When Simple Network Time Protocol (SNTP) is configured as a client, the i5/OS® operating system retrieves a time value from an external time source.
You can specify from which sources (up to three) to retrieve the time value. This external time value is compared to the system time. If the system time value does not match the external time source, a time adjustment begins. The system time is adjusted until the required time value is reached.
You can configure the i5/OS operating system as the SNTP client to poll a Network Time Protocol (NTP) or an SNTP server to find the time. The SNTP client updates the system clock. Most applications use the system clock as their time source. By updating the system clock, applications reflect the synchronized time obtained from the time server.
From the time server list, the first server that can provide valid time service is selected. When the selected time server fails, a new time server is selected. The time server should be selected based on the minimum network response time delay at the location where the system is installed.
A list of public time servers is maintained on the Internet. To locate a time server, you can use a search engine with a query of NTP servers.
You can run the SNTP client and the SNTP server concurrently on your system. Then, you can obtain time from an outside source and serve that time to the clients in your network.
Related concepts
Scenario: Synchronizing clocks with i5/OS