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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: 2000-Sep-12
Document File: 8 page(s) / 22K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Mills: AUTHOR

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.

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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

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...