1
2
BNC OUT 1 & 2
BNC OUT 3 & 4
BNC OUT 5 & 6
BNC OUT 7 & 8
5
6
7
8
SYNC
SYNC
SYNC
SYNC
3
4
• WC
• AES
• VID
• 10 MHz
• 1PPS
• WC
• AES
• VID
• 10 MHz
• 1PPS
• WC
• AES
• VID
• 10 MHz
• 1PPS
• WC
• AES
• VID
• 10 MHz
• 1PPS
SYNC
TIME SOURCES
(POSITION)
INT
TCXO
REFERENCE SOURCES
(RATE)
SYNC
TIME
SELECT
REFERENCE
SELECT
ETHERNET
BNC IN B
WC
AES
VID
10MHz
BNC IN A
WC
AES
VID
10MHz
NTP
INTERNAL
TIME OF DAY
CLOCK
&
REFERENCE
FRAME
GENERATOR
DXD-8 DIAGRAM
INT
RTC
ETHERNET
PTP (BMCA)
ANT
GPS
PTP (BMCA)
Rate & Position Rate Only Position Only

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DXD8/PTP User Manual (rev 2.15)
5.1 RTC (Real Time Clock)
A backup clock, called the RTC (Real Time Clock) is included in the DXD-8. It is set at the factory (date & time) and runs
continuously, even when the unit is turned off as it is powered by an internal battery.
The DXD uses the date & time information from the RTC just after power up and transfers it to the main TOD (System Time).
When locking to a new reference, if that reference does not have date & time, the TOD simply continues counting along its
current time sequence; if it has date & time, that information is transferred to the TOD.
Although the RTC is set at the factory, it can also be set manually by the operator or be updated automatically (if GPS is
available) via the Real Time Clock menu (menu 7.2).
5.2 Time Jam
Time information can also be received from an external source via the Time Jam mode. This mode is available only when the
reference set in menu 1.1 is one of the BNC inputs as the references available at the BNC inputs do not carry time information,
only rate (Word Clock, AES, Video Sync or 10 MHz). Current choices for Time Jam source are PTP and GPS. The DXD-8’s
System Time will be reset to the time of the Time Jam source before locking to the reference connected to the BNC input selected
in menu 1.1.
5.2.1 TIME JAM TO PTP
When PTP is selected as the source of TIME JAM (menu 1.2), the DXD-8 will first lock its internal
Time of Day clock to PTP. When that is achieved, the DXD-8 will release the PTP Lock and revert
to the BNC source selected in the reference menu.
Reasons to PTP time jam DXD-8’s include:
•Locking to a common video reference (e.g. NTSC) and wanting all of the cross-frame outputs (25 etc.) to be in correct phase
(and epoch), as well as wordclock and AES.
•In a primarily legacy application this is the way to increase the number of legacy outputs and have them all in phase.
•With a timecode license wanting TOD timecode outputs to be in sync, and with correct cross-framing where applicable.
5.2.2 WHAT IS THE SEQUENCE OF A COMPLETE TIME JAM TO PTP?
1. LOCK TO PTP: The DXD-8 Lock status indicates HOLD / PTP SYNC on dark pink background.
2. CONFIRMATION: A message confirms that the date and time information has been transferred to the internal Time of Day
successfully (clearing of this message is required).
3. LOCK TO THE BNC INPUT: The DXD-8 indicates it is locked to the BNC reference, Input a / Video in this example.
4. SYSTEM TIME UPDATED: The System Time now indicates the same time as the PTP source
TIME JAM
A Time Jam to PTP has
completed successfully
Press Any Key to Exit
IMPORTANT NOTE
When using a reference without date & time information such as video sync, there will be a date & time adjustment in
the TOD count so that video frame edges are correctly aligned. The internal TOD is always creating internal
frame references that are aligned as required with Jan 1, 1970 (PTP epoch). To lock to an external
frame edge the DXD has to move the TOD count by up to +/- half a frame to synchronize the internal TOD frame
edge to the incoming edge.

