Spectracom VelaSync 1225, User Manual, Page: 100 / 272

Settings changed by the user will be maintained when the PTP daemon is stopped and
started, and between reboots and powercycles.
Figure 2-11:
Edit PTP Settings panel
Protocol tab
PTP version : [1, 2] Select Version 1 or Version 2.
Domain : [1 through 127] Sets the current PTP Domain Number, as defined in
IEEE Std 1588-2008 Section 7.1
Communication Mode : Select multicast, hybrid, or unicast mode.
A b o u t … P T P T r a n s m i s s i o n M o d e s
The PTP Card is able to transmit the PTP packets in three transmission modes:
• Multicast Mode
: PTP packets are transmitted to all PTP Clocks by means of
Multicast IP addresses dedicated to the PTP protocol (224.0.1.129, 224.0.0.107). PTP
packets received by the PTP Clocks are then filtered from the Domain Number, the
Port Identity (Clock Id Port Number) of the transmitter. When the Master
Clock is set in Multicast mode, this module will deny the requests from the Slaves
Clocks to run in Unicast mode. When the Master Clock is set in Unicast mode, it
doesn’t transmit any PTP messages until a Slave has been granted to run in Unicast
mode.
• Unicast Mode
: This is a Point- to- Point transmission mode between two PTP
Clocks by means of the unique IP address assigned to each PTP Clock.
• Hybrid Mode
: [default] This mode uses Multicast messages for Sync, Follow-Up,
and Announce packets from the Master. Slaves are expected to send Delay Request
messages to the Master in Unicast, and the Master responds in Unicast. No Unicast
Negotiation grants are necessary.
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VelaSync User's Manual Rev. 3
2.11 Configuring PTP