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Simple Network Time Protocol (SNTP) (RFC1361)

IP.com Disclosure Number: IPCOM000002185D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2019-Feb-11
Document File: 10 page(s) / 13K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Mills: AUTHOR

Related Documents

10.17487/RFC1361: DOI

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. This memorandum does not obsolete or update any RFC. This memo provides information for the Internet community. It does not specify an Internet standard. Discussion of the standardization process and the RFC document series is presented first, followed by an explanation of the terms. Sections 6.2 - 6.9 contain the lists of protocols in each stage of standardization. Finally come pointers to references and contacts for further information. [STANDARDS-TRACK]

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 14% of the total text.

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 [Page 1]

RFC 1361 SNTP August 1992

in the order of one second, is sufficient. In such cases simpler protocols such as the Time Protocol [POS83], have been used for this purpose. These protocols usually involve a remote-procedure call (RPC) exchange where the client requests the time of day and the server returns it in seconds past some known reference epoch.

NTP is designed for use by clients and servers with a wide range of capabilities and over a wide range of network delays and jitter characteristics. Most members of the Internet NTP synchronization subnet of today use software packages including the full suite of NTP options and algorithms, which are relatively complex, real-time applications. While the software has been ported to a wide variety of hardware platforms ranging from supercomputers to personal computers, its sheer size and complexity is not appropriate for many applications....

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