DXD8/PTP User Manual (rev 2.15)
Page 9
5.2.3 WHAT IS REQUIRED FOR A TIME JAM TO PTP?
1. Reference must be BNC A or BNC B (menu 1.1). The BNC input must be set properly in menus 2.1 and/or 3.1.
2. The PTP port must be set as the BNC INPUT TIME JAM SOURCE (menu 1.2). The port will now show as set for Time Jam
[BNC Inputs] in menu 5.1 (blue letters indicate status and cannot be altered)
3. The PTP domain of the Time Jam Port must be set to the same domain as the PTP source in the proper menu (Menu 5.5)
When Time Jam is set as described, the words [Time Jam] will appear at the bottom of the display in the Reference line.
6. Time Menus
6.1 TIME STANDARDS (MENU 7.1)
The following time standards are available on the DXD-8 in addition to the local time:
•TAI: International Atomic Time, (used as a base by other standards such as UTC - no leap seconds).
•UTC: Coordinated Universal Time (time zone ‘0’ - w/ leap seconds).
•GPS: Global Positioning System time (no leap seconds - 19 sec behind TAI and currently 18 sec ahead of UTC).
•Loran: Long Range Navigation time (no leap seconds).
•Local: Local time is based on UTC and can have adjustments for time zone and Daylight Saving (menu 7.1).
With the PTP option, ‘PTP GM’ is added to menu 7.1, for which a time standard can be selected for the display.
•PTP Grandmaster, time received on the Ethernet port from the external PTP Grandmaster.
6.2 TIME & DATE DISPLAY (MENU 7.3)
With the PTP option, ‘Ext PTP Grandmaster’ is added to the list available in menu 7.3, where 2 different DXD times & dates
can be selected for the Time & Date display (see 6.1.2 in the DXD-8 manual).
7. T i m e C o d e M e n u s
Time Code is a separate option available for the DXD-8. It is described in a separate manual (DXD/LTC). However, with the
PTP option, menu 8.1 SMPTE 2059 SET UP becomes available.
7.1 SMPTE 2059 SETUP (MENU 8.1)
The Daily Jam is a process where the time code generator realigns precisely with the epoch
(midnight on Jan 1, 1970 TAI). This process occurs everyday, at the same time, as set in the
DAILY JAM TIME field.
•Daily Jam Time: The value entered in the DAILY JAM TIME field is the amount of time after
midnight, local time, at which the daily jam will occur.
Adjustments can be made in 10 minutes increments. Default value is 01 Hrs 00 Min, i.e. 1:00AM, local time.
•Jam Time Recalculate: Pressing the ENTER key while “Press Enter to Jam” is selected will cause the DXD to recalculate both
Jam Times, the time of the Previous Daily Jam Event and the time of the Next Daily Jam Event.
For time code, the Previous Daily Jam Event is the generator’s anchor point, until the Next Daily Jam Event. When the local
time is too close to the set Daily Jam Time, a manual change will not occur until the next day. By forcing the DXD to recalculate
both jam times manually, the operator has the option to make an immediate change.

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DXD8/PTP User Manual (rev 2.15)
7.2 LTC GENERATOR 1 & 2 (MENUs 8.2 & 8.3)
Menus 8.2 and 8.3 require the DXD/LTC. Otherwise, when trying to access these menus, a message will appear indicating
that the Feature Key has not been found.
Please refer to the DXD/LTC manual for information. To purchase the DXD/LTC, please contact you Brainstorm Electronics dealer.
8. Display
8.1 Main Rotation
8.1.1 MAIN ROTATION FOOTER
•Reference: When PTP Mode is selected in the reference menu, the display in the Main Rotation pages indicates REF: PTP on
the left of the reference line with 4 different options to its right:
-“Master: External”
-“Master: Internal”
-“Master: Internal / OCXO”
-“Master: GPS Receiver”
As explained in 3.1 above, selecting PTP Mode in the reference menu means
that the DXD-8 will participate in the PTP Grandmaster selection (see 9.5,
Selecting a Grandmaster).
If another unit is selected by the BMCA, “Master: External” will be displayed
in the reference line. But, if the DXD-8 is selected, one of the other 3 options
above will be displayed: Internal, Internal /OCXO or GPS Receiver.
•Lock Status: The bottom line of the display has the usual LOCK status, but in the case where the DXD-8 is the grandmaster,
when locked it changes to "LOCKED / GRANDMASTER”.
In case the DXD is or becomes a PTP Salve, when locked it changes to “LOCKED / PTP SLAVE”.
Note that, if another source was selected in the reference menu, such as Video Sync, and the DXD-8 was simultaneously a PTP
Grandmaster, the same LOCK status would appear, but the REF line would indicate “REF: Input A/ Vid” (see example at 12.1).
8.1.2 MAIN ROTATION PAGES
The Main Rotation Pages are the pages appearing on the main display under normal operations, that is when neither the Status
nor the Set Up modes are activated. ‘Rotating’ through those pages is done with the RIGHT and LEFT keys. With the installation
of the PTP option, some pages have been modified, others have been added.
LTC FEATURE KEY NOT FOUND
To purchase please contact your Brainstorm dealer.
Feature Keys are unique for each serial number.

