Configuring Time Synchronization on AOS-Switches

Time synchronization in a switch ensures maintaining a uniform time among all interoperating devices. Aruba Central (on-premises) offers the Simple Network Time Protocol (SNTPSimple Network Time Protocol. SNTP is a less complex implementation of NTP. It uses the same , but does not require the storage of state over extended periods of time.) time synchronization protocol for switches. In SNTP, Aruba Central (on-premises) supports broadcast, unicast, and DHCPDynamic Host Configuration Protocol. A network protocol that enables a server to automatically assign an IP address to an IP-enabled device from a defined range of numbers configured for a given network. modes.

Time synchronization in a switch ensures maintaining a uniform time among all interoperating devices. Aruba Central (on-premises) offers the following time synchronization protocols for switches:

Network Time Protocol (NTPNetwork Time Protocol. NTP is a protocol for synchronizing the clocks of computers over a network.)
Simple Network Time Protocol (SNTP)

To configure time synchronization in a switch, complete the following steps:

In the Network Operations app, select one of the following options:
- To select a switch group in the filter:
  1. Set the filter to a group containing at least one switch.
    The dashboard context for the group is displayed.
  2. Under Manage, click Devices > Switches.
  3. Click the AOS-S or Config icon to view the switch configuration dashboard.
- To select a switch in the filter:
  1. Set the filter to Global or a group containing at least one switch.
  2. Under Manage, click Devices > Switches.
    A list of switches is displayed in the List view.
  3. Click a switch under Device Name.
    The dashboard context for the switch is displayed.
  4. Under Manage, click Device.
    The tabs to configure the switch is displayed.
Click System > Time. The Time page is displayed.
Configure the following parameters.

Table 1: Configuring Time Synchronization Parameters
Name	Description	Value
Time Sync Method	The synchronization method or protocol to use for synchronizing the time on the switch.	SNTP Default: NTP
Mode	The operating mode for connecting to a time server. The following modes are supported: Broadcast—The switch acquires time updates from the data that any time server broadcasts to the network. The switch uses the time data from the first server detected and ignores others. If the poll interval expires thrice without the switch acquiring a time update from the first server detected, the switch accepts a time update from the next server broadcast. NOTE: To use the Broadcast mode, the switch and the time server must be in the same subnetSubnet is the logical division of an IP network.. Also, the time server must be configured to broadcast time updates to the network broadcast address. Unicast—The switch acquires time updates from a specific server for time synchronization. This mode requires at least one server address to be configured in the Server Address field. DHCP—The switch attempts to acquire a time server IP address from the DHCP server. If the switch receives a server address, it polls the server for time updates according to the poll interval. If the switch does not receive a time server IP address, it cannot perform time synchronization updates. This mode is applicable only for SNTP. Disabled—Time synchronization is disabled. You cannot disable synchronization if NTP is selected.	SNTP Supported modes: Broadcast, Unicast, DHCP, and Disabled Default mode: DHCP NTP Supported modes: Broadcast, Unicast Default mode: Broadcast Default: DHCP
Server Address	IP address of the time server that the switch accesses for obtaining time synchronization updates. This field is applicable only when you select the Unicast mode for synchronization. You can configure a maximum of three time server IP addresses. When you add more than one IP address, the priority that the switch considers in selecting the IP address is the order in which you add the IP address. Therefore, the first IP address that you add will be priority 1, second IP address will be priority 2, and so on. You can delete the IP addresses by clicking the delete icon corresponding to the address. When more than one IP addresses are added, you must first delete the IP address you added last.	IPv4 address
Timezone	The time zone corresponding to the location of the switch.	Time zone selected from the drop-down.
Daylight Time Rule	The rule that the switch uses to adjust the time for Daylight Saving Time (DSTDaylight Saving Time. DST is also known as summer time that refers to the practice of advancing clocks, so that evenings have more daylight and mornings have less. Typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn. ). For information about the predefined and user-defined times, see Predefined DST Rules. When you select the User-defined option, you must configure the beginning and ending months and dates for DST changes in the Begin Month and Day and End Month and Day fields. All DST rules begin and end at 2 a.m. on the configured dates.	Alaska, Canada and Continental US, Middle Europe and Portugal, Southern Hemisphere, Western Europe, and User-defined.
Begin Month and Day	The beginning month and date for the user-defined DST changes. This field appears only when you select User-defined in the Daylight Time Rule field.	Month and date selected from the drop-down.
End Month and Day	The ending month and date for the user-defined DST changes. This field appears only when you select User-defined in the Daylight Time Rule field.	Month and date selected from the drop-down.

Click Save Settings.

Predefined DST Rules

Following are the details of the beginning and ending days for the predefined DST rules:

Predefined DST Rule Name	Description
Alaska	Begin DST at 2 a.m. on March 8. End DST at 2 a.m. on November 1.
Canada and Continental US
Middle Europe and Portugal	Begin DST at 2 a.m. on March 25. End DST at 2 a.m. on September 24.
Southern Hemisphere	Begin DST at 2 a.m. on October 25. End DST at 2 a.m. on March 1.
Western Europe	Begin DST at 2 a.m. on March 25. End DST at 2 a.m. on October 25.