SNTP configuration

The Simple Network Time Protocol (SNTP) enables you to synchronize the system time in your network.
The device supports the SNTP client and the SNTP server function.

The SNTP server makes the UTC (Universal Time Coordinated) available. UTC is the time relating to the coordinated world time measurement. The time displayed is the same worldwide. Local time differences are not taken into account.

SNTP uses the same packet format as NTP. In this way, an SNTP client can receive the time from an SNTP server as well as from an NTP server.

Note: For accurate system time distribution with cascaded SNTP servers and clients, use only network components (routers, switches, hubs) in the signal path between the SNTP server and the SNTP client which forward SNTP packets with a minimized delay.

Tab. Switches SNTP on and off globally

Parameters

Meaning

Possible values

Default setting

Operation

Switches the SNTP function on and off globally.

On, Off

Off


Tab. SNTP Status

Parameters

Meaning

Possible values

Default setting

SNTP Status

Displays conditions such as “Server cannot be reached”.

-

-


Tab. Configuration SNTP Client

Parameters

Meaning

Possible values

Default setting

Client Status

Switches the SNTP client on and off.

On, Off

On

External Server Address

IP address of the SNTP server from which the device periodically requests the system time.

Valid IPv4 address

0.0.0.0

Redundant Server Address

IP address of the SNTP server from which the device periodically requests the system time if it does not receive a response to a request from the “External server address” within 0.5 seconds.

Valid IPv4 address

0.0.0.0

Server Request Interval

Time interval at which the device requests SNTP packets.

1 s - 3600 s

30 s

Accept SNTP Broadcasts

Specifies whether the device accepts the system time from SNTP Broadcast/Multicast packets that it receives.

On, Off

On

Threshold for obtaining the UTC [ms]

The device changes the time as soon as the deviation from the server time is above this threshold in milliseconds. This reduces the frequency of time changes.

0 - 2147483647 (231-1)

0

Disable Client after successful Synchronization

Enable/disable further time synchronizations once the client, after its activation, has synchronized its time with the server.

On, Off

Off


Note: If you have enabled PTP at the same time, the SNTP client first collects 60 time stamps before it deactivates itself. The device thus determines the drift compensation for its PTP clock. With the preset server request interval, this takes about half an hour.
Note: If you are receiving the system time from an external/redundant server address, switch off the reception of SNTP Broadcasts (see “Accept SNTP Broadcasts”). You thus ensure that the device only takes the time from a defined SNTP server.

Tab. Configuration SNTP-Server

Parameters

Meaning

Possible values

Default setting

Server Status

Switches the SNTP server on and off.

On, Off

On

Anycast Destination Address

IP address, to which the SNTP server of the device sends the SNTP packets 'Destination address classes for SNTP and NTP packets'.

Valid IPv4 address

0.0.0.0

VLAN ID

VLANs to which the device periodically sends SNTP packets.

1-4042

1

Anycast Send Interval

Time interval at which the device sends SNTP packets.

1 - 3600

120

Disable Server at local Time Source

Enables/disables the SNTP server function if the status of the time source is local (see Time dialog).

On, Off

Off


Tab. Destination address classes for SNTP and NTP packets

IP destination address

Send SNTP packet to

0.0.0.0

Nobody

Unicast address (0.0.0.1 - 223.255.255.254)

Unicast address

Multicast address (224.0.0.0 - 239.255.255.254), especially 224.0.1.1 (NTP address)

Multicast address

255.255.255.255

Broadcast address


Buttons

Tab. Buttons (Forts.)

Button

Meaning

“Set”

Transfers the changes to the volatile memory (RAM) of the device. To permanently save the changes, open the Basic Settings:Load/Save dialog, select the location to save the configuration, and click “Save”.

“Reload”

Updates the fields with the values that are saved in the volatile memory (RAM) of the device.

“Help”

Opens the online help.