DXD8/PTP User Manual (rev 2.15)
Page 11
•REFERENCE SOURCES - PTP Mode
When PTP Mode is selected in the reference menu, the Reference Sources
page indicates the settings and the state of the PTP port in colors for easy
identification as well as the PTP domain to its right. For details on the PTP
states, see Chapter 10, PTP Ports States.
The small blue box to the right of the PTP state indicates the PTP domain
and the PTP version. For example ‘0:v1’ means Domain 0 and PTP v1.
If GPS is available and has been selected in the reference menu as
‘LOCAL REF WHEN GM’, it will appear on the second section in place of
the ALT REF along with its lock status.
When a source other than ‘PTP Mode’ is selected as the reference, the Reference Sources page will no longer give any
information related to the PTP port. The Lock Line at the bottom of the display will indicate if the port is Grandmaster or
not. To view all the information on the PTP port (PTP domain, PTP version, port state…), press the STATUS button and
look at the PTP PORT STATUS page (see 8.2.3 below).
8.2 Status Pages
Status pages are available on the main display while in the STATUS mode. To activate the STATUS mode, press the [STATUS]
key. The Status LED illuminates to confirm your selection. This firmware update includes the following new Status pages.
8.2.1 TIMES STATUS PAGE
With the PTP option, 4 additional lines have been added to the TIMES status page:
-Grandmaster: time from the external PTP Grandmaster
-TOD-GM Ofst: indicates the offset between the internal Time Of Day clock
and the Grandmaster in µsec.
-Prev Daily: date and time of the previous daily jam
-Next Daily: date and time of the next daily jam
8.2.2 GRANDMASTER ID PAGE
•Primary Clocks:
Three separate Primary Clock ID’s are displayed:
-Distant: When the DXD is locked to a Boundary clock, the distant clock is a
master clock ‘upstream’ from the boundary clock.
-Parent: The clock id of the device the DXD is locked to.
-DXD-8: This clock id of this unit, with [GM] when it is the Grandmaster.
•Grandmaster Credentials:
These are the parameters used by the BMCA to determine the Grandmaster
clock:
-Priority 1,
-Clock Class,
-Clock Accuracy,
-OfstScalLogVar,
-Priority 2
•Path Trace:
When Path Trace is available (AVB & PTP 2.1), all the different boundary clocks that the Announce message traversed are
displayed, up to the grandmaster
Note: Display has been enlarged to show all scrolling options

Page 12
DXD8/PTP User Manual (rev 2.15)
•8.2.3 PTP PORT STATUS PAGE
•The upper section of the PTP Port Status page includes:
-the mode of the port
-the PTP State
-the domain number,
-the delay mechanism,
-the PTP version and
-the PTP profile selected for the port.
•Below that, Message counters display the number of messages received and
transmitted by the port including:
-Announce,
-Sync,
-Delay Request,
-Delay Response,
-Peer Delay Request,
-Peer Delay Response.
Those are running counters and can be cleared by pressing the ENTER key.
Monitoring the messages exchanged is useful when troubleshooting. Announce and Sync messages for example are sent by
Master devices. Delay request & delay response will show PTP activity between Master and slaves and, based on the chosen
Delay Mechanism, the messages will be Delay or Pdelay type.
•Mean Path Delay is the mean travel time of PTP packets between master and slave. The Mean Path Delay is displayed in
µsec.
Note: Display has been enlarged to show all scrolling options

