Transition Networks SISGM-CHAS L2, Руководство пользователя

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Transition Networks SISGM
–CHAS L2/L3 Switch User Guide
33625 Rev. B https://www.transition.com/ Page 194 of 234
master clock, the slave then request Sync messages from the selected
master.
Duration
The number of seconds a master is requested to send Announce/Sync
messages. The request is repeated from the slave each Duration/4 seconds.
ip_address The IPv4 Address of the Master clock.
Grant The granted repetition period for the sync message.
CommState
The state of the communication with the master, possible values are:
IDLE : The entry is not in use.
INIT : Announce is sent to the master (Waiting for a response).
CONN : The master has responded.
SELL : The assigned master is selected as current master.
SYNC : The master is sending Sync messages.
PTP Configuration Example
This example describes how to configure the
switch as an Ordinary “master” clock and ordinary
“slave” clock.
IEEE 1588v2 is a packet based timing protocol. Ethernet packets are sent with timestamps, and
the received packets have the timestamps read so the timing (and thus frequency) can be derived.
Network timing is hierarchical in nature, such that there is one master that transmits to a large (or
infinite) number of slaves. The master source clock can be an SISGM switch, or it can be another
device. If it is another device the SISGM switch has two methods to get the master clock timing.
If it is another device, it can get the master timing input from either a packet or a 1 pulse per
second hardware input pin (1PPS).
If the switch is to give timing information to other devices, the switch can provide it as a packet, or
as an output hardware pin as a 1PPS.
The initial release of the SISGM switch does not have the input/output pins available for the 1PPS
use for external devices, either master clocks or handoff to slave’s device. However, the 1588v2
for packet is still available to be used, and is fully functional.
Typically, the SISGM switch is a used as a device that passes through the packets and adjusts the
timestamps per the protocol. As such the I/O 1PPS pins would not be used for these
environments.