NTP Over Anycast: The Easy Way to Sync Clients and Servers

What Is NTP Over Anycast?

NTP (Network Time Protocol) over Anycast mode is a software technology that allows two (or more) NTP servers to sync clients via a single IP address.

NTP is a packet network-based synchronization protocol to sync a client clock to a network master clock.

Anycast is a network routing protocol where messages are routed to one of a group of potential receivers via a single Anycast address, thus avoiding the need to configure every client individually.

NTP over Anycast, available in both SecureSync and NetClock, is a combination of the two concepts, allowing them to:

  • Associate one of their network ports to an Anycast IP address
  • Remove themselves as an available time source if the reference is lost or degraded, or vice versa

Though NTP clients typically need to be individually configured with the IP address(es) they are to sync with – even when using NTP over Anycast mode – this mode allows the clients to be configured with one address instead of two, and lets the closest available time server to respond to the request.

How It Works

  • Configure an Anycast IP address to any Orolia network interface.
  • NTP server responds to client requests as directed by the Open Shortest Path First (OSPF) routing protocol so long as the time server is in sync.
  • NTP server becomes “unavailable” if the time server goes out of sync or a problem with its reference is detected. Client requests are directed to the “next-nearest” server, which is also configured with the NTP over Anycast address.
  • NTP server is automatically made available when synchronized.

When to Use NTP Over Anycast

Configuring NTP clients for mission-critical timing using NTP servers with static IP addresses can be problematic for large deployments across several network and geographic boundaries. Referencing an NTP server by hostname with existing DNS infrastructure can help, but still requires a lot of configuration. Starting with Version 4, the NTP daemon offers a Manycast feature that allows a client to automatically discover and configure a group of NTP servers. But, for Anycast-enabled networks, the ability to route NTP requests to several potential servers via a single IP address, without any specific client configuration, offers the simplest, most reliable, most scalable approach.

Benefits to You

  • Reduce latency, increase availability, improve scalability of NTP deployments.
  • Simplify the management of a reliable wide-area NTP deployment with redundant stratum-1 servers.
  • Leverage the ability of a “smart” NTP server for a simple NTP client implementation.
NTP over Anycast scenarios

How to Get NTP Over Anycast

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