DXD8/PTP User Manual (rev 2.15)
Page 13
9. General Information on PTP
9.1. TIME AND PHASE
Precise time information has always been crucial in traditional production and broadcast environments. To keep the different
video and audio sources synchronized properly, two different references were typically used, one providing time information
(time code), the other phase information (black & burst or tri-level sync for Video, and DARS or Word Clock for Audio). With
IP networks, PTP provides both Time Of Day and phase information, replacing and/or coexisting with the traditional ‘legacy’
references.
9.2. WHAT IS PTP?
PTP (Precision Time Protocol) is a method for precisely synchronizing devices over a computer network. On a LAN, PTP can
achieve clock accuracy to within a microsecond. Originally designed for network measurements, PTP has been broadly
adopted in applications ranging from real-time automations to telecom transmissions and financial transactions.
Published in 2002 by IEEE under the 1588-2002 standard (PTP v1) it was revised in 2008 as 1588-2008 (PTP v2). Version 2
brought several improvements but is not backward compatible with version 1.
9.3. A/V OVER IP APPLICATIONS
PTP has been widely adopted in A/V over IP applications. It is the protocol chosen by AES and SMPTE with PTP profiles
included in both the AES67 and ST-2059 standards. The SMPTE ST-2110 suite of standards (digital video over IP with audio,
video and ancillary data as separate streams) uses PTP for synchronization as it is based on ST-2059.
Major A/V over IP systems such as Dante, Ravenna, Q-LAN, LiveWire and Wheatnet-IP, all use PTP. Although the original
Dante used PTP v1, with the release of the Dante Domain Manager version 1.1, a Dante system has the ability to clock to a
non-Dante PTP v2 clock.
AVB (Audio Video Bridging) is a set of IEEE standards that facilitate the transport of high performance audio and video on a
LAN. One of those standards, IEEE 802.1AS, defines a specific profile of IEEE 1588-2008 with additional timing features
called gPTP (Generalized Precision Time Protocol).
9.4. PTP DESCRIPTION
Per IEEE 1588, PTP uses a hierarchical Master-Slave architecture for clock distribution. The primary timing source is called the
PTP Grandmaster. Precise timestamps are captured at the Master and Slaves and exchanged to determine the offset between
the two and the network latency so that the Slaves can synchronize their internal clocks to the Master’s.
With the PTP protocol, two activities continually occur on the network:
- All grandmaster-capable devices negotiate to select a grandmaster.
- All devices synchronize to the grandmaster.
•BMCA: The Grandmaster is elected autonomously without any user interaction. Grandmaster-capable devices broadcast
their clock “quality” and other parameters with Announce messages. They each compare the received Announce messages
and, independently of the other devices, determine the most suitable grandmaster. This determination is done through the
Best Master Clock Algorithm (BMCA), which by design ensures that all clocks reach the same conclusion. This best master
clock negotiation continues even after a grandmaster has been selected so that in case the current grandmaster fails another
clock can quickly replace it.
•SYNC: Synchronization to the grandmaster is done using a series of messages. Sync messages are broadcasted periodically
by the grandmaster and contain timestamps from its internal clock. Slaves read these messages and adjust their internal
clocks to match exactly the master’s. Every update cycle, the slaves calculate corrections for offset and network latency to
achieve high precision synchronization.

