SPG8000A Option PTP operation instructions
Domain. Defaults to a reasonable setting for each profile. Users are not
allowed to set both PTP engines to the same domain.
Communication mode. All of the master and slave devices on a given domain
must use compatible communication modes. For most profiles, this means
the master and slave communication modes need to match exactly. On the
SMPTE profile, the Multicast and Mixed modes are compatible, so a master
in any of these modes will work with a slave in any of those modes.
Unicast is separate and the master and slave must match. Note that the
Unicast, and Mixed without negotiation modes require that the IP address
of all the masters be entered into the Acceptable Master Table (AMT) of
the slave.
Announce interval allows setting the rate at which the master will send
announce messages. For Unicast mode there are two settings: Desired and
Required. The slave will start by requesting the Desired rate. If the master
refuses that rate, the slave will request a slower rate. This continues down
to the Required setting. If the master cannot support the Required setting,
the communication will not start. The default for the Required setting is the
minimum rate / maximum interval allowed in the profile.
Sync interval allows setting the rate at which the master will send sync
messages. For Unicast mode there are two settings: Desired and Required.
The slave will start by requesting the Desired rate. If the master refuses that
rate, the slave will request a slower rate. This continues down to the Required
setting. If the master cannot support the Required setting, the communication
will not start. The default for the Required setting is the minimum rate /
maximum interval allowed in the profile.
Delay Message allows setting the rate at which the master will send delay
request messages. For Unicast mode there are two settings: Desired and
Required. The slave will start by requesting the Desired rate. If the master
refuses that rate, the slave will request a slower rate. This continues down
to the Required setting. If the master cannot support the Required setting,
the communication will not start. The default for the Required setting is the
minimum rate / maximum interval allowed in the profile.
Announce timeout count sets the number of announce messages which can be
missed before the device will assume the master is no longer present. After
that time, all the devices on the domain will start the process of selecting a
new master.
Priority 1 and 2 are used in the BMCA to select the active master. Typically,
all the masters should have the Priority 1 parameter set to the same value,
and then use the Priority 2 parameter to select the primary master if all have
the same clock quality. A lower value is preferred. For example, if you set
the Priority 2 parameter of the primary master to 127, then set the Priority 2
parameter of all other masters to 128.
4
