Comtech EF Data CDM-625A - Manual (Page 665)

CDM-625A Advanced Satellite Modem MN-CDM625A
Appendix K Revision 3
K–17
Symbol Designation Function
Master The Master device maintains the clocks.
Slave The Slave device synchronizes its clock to the Master device’s clock.
Figure K-14. PTP Master/Slave Assignment Example
As shown in Figure K-14:
• The first segment is between the RNC/BSC and the CDM-625A ‘A’ (near-end modem) LAN
port. In this segment, the RNC/BSC is the master, and the near-end modem LAN port is the
slave.
Using the CDM-625A ‘A’ front panel or its Web Server Interface, set the PTP Grandmaster
on this near-end modem as LAN.
• The second segment is from the CDM-625A ‘A’ (near-end modem) WAN port to the CDM-
625A ‘B’ (distant-end modem) WAN port, in which the near-end modem WAN port is the
master and the distant-end modem WAN port is the slave.
Using the CDM-625A ‘B’ front panel or its Web Server Interface, set the PTP Grandmaster
on this distant-end modem as WAN.
Accordingly, the third segment between the CDM-625A ‘B’ (distant-end modem) LAN port
and the BTS defines the distant-end modem’s LAN port as the master and the BTS as the
slave.
As configured here, each modem has established independent Wireless Receiver/Transmitter
(WRT) protocol segments – one for LAN and other one for WAN. This defines the boundary clock
time distribution configuration, where the slave to one interface provides a master clock to the
other interfaces.
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