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DXD8/PTP User Manual (rev 2.15)
9.5. SELECTING A GRANDMASTER
An algorithm called the BMCA (Best Master Clock Algorithm) is used to determine which clock will be used as the PTP
Grandmaster. As defined in the IEEE 1588 standard, this selection is done autonomously based on the following criteria and in
the following order:
-Priority 1
-Clock Class
-Clock Accuracy
-Clock Variance
-Priority 2
-Source Port ID (MAC Address)
Of those fields, two are set manually by the users, Priority 1 and 2, so that preferred masters can be prioritized. It is important
to note that, even though through the use of the Priority fields a user can more or less determine which unit will be selected as
Grandmaster, it is still the BMCA that makes that determination.
When a Grandmaster has been selected, all other devices on the domain will sync their internal clocks to that of the
Grandmaster. If the Grandmaster fails or disappears, a new one is selected immediately via the BMCA. If a better suited clock
is found, it will become the Grandmaster.
9.6. SYNCHRONIZATION
There are several different PTP messages used during synchronization, sequenced as follows:
1. The grandmaster sends a Sync message with its transmit timestamp (t1), and an optional Follow Up message, in case of the
two steps operation, which also includes t1.
2. The slave receives the Sync/Follow Up message, keeps its timestamp (t1) and the Sync message arrival time (t2).
3. The slave sends a Delay Request message back to the grandmaster. This message does not include a timestamp, however
the slave keeps the time it sent the Delay Request message (t3).
4. The master receives the Delay Request message and keeps its arrival time (t4). The master then sends back a Delay
Response message including t4.
The slave clock now possesses all four timestamps (t1, t2, t3 and t4) that can be used to compute the offset of the slave clock
relative to the master, and the propagation time between the two clocks. With this, it can now adjust its clock to match the GM
clock.
Master
Clock Time
Slave
Clock Time
t1
t2
t3
t4
Data at
slave clock
t1, t2
t2
t1, t2, t3
t1, t2, t3, t4
Formulaes
Delay = [(t2 - t1) - (t4 - t3)] / 2
Offset = t2 - t1 - Delay

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9.7. DELAY MEASUREMENT MECHANISM
To synchronize clocks, the delay between the clocks must be known. There are two mechanisms to measure the delay called
End to End (E2E) and Peer to Peer (P2P).
•The E2E delay mechanism was the only one included in the original IEEE1588-2002. It measures the delay between
the master and the slave.
E2E uses the following messages, as described in 1.6. above: Sync, Follow-up (optional), Delay_Req, and Delay_Resp.
It can be used with switches or routers that are not 1588 capable.
•The P2P delay mechanism was introduced in IEEE15880-2008. It measures the delay between directly connected
ports. Peer-to-peer delay measurement works “locally”, from every node to each of its neighbors. For each pair of
directly connected ports, each end periodically measures the round-trip network delay by sending a Pdelay_Req
message and receiving in response a Pdelay_Resp message. This way all ports learn the delay on their link.
P2P uses messages Pdelay_Req, Pdelay_Resp, and Pdelay_Resp_Follow_Up (optional).
NOTE: An ordinary clock, which has just one port, can be configured for end-to-end or for peer-to-peer; a boundary clock,
which can have a single slave port and multiple master ports, can be configured for E2E on some ports and P2P on others.
While a single domain can have both end-to-end and peer-to-peer delay mechanisms running simultaneously, all clocks on a
single PTP communication path must use the same method to measure the time delay.
9.8. TYPES OF CLOCKS
IEEE 1588 defines three different types of clocks:
•Ordinary Clock (OC)
•Boundary Clock (BC)
•Transparent Clock (TC)
Ordinary Clocks (OC) are devices with a single port, usually at either end of a network such as A/V equipment, DAW’s or
speakers. They can be master or slave.
Boundary (BC) and Transparent (TC) Clocks are network devices such as switches or routers.
Since the DXD-8 has 1 Ethernet port, it is an ordinary clock (OC).
9.9. PTP DOMAINS
A PTP domain is a network (or a portion of a network) within which all of the clocks are in sync. A single network can have
multiple PTP domains operating separately, e. g., one set of clocks synchronized to one time scale and another set of clocks
synchronized to an other time scale.
9.10. PTP PROFILES
A PTP Profile defines the range and default values of all configurable attributes as well as all required, permitted, or prohibited
clock types and options for a specific application area. Profiles can be created by recognized standards associations such as
AES or SMPTE. The DXD supports the AES67 Media profile and the SMPTE ST-2059-2 profile. The DXD also support the 1588
default profile.
9.11. EPOCH
PTP uses the concept of an Epoch clock. This is an absolute time value when the clock was set to zero, and the number of
1GHz clock pulses that have occurred since provides the current time, converted with software into year, month, day, hours,
minutes and seconds. The Epoch (or zero time) for PTP was set at midnight on the 1st January 1970 (TAI).

