GE C60 Instruction Manual page 320

PRODUCT SETUP
In networks containing one or more switches and/or clocks that do not implement both of these mechanisms, not all
delays are compensated, so the time of message arrival at the relay is later than the time indicated in the message. This
setting can be used to approximately compensate for this delay. However, as the relay is not aware of network switching
that dynamically changes the amount of uncompensated delay, there is no setting that always and completely corrects
for uncompensated delay. A setting can be chosen that reduces the worst-case error to half of the range between
minimum and maximum uncompensated delay, if these values are known.
PORT 1 ... 3 PATH DELAY ASSYMMETRY
mechanism to compensate for any difference in the propagation delay between the two directions of a link. Except in
unusual cases, the two fibers are of essentially identical length and composition, so make this setting zero.
In unusual cases where the length of the link is different in different directions, set this setting 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 9000 ns and that the delay from the switch to the relay
is 11000 ns, then the mean delay is 10000 ns, and the path delay asymmetry is 11000 - 10000 = +1000 ns.
5.3.7.3 SNTP protocol
SETTINGS  PRODUCT SETUP  REAL TIME CLOCK  SNTP PROTOCOL
 SNTP PROTOCOL

5
The C60 supports the Simple Network Time Protocol specified in RFC-2030. With SNTP, the C60 can obtain clock time over
an Ethernet network. The C60 acts as an SNTP client to receive time values from an SNTP/NTP server, usually a dedicated
product using a GPS receiver. UR family relays support unicast, broadcast, multicast, and anycast SNTP functionality.
The
SNTP FUNCTION
To use SNTP in unicast mode, set
is "Enabled," the C60 attempts to obtain time values from the SNTP/NTP server. Since many time values are
FUNCTION
obtained and averaged, it generally takes three to four minutes until the C60 clock is closely synchronized with the SNTP/
NTP server. It takes up to two minutes for the C60 to signal an SNTP self-test error if the server is offline.
To use SNTP in broadcast mode, set the
then listens to SNTP messages sent to the "all ones" broadcast address for the subnet. The C60 waits up to 18 minutes
(>1024 seconds) without receiving an SNTP broadcast message before signaling an SNTP self-test error.
The
SNTP UDP PORT NUMBER
After enabling and waiting for the synchronization, verify that there is no SNTP Failure message in the Event Records.
Do not set more than one protocol to the same TCP/UDP port number, as this results in unreliable operation of
those protocols.
5.3.7.4 Local time
SETTINGS  PRODUCT SETUP  REAL TIME CLOCK  LOCAL TIME
 LOCAL TIME

5-112
— This setting corresponds to "delayAsymmetry" in PTP, which is used by the peer delay
SNTP FUNCTION:

Disabled
SNTP SERVER IP ADDR:

0.0.0.0
SNTP UDP PORT

NUMBER: 123
setting enables or disables the SNTP feature on the C60.
SNTP SERVER IP ADDR
SNTP SERVER IP ADDR
is 123 for normal SNTP operation. The change takes effect when the C60 is restarted.
LOCAL TIME OFFSET

FROM UTC: 0.0 hr
DAYLIGHT SAVINGS

TIME: Disabled
DST START MONTH:

January
Range: Enabled, Disabled
Range: standard IP address format
Range: 1 to 65535 in steps of 1
to the SNTP/NTP server IP address. Once this address is set and
setting to "0.0.0.0" and
Range: –24.0 to 24.0 hr in steps of 0.5
Range: Disabled, Enabled
Range: January to December (all months)
C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS
to "Enabled." The C60
SNTP FUNCTION
SNTP