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14. Simple Network Time Protocol (SNTP)

Simple Network Time Protocol (SNTPv4) is a subset of NTP for primary servers and clients that don't need full mitigation algorithms. SNTP is fully interoperable with NTP and can be intermixed in NTP subnets.

Use Cases​

SNTP suitable for:

  • Primary servers with single reference clock
  • Clients with single upstream server and no dependent clients

Full NTP suitable for:

  • Secondary servers with multiple upstream servers
  • Servers with multiple downstream servers/clients

SNTP Primary Server​

Implements on-wire protocol from Section 8. Has no upstream servers except single reference clock. Upon receiving client request, constructs reply packet with system variables mapped to packet fields.

SNTP Client​

Has single server and no dependent clients. Simplest approach uses only server's transmit timestamp. Full on-wire protocol implementation encouraged due to minimal additional complexity.

Interoperability​

SNTP and NTP servers/clients are completely interoperable. Main difference: SNTP doesn't implement mitigation algorithms (selection, cluster, combine).

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