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DXD8/PTP User Manual (rev 2.15)
10. PTP Port States
When PTP MODE is selected as the reference, the REFERENCE SOURCES Status Display page indicates the PTP state of the
DXD-8. This is similar to the PTP PORTS page on the DXD-16 where all 4 ports are shown.
The different states are:
•SLAVE: when another unit has been selected as Grandmaster by the BMCA, the DXD-8 acts as a PTP Slave
•GRANDMASTER: when the BMCA chooses the DXD-8 as PTP Grandmaster.
•MASTER: transitional state before the Grandmaster state is confirmed by the BMCA
NOTE: as the DXD-8 has the ability to be a PTP Master or Slave, it means that, per IEEE1588, the state of the port can
change. The BMCA determines what unit becomes the Grandmaster. If the current Grandmaster disappears or looses
GPS, another Grandmaster is selected. For more on the Grandmaster selection, go to 9.5.
The PTP setting is displayed in white letters on a dark grey background. Choices are: Port on / Port off
Then the port’s PTP State is displayed as it changes, in bold letters with the following colors:
The PTP domain number of the DXD-8, as set in menu 5.2, is indicated to the right of the PTP state in a small blue rectangle.
If GPS is available and has been selected in the reference menu as LOCAL REF WHEN GM, it will appear on the second
section in place of the ALT REF with its current lock status right under.
- SLAVE
black letters
yellow background
- GRANDMASTER
black letters
bright green background
- MASTER
white letters
green background

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11. Po s i t i o n a l c h a n g e f r o m a n E x t e r n a l P T P G r a n d m a s t e r
When the DXD is referenced to an external PTP Grandmaster and a disruption or an error causes a positional change in
the PTP Grandmaster, the DXD will respond differently based on how it has been set by the operator.
11.1 JUMP TO RELOCK
One of the parameters in menu 1.2 is the PTP Jump Threshold.
When the time difference detected between the external PTP GM and the DXD System Time is above the PTP Jump
Threshold value, the DXD will jump to the new time and relock through the normal lock procedure. This will cause
disruptions on the output signals but will be the fastest way to be locked with the external PTP GM.
The Jump Threshold can be adjusted in menu 1.2 from 5 msec to 15 sec, or set to ‘Never’ (default value is 5"msec)..
Keep in mind that, with a 15 seconds Jump Threshold, it could take the DXD-8 a long time to slew back in sync. During
that time, the lock status will indicate HOLD / PTP SYNC (see ch. 11 above).

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DXD8/PTP User Manual (rev 2.15)
12. Typical PTP use
The DXD-8 was designed to be a reliable high precision sync generator as well as a very flexible one. Several features were
incorporated in the design with flexibility in mind such as the universal outputs. For PTP, several options are available giving
the user many choices.
12.1 HYBRID SYNC GENERATOR ACCEPTING MULTIPLE REFERENCES
One of the original concept behind the DXD line was to generate ‘legacy’ sync and PTP sync simultaneously so that all
equipment could be kept perfectly synchronized. But, for added flexibility, the DXD-‘s can also be set up to lock to any
‘legacy’ sync or to PTP as illustrated below. These choices are available in the Reference menu.
To reference an IP island to black burst (traditional infrastructure), set the DXD-8 as follows:
-Reference = INPUT A/Vid
-Port Mode = On
-Priority 1 = Low enough to win the BMCA (preferred master)
➡The IP Island locks to the PTP port (Master state)
To reference a legacy island to PTP (IP infrastructure), set the DXD-8 as follows:
-Reference = PTP Mode
-Port Mode = On
➡The Legacy Island locks to BNC outputs (WC, AES, Video Sync, as required)
A/V OVER IP
EQUIPMENT
WORD CLOCK PTP
GRANDMASTER
HOUSE SYNC
BLACK & BURST

