Explains how Network Time Protocol (NTP) servers synchronize device clocks across a network to ensure accurate and consistent timekeeping.
A Network Time Protocol (NTP) server is a network device that
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provides a common, authoritative time source for other devices,
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synchronizes network clocks using the User Datagram Protocol (UDP) and Coordinated Universal Time (UTC), and
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distributes accurate time across the network to maintain consistency and support management, security, and troubleshooting operations.
| Feature Name |
Release Information |
Feature Description |
|---|---|---|
| NTP Support |
Cisco IOS XR Release 7.11.1 |
Network Time Protocol (NTP) allows devices to synchronize clocks with the NTP servers, maintaining the most accurate time. NCS 1010 now supports time synchronization. In modern and large networks, time synchronization is critical because every aspect of managing, securing, planning, and debugging a network depends on the time of occurrence of events. Commands added:
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NTP key features and operation
NTP uses the User Datagram Protocol (UDP) as its transport protocol.
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NTP communication is always based on Coordinated Universal Time (UTC).
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NTP networks usually receive their time from an authoritative source, such as a radio clock or atomic clock attached directly to a time server. NTP distributes this time across the network.
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The "stratum" concept describes the number of NTP hops a machine is from an authoritative time source:
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A stratum 1 server is directly connected to an authoritative source (for example, a radio or atomic clock, or a GPS time source).
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A stratum 2 server receives its time from a stratum 1 server via NTP, and so forth.
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Machines running NTP, called "associations," are usually statically configured with the IP addresses of machines with which they should form associations. Accurate timekeeping is achieved by exchanging NTP messages between each pair of associated machines.
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An NTP broadcast client listens for broadcast messages sent by an NTP broadcast server at a designated IPv4 address. The client synchronizes the local clock using the first received broadcast message.