RFC 2030 (rfc2030) - Page 1 of 18
Simple Network Time Protocol (SNTP) Version 4 for IPv4, IPv6 and OSI
Alternative Format: Original Text Document
Network Working Group D. Mills
Request for Comments: 2030 University of Delaware
Obsoletes: 1769 October 1996
Category: Informational
Simple Network Time Protocol (SNTP) Version 4
for IPv4, IPv6 and OSI
Status of this Memo
This memo provides information for the Internet community. This memo
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
Abstract
This memorandum describes the Simple Network Time Protocol (SNTP)
Version 4, which is an adaptation of the Network Time Protocol (NTP)
used to synchronize computer clocks in the Internet. SNTP can be used
when the ultimate performance of the full NTP implementation
described in RFC-1305 is not needed or justified. When operating with
current and previous NTP and SNTP versions, SNTP Version 4 involves
no changes to the NTP specification or known implementations, but
rather a clarification of certain design features of NTP which allow
operation in a simple, stateless remote-procedure call (RPC) mode
with accuracy and reliability expectations similar to the UDP/TIME
protocol described in RFC-868.
The only significant protocol change in SNTP Version 4 over previous
versions of NTP and SNTP is a modified header interpretation to
accommodate Internet Protocol Version 6 (IPv6) [DEE96] and OSI
[COL94] addressing. However, SNTP Version 4 includes certain optional
extensions to the basic Version 3 model, including an anycast mode
and an authentication scheme designed specifically for multicast and
anycast modes. While the anycast mode extension is described in this
document, the authentication scheme extension will be described in
another document to be published later. Until such time that a
definitive specification is published, these extensions should be
considered provisional.
This memorandum obsoletes RFC-1769, which describes SNTP Version 3.
Its purpose is to correct certain inconsistencies in the previous
document and to clarify header formats and protocol operations for
current NTP Version 3 (IPv4) and proposed NTP Version 4 (IPv6 and
OSI), which are also used for SNTP. A working knowledge of the NTP
Version 3 specification RFC-1305 is not required for an
implementation of SNTP.
Mills Informational