Cisco Nexus 5600 Series - NTP as Time Server; Distributing NTP Using CFS; Clock Manager; High Availability

Before synchronizing, NTP compares the time reported by several network devices and does not synchronize
with one that is significantly different, even if it is a stratum 1. Because Cisco NX-OS cannot connect to a
radio or atomic clock and act as a stratum 1 server, we recommend that you use the public NTP servers
available on the Internet. If the network is isolated from the Internet, Cisco NX-OS allows you to configure
the time as though it were synchronized through NTP, even though it was not.
You can create NTP peer relationships to designate the time-serving hosts that you want your network
device to consider synchronizing with and to keep accurate time if a server failure occurs.
Note
The time kept on a device is a critical resource, so we strongly recommend that you use the security features
of NTP to avoid the accidental or malicious setting of incorrect time. Two mechanisms are available: an access
list-based restriction scheme and an encrypted authentication mechanism.
NTP as Time Server
Other devices can configure it as a time server. You can also configure the device to act as an authoritative
NTP server, enabling it to distribute time even when it is not synchronized to an outside time source.
Distributing NTP Using CFS
Cisco Fabric Services (CFS) distributes the local NTP configuration to all Cisco devices in the network.
After enabling CFS on your device, a network-wide lock is applied to NTP whenever an NTP configuration
is started. After making the NTP configuration changes, you can discard or commit them.
In either case, the CFS lock is then released from the NTP application.
Clock Manager
Clocks are resources that need to be shared across different processes.
Multiple time synchronization protocols, such as NTP and Precision Time Protocol (PTP), might be running
in the system.
High Availability
Stateless restarts are supported for NTP. After a reboot or a supervisor switchover, the running configuration
is applied.
You can configure NTP peers to provide redundancy in case an NTP server fails.
Cisco Nexus 5600 Series NX-OS System Management Configuration Guide, Release 7.x
220 OL-31641-01
Configuring NTP
NTP as Time Server