Time synchronization ensures that every Media Server in a Site uses the exact same time as a reference. Recording timestamps, event logs, timelines, bookmarks, and audit trails rely on a single Site-wide clock. If server clocks differ, you cannot align or review footage from multiple cameras on a single timeline.

How time synchronization works

The VMS distinguishes between two time values:

• Current Site time: The synchronized time shared by every Media Server in the Site. The VMS uses this value for recording, event triggers, and timeline playback.

• Local server time: The operating system (OS) clock and local time zone of an individual server.

The VMS calculates an internal offset to maintain the Site time and never alters the server's underlying OS clock.

Synchronization schedule

The VMS updates and checks time based on the following rules:

• Every 10 minutes: Media Servers refresh the site time over the network.

• On settings change: Updating any time synchronization setting triggers an immediate resynchronization.

Synchronization modes

You can configure time synchronization in one of three modes:

• Synchronize with the internet (default): The Site automatically selects the server with the fastest internet connection. That server fetches external time over TCP port 37 using the TIME protocol. All other servers sync their time from this primary server using the internal API.

• Synchronize with a selected Media Server: You choose one Media Server to serve as the time source for the site. The Site makes no external network requests. Use this mode for isolated or air-gapped networks.

• Do not synchronize: Each Media Server relies independently on its own local OS clock.

Check Media Server time using the REST API

To verify the current Site time, OS time, and time zone settings for a specific Media Server, send an HTTP GET request using a browser or API tool.

1. Open your browser or HTTP client.

2. Enter the following URL, replacing <serverAddress> with your server's IP address or hostname:

   https://<serverAddress>:7001/rest/v4/servers/this/runtimeInfo?_with=synchronizedTimeMs,osTimeMs,timeZoneId,timeZoneOffsetMs

3. Review the JSON response:

   • synchronizedTimeMs: The current VMS  Site time in milliseconds.

   • osTimeMs: The local server OS clock time in milliseconds.

   • timeZoneId: The local server time zone identifier.

   • timeZoneOffsetMs: The local server time zone offset in milliseconds.