Ntp best practices cisco

1. What is the best practice polling interval for NTP?
2. What is the most accurate NTP server?
3. How many NTP servers should I use?
4. How often should NTP sync?
5. How accurate is NTP time sync?
6. Is NTP traffic UDP or TCP?
7. Should NTP load balance?
8. Is NTP push or pull?
9. What is default polling interval?
10. What is poll interval?
11. What is the default polling interval for Chrony?
12. Is polling better than interrupt?
13. Is polling interrupt more efficient?

What is the best practice polling interval for NTP?

Resolution. NTP dynamically selects the optimal poll interval between the values of minpoll and maxpoll , which default to 64 and 1024 seconds respectively and are correct for most environments.

What is the most accurate NTP server?

As detailed at NTP.org, NTP works in a hierarchical fashion by passing time from one stratum to another. For example, Stratum 0 serves as a reference clock and is the most accurate and highest precision time server (e.g., atomic clocks, GPS clocks, and radio clocks.)

How many NTP servers should I use?

Have at least four NTP servers. Each network system should have at least four NTP servers, and preferably more.

How often should NTP sync?

A properly running (full) NTP client will decide on its own how often to poll the servers you've configured. Initially it will probably check every 64 seconds, but once the clock has been stabilized, the polling may be every 1024s (there's a doubling in the algorithm at every step).

How accurate is NTP time sync?

NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions. Asymmetric routes and network congestion can cause errors of 100 ms or more.

Is NTP traffic UDP or TCP?

NTP is a built-on UDP, where port 123 is used for NTP server communication and NTP clients use port 1023 (for example, a desktop).

Should NTP load balance?

Load balancing NTP doesn't make sense, and can do more harm than good. RFC8633 (NTP Best Current Practice) has a section on anycast, and the same considerations apply to load balancers. If you have only one public IP address, expose just one stratum 2 server to the pool.

Is NTP push or pull?

NTP peer mode

In some instances this is often referred to as the 'push-pull' process, meaning that a peer either pulls or pushes the time value according to the configuration setup.

What is default polling interval?

Last Updated December 23, 2021. The default value of the polling Interval is 5 minutes with a minimum acceptable value of 30 seconds. The polling interval is the frequency at which an agent polls the management server for configuration changes.

What is poll interval?

Determines the frequency at which the service scans the requests queue. The user experiences this interval as the greatest possible delay between initiating an action and the service starting the action.

What is the default polling interval for Chrony?

Client using public servers

The polling interval is automatically adjusted between the default minimum of 64 and maximum of 1024 seconds. As the client is running, it should slowly increase its polling interval to the maximum and reduce the load on the servers.

Is polling better than interrupt?

The main difference between interrupt and polling is that, in the case of an interrupt, the system informs the CPU that it needs attention, while talking about polling, the CPU constantly inspects the status of the system to find whether it needs attention.

Is polling interrupt more efficient?

Based on our experiments, classic polling is the most energy efficient for low-latency requests, and interrupt for high-latency requests.