NCC - Auto Provision NTP Server Settings

Zyxel_Claudia

As part of the continuous improvements in Nebula 19.00, Zyxel Networks has introduced an enhanced mechanism for auto-provisioning NTP server settings. This upgrade brings better reliability, smarter load balancing, and improved time synchronization handling across Nebula-managed devices.

Here’s everything you need to know about this new feature.

Background: Why Improve NTP Server Handling?

Previously, some users experienced issues where devices failed to synchronize with NTP servers. One specific case involved an ISP in the specific country that blocked access to a popular NTP server, causing synchronization failures.

Additionally, when too many cloud-managed devices tried to connect to the same NTP server simultaneously — especially during recovery or initial setup — it often caused short bursts of high load and response delays.

To address these problems, Zyxel Networks made important adjustments:

• Devices must have backup NTP servers available.
• Devices must be randomly assigned NTP servers to enable load sharing.

New Auto-Provision Behavior: Switches and APs

For Switches:

• Default Setting:Switches are now provisioned automatically with three NTP servers.
  • NTP Server 1 and 2: Automatically managed and assigned by Nebula Control Center (NCC) for load sharing.
  • NTP Server 3: User-configurable — administrators can define their own preferred NTP server here.

For Access Points (APs):

• NTP Server 1: Fully user-configurable and retained even after reconnection.
• NTP Server 2: Automatically updated by Nebula Control Center for backup and load sharing purposes.
• NTP Servers 3, 4, and 5: System-level defaults used purely for backup. These are not visible or modifiable by users.

Behavior During Device Connection or Reconnection

NTP updates when a device (Switch or AP) connects or reconnects to Nebula:

• Switches:
  • NTP 1 and 2 are re-provisioned by NCC.
  • NTP 3 retains the user’s original setting.
• Access Points:
  • NTP 1 retains the user’s configured server.
  • NTP 2 is updated by NCC.
  • NTP 3-5 remain unchanged (backup-only, system-managed).

Load Sharing Mechanism: How It Works

Nebula’s NTP load sharing strategy ensures not all devices hit the same NTP server simultaneously:

• Randomized Assignment: NCC provisions different NTP servers like “pool.ntp.org” or “time.google.com” randomly across different devices.
• Example:
  • Switch A might have pool.ntp.org as NTP Server 1.
  • Switch B might have time.google.com instead.
  • APs might show a different combination based on user input and system provisioning.

This reduces the risk of overloading any single NTP server, ensuring smoother and faster time synchronization across large deployments.