Alcatel-Lucent 7450 ESS-12 - PTP Clock Redundancy

System Management
7450 ESS OS Basic System Configuration Guide Page 251
Figure 18: Boundary Clock
In addition, the use of port based timestamping in every network element between the grandmaster
and the end slave application is highly recommended for delivering time to meet one microsecond
accuracies required of mobile applications.
The 7750 SR always uses the frequency output of the central clock to maintain the timebase within
the node. The PTP reference into the central clock should always be enabled as an option if the
7750 is operating in 1588 Boundary Clock mode. This avoids the situation of the node entering
holdover while propagating time with 1588.
PTP Clock Redundancy
The PTP module in the 7450 ESS exists on the CPM. The PTP module on the standby CPM is
kept synchronized to the PTP module on the active CPM. All sessions with external ptp peers are
maintained over a CPM switchover.
Packet
Network
1588v2
Grand
Master
PTP Slave
PTP Slave
PTP Slave
PTP
Boundary
Clock
PTP
Boundary
Clock
PTP
Boundary
Clock
OSSG741
1588v2
Grand
Master