Network Time Protocol Client

Introduction

Sierra Chart has an advanced Network Time Protocol implementation to synchronize your local computer clock to a highly accurate network time protocol server which references an atomic clock.

This feature is used to ensure your clock is within milliseconds, of the actual time. The Network Time Protocol client is implemented in a way to ensure continuous high accuracy of your local computer clock.

Usage

The NTP client can be enabled in Sierra Chart with the default settings through Global Settings >> NTP Settings. In that window, set Enable NTP Client to Yes. Press OK.

The system will initially try to adjust the clock in a gradual manner, updating the clock to slowly move to the time defined by the servers. If a gradual adjustment is not allowed due to operating system settings, then a single time adjustment will take place.

Settings

The following settings are available:

• NTP Client Enabled: When this is set to Yes then the NTP Client is set to modify the computer clock based on the settings on this window
• NTP Servers: This is a list of NTP servers that will be used to establish the time for the computer. NTP servers can be added, removed, or the list reset, using the buttons below this entry.
• [Add] button: Enter a new NTP server in the NTP Servers list and then select this [Add] button to add that NTP server to the list.
• [Remove] button: Select an NTP server in the NTP Servers list and then select this [Remove] button to remove that NTP server from the list.
• [Reset] button: Select this button to reset the list of NTP Servers to the default.
• Last Offset Value: This is a read-only field that displays the last offset value that was used to adjust the time.
• System Clock rate adjust: This is a read-only field that displays the rate at which the clock will be adjusted. This is only valid if the computer clock can be adjusted gradually.
• System Poll Period: This is a read-only field that displays how often the NTP client will poll the NTP servers for the correct time. This value can be adjusted using the [Reduce System poll period] and [Increase System poll period] buttons. The lowest Poll Period that can be set is 16 seconds. The highest Poll Period that can be set is 256 seconds.
• [Reduce System poll period]: Selecting this button will reduce the System Poll Period. The reduction is done by dividing the current value in half. The lowest value for the Poll Period is 16 seconds.
• [Increase System poll period]: Selecting this button will increase the System Poll Period. The increase is done by multiplying the current value by 2. The highest value for Poll Period is 256 seconds.

Additional Implementation Notes

The Network Time Protocol client in Sierra Chart is based upon RFC 5905.

Sierra Chart uses multiple NTP peers at the same time using the UDP protocol. The reason for this is that the connection to a single peer may not be fast or stable or there may not be a symmetric time between sending and receiving.

By using multiple peers, we are able to determine the correct offset value to correct the system clock. The more NTP peers that Sierra Chart connects to, means a more accurate offset value for correcting the system clock.

When the NTP Client when it is destroyed/deleted within Sierra Chart, it releases all resources and returns back to the Operating System the time adjustment control.

Multiple threads are used in the NTP client in Sierra Chart for receiving NTP packets, processing these packets and adjusting the system time.