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12.2 DISTRIBUTED PTP VS. INDIVIDUAL GRANDMASTERS WITH GNSS
In this example, DXD-8’s are installed in several studios. In order to keep them in sync, 2 different options are available:
-Distributed PTP
-Individual Grandmasters with GNSS reference
The first illustration shows distributed PTP where all the DXD-8’s are PTP slaves to an external Grandmaster; in the second
illustration, the DXD-8’s are all Grandmaster for their networks and each is locked to GNSS. This second solution is
particularly useful when distances between studios are long and certainly for remote trucks.
PTP GRANDMASTER
STUDIO 1 STUDIO 2 STUDIO 3 STUDIO 4 STUDIO 5
PTP GRANDMASTER PTP GRANDMASTER PTP GRANDMASTER PTP GRANDMASTER
Individual Grandmasters with GNSS Reference
PTP SLAVE
STUDIO 1
PTP SLAVE
STUDIO 2
PTP SLAVE
STUDIO 3
PTP SLAVE
STUDIO 4
PTP SLAVE
STUDIO 5
PTP
GRANDMASTER
Distributed PTP

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13. PTP v1 (IEEE Std 1588-2002) Implementation - Firmware Option
The translation between PTPv1 and PTPv2 is implemented as specified in section “18. Compatibility Requirements” of IEEE Std
1588-2008 (PTPv2). It is available on the DXD-8 with the PTP option (DXD8/PTP).
13.1 SELECTING PTP V1
PTPv1 mode is selected in the PTP menu PORT CONTROLS. Select “PTP Version 1” in the line
“PTP VERSION”.
13.2 DIFFERENCES IN SETTINGS FOR PTP MENU ‘5.2 GRANDMASTER’
•Domain:
The range of Domain numbers in PTPv1 is just 0~3, as opposed to 0~127 for PTPv2.
If a Domain number greater than 3 is set for a port running in PTPv1 mode, then:
-The DXD will issue the warning "PTP: Domain Number exceeds PTP-V1 limit"; and
-The actual number used on the bus will be converted to lie in the range 1~3
(4 →1, 5 →2, 6 →3, 7 →1, 8 →2, etc.).
•Priority 1:
PTPv1 does not have PRIORITY settings, but it does have the concept of “Preferred Master Clock”.
Translation between the two is as follows:
PRIORITY 1 = 127 ....... Preferred Master Clock = TRUE
PRIORITY 1 = 128 ....... Preferred Master Clock = FALSE
Other values may be used for PRIORITY 1, with all values less than 127 resulting in Preferred Master Clock being TRUE,
and all values greater than 128 making Preferred Master Clock FALSE.
•Priority 2:
Translation of this value is more obscure. PTPv1 keeps track of whether or not a device is a Boundary Clock, and PTPv2
PRIORITY 2 is mapped to that setting as follows:
PRIORITY 2 = 127 (or less) ....... Boundary Clock = TRUE
PRIORITY 2 = 128 (or more) ....... Boundary Clock = FALSE
Changing PRIORITY 2 will not necessarily result in observable operational differences.
13.3 DIFFERENCES IN SETTINGS FOR PTP MENUS ‘PORT TIMING’
•Announce Interval:
PTPv1 does not use Announce messages, but the DXD-8 continues to use this timing value internally while operating in
PTPv1 mode. The value is not critical, but it is used in the calculation of the SYNC message timeout (see below).
•Announce Receipt Timeout:
Although PTPv1 does not use Announce messages, the DXD-8 port in PTPv1 mode will use this value to determine
whether or not PTPv1 SYNC messages have timed out (i.e. stopped arriving). Note that the timeout is measured in
ANNOUNCE INTERVAL’s (above), whereas PTPv1 measures its SYNC message timeout in SYNC INTERVAL’s. The math
is not difficult, but it may be simpler if the ANNOUNCE INTERVAL is set the same as the SYNC INTERVAL.
The PTPv1 default for this setting is 10 SYNC INTERVAL’s.
ERROR
PTP Domain Number
exceeds PTP-V1 limit
Press Any Key to Clear
CAUTION: Using values _other_ than 127 and 128 in a system where both V2 and V1 devices are present is
_not recommended_ as the V2 devices will recognize the differences between priorities beyond 127 and 128,
and their Best Master Clock algorithms will respond accordingly, whereas the V1 devices will not.