Beginning with switch software release 16.01, the NTP Client feature is supported on the following switch models covered in this guide:
The Network Time Protocol (NTP) synchronizes the time of day among a set of distributed time servers and clients in order to correlate events when receiving system logs and other time-specific events from multiple network devices. NTP uses the User Datagram Protocol (UDP) as its transport protocol.
All NTP communications use Coordinated Universal Time (UTC). An NTP server usually receives its time from an authoritative time source, such as a radio clock or an atomic clock attached to a time server, and then distributes this time across the network. NTP is extremely efficient; no more than one packet per minute is necessary to synchronize two machines to within a millisecond of each other.
NTP uses a stratum to describe the distance between a network device and an authoritative time source:
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.
The security features of NTP can be used to avoid the accidental or malicious setting of incorrect time. One such mechanism is available: an encrypted authentication mechanism.
Though similar, the NTP algorithm is more complex and accurate than the Simple Network Time Protocol (SNTP).
IMPORTANT: Enabling this feature results in synchronizing the system clock; therefore, it may affect all sub-systems that rely on system time.
The following commands allow the user to configure NTP or show NTP configurations.
This command is used to configure the protocol used for network time synchronization.
Deletes all timesync configurations on the device.
Updates the system clock using TIMEP.
Updates the system clock using SNTP.
Updates the system clock using TIMEP or SNTP (default).
Updates the system clock using NTP
Switch(config)# timesync sntp Update the system clock using SNTP. timep Update the system clock using TIMEP. timep-or-sntp Update the system clock using TIMEP or SNTP. ntp Update the system clock using NTP.
This command is used to update the system clock using NTP.