RFC 1361 (rfc1361) - Page 1 of 10

Simple Network Time Protocol (SNTP)

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Network Working Group                                           D. Mills
Request for Comments: 1361                        University of Delaware
                                                             August 1992


                  Simple Network Time Protocol (SNTP)

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard.  Distribution of this memo is
   unlimited.

Abstract

   This memorandum describes the Simple Network Time Protocol (SNTP),
   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. It involves no change to the
   current or previous NTP specification versions or known
   implementations, but rather a clarification of certain design
   features of NTP which allow operation in a simple, stateless RPC mode
   with accuracy and reliability expectations similar to the UDP/TIME
   protocol described in RFC-868.

   This memorandum does not obsolete or update any RFC. A working
   knowledge of RFC-1305 is not required for an implementation of SNTP.

1. Introduction

   The Network Time Protocol (NTP) specified in RFC-1305 [MIL92] is used
   to synchronize computer clocks in the global Internet. It provides
   comprehensive mechanisms to access national time and frequency
   dissemination services, organize the time-synchronization subnet and
   adjust the local clock in each participating subnet peer. In most
   places of the Internet of today, NTP provides accuracies of 1-50 ms,
   depending on the jitter characteristics of the synchronization source
   and network paths.

   RFC-1305 specifies the NTP protocol machine in terms of events,
   states, transition functions and actions and, in addition, optional
   algorithms to improve the timekeeping quality and mitigate among
   several, possibly faulty, synchronization sources. To achieve
   accuracies in the low milliseconds over paths spanning major portions
   of the Internet of today, these intricate algorithms, or their
   functional equivalents, are necessary. However, in many cases
   accuracies of this order are not required and something less, perhaps



Mills
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