Simple Hit-Metering and Usage-Limiting for HTTP
RFC 2227
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RFC - Proposed Standard
(October 1997; No errata)
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Authors |
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Jeffrey Mogul
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Paul Leach
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Last updated |
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2013-03-02
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IETF
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plain text
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bibtex
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(None)
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No shepherd assigned
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IESG |
IESG state |
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RFC 2227 (Proposed Standard)
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Consensus Boilerplate |
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Unknown
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Responsible AD |
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(None)
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(None)
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Network Working Group J. Mogul
Request for Comments: 2227 DECWRL
Category: Standards Track P. Leach
Microsoft
October 1997
Simple Hit-Metering and Usage-Limiting for HTTP
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1997). All Rights Reserved.
ABSTRACT
This document proposes a simple extension to HTTP, using a new
"Meter" header, which permits a limited form of demographic
information (colloquially called "hit-counts") to be reported by
caches to origin servers, in a more efficient manner than the
"cache-busting" techniques currently used. It also permits an origin
server to control the number of times a cache uses a cached response,
and outlines a technique that origin servers can use to capture
referral information without "cache-busting."
TABLE OF CONTENTS
1 Introduction 2
1.1 Goals, non-goals, and limitations 3
1.2 Brief summary of the design 4
1.3 Terminology 5
2 Overview 5
2.1 Discussion 7
3 Design concepts 8
3.1 Implementation of the "metering subtree" 8
3.2 Format of the Meter header 10
3.3 Negotiation of hit-metering and usage-limiting 10
3.4 Transmission of usage reports 14
3.5 When to send usage reports 15
3.6 Subdivision of usage-limits 16
Mogul & Leach Standards Track [Page 1]
RFC 2227 Hit-Metering and Usage-Limiting October 1997
4 Analysis 17
4.1 Approximation accuracy for counting users 18
4.2 What about "Network Computers"? 19
4.3 Critical-path delay analysis 19
5 Specification 20
5.1 Specification of Meter header and directives 20
5.2 Abbreviations for Meter directives 23
5.3 Counting rules 24
5.3.1 Counting rules for hit-metering 24
5.3.2 Counting rules for usage-limiting 25
5.3.3 Equivalent algorithms are allowed 26
5.4 Counting rules: interaction with Range requests 27
5.5 Implementation by non-caching proxies 27
5.6 Implementation by cooperating caches 28
6 Examples 28
6.1 Example of a complete set of exchanges 28
6.2 Protecting against HTTP/1.0 proxies 30
6.3 More elaborate examples 30
7 Interactions with content negotiation 31
7.1 Treatment of responses carrying a Vary header 31
7.2 Interaction with Transparent Content Negotiation 32
8 A Note on Capturing Referrals 32
9 Alternative proposals 33
10 Security Considerations 34
11 Acknowledgments 35
12 References 35
13 Authors' Addresses 36
14 Full Copyright Statement 37
1 Introduction
For a variety of reasons, content providers want to be able to
collect information on the frequency with which their content is
accessed. This desire leads to some of the "cache-busting" done by
existing servers. ("Cache-busting" is the use by servers of
techniques intended to prevent caching of responses; it is unknown
exactly how common this is.) This kind of cache-busting is done not
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