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Simple Hit-Metering and Usage-Limiting for HTTP (RFC2227) Disclosure Number: IPCOM000002785D
Original Publication Date: 1997-Oct-01
Included in the Prior Art Database: 2019-Feb-15
Document File: 37 page(s) / 52K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Mogul: AUTHOR [+1]

Related Documents

10.17487/RFC2227: DOI


This document proposes a simple extension to HTTP, using a new "Meter" header. [STANDARDS-TRACK]

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 7% of the total text.

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.


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."


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 com...