Comtech EF Data CDM-625 - Manual (Page 395)

CDM-625 Advanced Satellite Modem Revision 15
Ethernet Network Configuration MN-CDM625
16–17
• When the modem must synchronize with the Grandmaster over the WAN interface, set
Grandmaster to WAN.
When Grandmaster is WAN, the modem will set its PTP Clock Priority1 value to 1 (the highest)
to force slave devices that use the BMC algorithm to accept the modem as the PTP master.
Symbol Designation Function
Master The Master device maintains the clocks.
Slave The Slave device synchronizes its clock to the Master device’s clock.
Grandmaster The root timing reference that transmits synchronization information to the clocks
residing on its network segment.
Figure 16-14. PTP Master/Slave Assignment Example
As shown in Figure 16-14:
• The first segment is between the RNC/BSC and the CDM-625 ‘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-625 ‘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-625 ‘A’ (near-end modem) WAN port to the
CDM-625 ‘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-625 ‘B’ front panel or its Web Server Interface, set the PTP Grandmaster
on this distant-end modem as WAN.
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