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5.2 PRODUCT SETUP
•
In unusual cases where the length of the link is different in different directions, this setting should be set to the number
of nanoseconds the Ethernet propagation delay to the relay is longer than the mean of path propagation delays to and
from the relay. For instance, if it is known say from the physical length of the fibers and the propagation speed in the
fibers that the delay from the relay to the Ethernet switch it is connected to is 9 000 ns and the that the delay from the
switch to the relay is 11 000 ns, then the mean delay is 10 000 ns, and the path delay asymmetry is 11000 - 10000 =
+1000 ns.
STRICT POWER PROFILE
•
Power profile (IEEE Std C37.238 2011) requires that the relay only select as a grandmaster power profile compliant
clocks, that the delivered time have worst-case error of ±1 µs, and that the peer delay mechanism be implemented.
With the strict power profile setting enabled, the relay will only select as master clocks displaying the IEEE_C37_238
identification codes. It will use a port only when the peer delay mechanism is operational. With the strict power profile
setting disabled, the relay will use clocks without the power profile identification when no power profile clocks are pres-
ent, and will use ports even if the peer delay mechanism is non-operational.
•
This setting applies to all of the relay's PTP capable ports.
PTP DOMAIN NUMBER
•
This setting should be set to the domain number of the grandmaster-capable clock(s) to be synchronized to. A net-
work may support multiple time distribution domains, each distinguished with a unique domain number. More com-
monly, there is a single domain using the default domain number zero.
•
This setting applies to all of the relay's PTP capable ports.
PTP VLAN PRIORITY
•
This setting selects the value of the priority field in the 802.1Q VLAN tag in request messages issued by the relay's
peer delay mechanism. In compliance with PP the default VLAN priority is 4, but it is recommended that in accordance
5
with PTP it be set to 7.
•
Depending on the characteristics of the device to which the relay is directly linked, VLAN Priority may have no effect.
•
This setting applies to all of the relay's PTP capable ports.
PTP VLAN ID
•
This setting selects the value of the ID field in the 802.1Q VLAN tag in request messages issued by the relay's peer
delay mechanism. It is provided in compliance with PP. As these messages have a destination address that indicates
they are not to be bridged, their VLAN ID serves no function, and so may be left at its default value.
•
Depending on the characteristics of the device to which the relay is directly linked, VLAN ID may have no effect.
•
This setting applies to all of the relay's PTP capable ports.
c) SNTP PROTOCOL
PATH: SETTINGS
PRODUCT SETUP
SNTP PROTOCOL
The B90 supports the Simple Network Time Protocol specified in RFC-2030. With SNTP, the B90 can obtain clock time
over an Ethernet network. The B90 acts as an SNTP client to receive time values from an SNTP/NTP server, usually a ded-
icated product using a GPS receiver to provide an accurate time. Both unicast and broadcast SNTP are supported.
If SNTP functionality is enabled at the same time as IRIG-B, the IRIG-B signal provides the time value to the B90 clock for
as long as a valid signal is present. If the IRIG-B signal is removed, the time obtained from the SNTP server is used. If
either SNTP or IRIG-B is enabled, the B90 clock value cannot be changed using the front panel keypad.
5-42
REAL TIME CLOCK
SNTP FUNCTION:
Disabled
SNTP SERVER IP ADDR:
MESSAGE
0.0.0.0
SNTP UDP PORT
MESSAGE
NUMBER: 123
B90 Low Impedance Bus Differential System
SNTP PROTOCOL
Range: Enabled, Disabled
Range: Standard IP address format
Range: 0 to 65535 in steps of 1
5 SETTINGS
GE Multilin
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