Clock Management - Cisco Nexus 5000 Series Configuration Manual
System management configuration guide
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Also See for Nexus 5000 Series:
- Cli configuration manual (660 pages) ,
- Configuration manual (334 pages) ,
- Command reference manual (196 pages)
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Configuring PTP
• Examines the contents of all received announce messages (issued by ports in the master state)
• Compares the data sets of the foreign master (in the announce message) and the local clock for priority,
• Determines its own state as either master or slave
After the master-slave hierarchy has been established, the clocks are synchronized as follows:
• The master sends a synchronization message to the slave and notes the time it was sent.
• The slave receives the synchronization message and notes the time it was received.
• The slave sends a delay-request message to the master and notes the time it was sent.
• The master receives the delay-request message and notes the time it was received.
• The master sends a delay-response message to the slave.
• The slave uses these timestamps to adjust its clock to the time of its master.
Clock Management
By default, Cisco NX-OS uses NTP to update the system clock. However, if the clock protocol property is
configured to PTP, PTP is allowed to update the system clock.
If PTP is enabled, NTP does not update the system time.
High Availability for PTP
Stateful restarts are supported for PTP. After a reboot or a supervisor switchover, the running configuration
is applied.
Licensing Requirements for PTP
PTP requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS
system images and is provided at no extra charge to you. For a complete explanation of the Cisco NX-OS
licensing scheme, see the Cisco NX-OS Licensing Guide.
Guidelines and Limitations for PTP
• PTP operates only in boundary clock mode. End-to-end transparent clock and peer-to-peer transparent
• PTP supports transport over User Datagram Protocol (UDP). Transport over Ethernet is not supported.
• PTP supports only multicast communication. Negotiated unicast communication is not supported.
• PTP is limited to a single domain per network.
clock class, accuracy, and so on
clock modes are not supported.
Cisco Nexus 5000 Series NX-OS System Management Configuration Guide, Release 5.2(1)N1(1)
Clock Management
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