What is Stratum?

In the world of NTP, stratum levels define the distance from the reference clock. A reference clock is a stratum-0 device that is assumed to be accurate and has little or no delay associated with it. The reference clock typically synchronizes to the correct time (UTC) using GPS transmissions, or other time signals such as GNSS, QZSS etc. Stratum-0 servers cannot be used on the network, instead, they are directly connected to computers which then operate as stratum-1 servers.

Stratum1 refers to the level of a time server in the Network Time Protocol (NTP) hierarchy. A
Stratum 1 server is directly connected to a highly accurate time source, such as:

Stratum 1 servers provide time to Stratum 2 servers, which in turn synchronize lower-stratum servers/devices.

Their operation ensures the distribution of synchronized time throughout the network.

Role in Network Time Protocol (NTP)

In an NTP hierarchy

  • Stratum 0 The actual time sources (like atomic clocks or GPS).
  • Stratum1 Servers that connect directly to Stratum 0 time sources.
  • Stratum2 and higher: Devices or servers that get time from Stratum 1 or other lower-stratum servers.

Using a Stratum 1 server ensures precise and reliable time synchronization across networks.

A stratum-2 server is connected to the stratum-1 server OVER A NETWORK PATH.  Thus, a stratum-2 server gets its time via NTP packet requests from a stratum-1 server.  A stratum-3 server gets its time via NTP packet requests from a stratum-2 server, and so on.

Stratum 1 Server Deployment

When deploying Stratum 1 servers, consider network topology, reliability of the reference clock, and security measures.

Use multiple Stratum 1 servers to ensure availability and reliability.

Continue down the line (Stratum 3, Stratum 4, etc.), each synchronizing with the level above.

Stratum 1 & 2 Server Deployment

NTP and Stratum 1 Servers: Essential for maintaining synchronized and accurate time across networks.

Impact: Proper time synchronization improves network efficiency, security, and reliability.

Master Clock Deployment

Display and distribute time.