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Cisco SD-WAN
Product Documentation
Viptela Documentation


You can use the NTP template for all Viptela devices.

Configure network time protocol (NTP) servers on your Viptela devices in order to synchronize time across all devices in the Viptela overlay network. You can configure up to four NTP servers, and they must all be located or reachable in the same VPN.

Other devices are allowed to ask a Viptela device for the time, but no devices are allowed to use the Viptela device as an NTP server.

To configure NTP using vManage templates:

  1. Create an NTP feature template to configure NTP parameters, as described in this article.
  2. Configure the timezone in the System template. See the Configuration ► Templates ► System help topic.
  3. Create a device template that incorporates the NTP feature template. See the Configuration ► Templates help file.​

Navigate to the Template Screen

  1. In vManage NMS, select the Configuration ► Templates screen.
  2. From the Templates title bar, select Feature.
  3. Click Add Template.
  4. In the left pane, select one or more devices. The right pane displays the available templates for the selected devices.
  5. Select the NTP template.

The right pane displays the NTP template form:

  • The top of the form contains fields for naming the template.
  • The bottom contains fields for defining parameters applicable to that template.
  • A drop-down menu to the left of each parameter field defines the scope of the parameter. When you first open a feature template form, for each parameter that has a default value, the scope is set to Default. To edit a parameter field, change the scope to Global or Device Specific. Note that if a parameter's scope is Device Specific, you cannot enter a value for it in the feature template. Instead, you enter a value when you attach the template to a device.
  • A plus sign (+) is displayed to the right when you can add multiple entries for the same parameter.

Minimum NTP Server Configuration

The following parameters are required (unless otherwise indicated) to configure an NTP. Select the Server tab and click the plus sign (+):

Step Parameter Name Description
 1. Template Name Enter a name for the template. It can be up to 128 characters and can contain only alphanumeric characters.
 2. Description (Template) Enter a description of the template. It can be up to 2048 characters and can contain only alphanumeric characters.
 3. Hostname or IP Address Enter the IP address of an NTP server or of a DNS server that knows how to reach the NTP server.
 4. Authentication Key Specify the MD5 key associated with the NTP server, to enable MD5 authentication. For the key to work, you must mark it as trusted in the Trusted field of the Authentication tab (discussed below).
 5. VPN

Enter the ID for the VPN to use to reach the NTP server or the VPN in which the NTP server is located. If you configure multiple NTP servers, they must all be located or reachable in the same VPN.

Range: 0 through 65530

 6. Version Enter the version number of the NTP protocol software.
Range: 1 through 4
Default: 4
 7. Source Interface (optional) Enter the name of a specific interface to use for outgoing NTP packets. The interface must be located in the same VPN as the NTP server. If it is not, the configuration is ignored.
 8. Prefer (optional) Click On if multiple NTP servers are at the same stratum level and you want one to be preferred. For servers at different stratum levels, the software chooses the one with the highest stratum level.
 9. Authentication Set up any authentication required by the NTP servers, as discussed below.
 10. Save Click Save to save the feature template.

To add another NTP server, click the plus sign (+). You can configure up to four NTP servers. The software uses the server at the highest stratum level.

To delete an NTP server, click the trash icon to the right of the entry.

CLI equivalent:

  ​  server (dns-server-address | ip-address)
      key key-id
      source-interface interface-name
  ​    version number  ​    
      vpn vpn-id

Configure NTP Authentication

To configure authentication keys used to authenticate the NTP servers, select the Authentication tab:

Parameter Name Description
Trusted Click Trusted and enter the MD5 authentication key to designate the key as trustworthy. To associate this key with a server, enter it in the Authentication key field on the Server tab.

Click Authentication for each key, and enter the following values:

  • Authentication Key—Enter an MD5 key ID. It can be a number from 1 through 65535.
  • Authentication Value—Enter either a cleartext key or an AES-encrypted key.

CLI equivalent:

      authentication key-id md5 md5-key
      trusted key-id

Release Information

Introduced in vManage NMS in Release 15.2.

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