Browse Prior Art Database

Known HTTP Proxy/Caching Problems (RFC3143)

IP.com Disclosure Number: IPCOM000005327D
Original Publication Date: 2001-Jun-01
Included in the Prior Art Database: 2001-Aug-21
Document File: 33 page(s) / 58K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

I. Cooper: AUTHOR [+2]

Abstract

This document catalogs a number of known problems with World Wide Web (WWW) (caching) proxies and cache servers. The goal of the document is to provide a discussion of the problems and proposed workarounds, and ultimately to improve conditions by illustrating problems. The construction of this document is a joint effort of the Web caching community.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 6% of the total text.

Network Working Group I. Cooper Request for Comments: 3143 Equinix, Inc. Category: Informational J. Dilley Akamai Technologies, Inc.

June 2001

Known HTTP Proxy/Caching Problems

Status of this Memo

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

Copyright Notice

Copyright (C) The Internet Society (2001). All Rights Reserved.

Abstract

This document catalogs a number of known problems with World Wide Web (WWW) (caching) proxies and cache servers. The goal of the document is to provide a discussion of the problems and proposed workarounds, and ultimately to improve conditions by illustrating problems. The construction of this document is a joint effort of the Web caching community.

Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1 Problem Template . . . . . . . . . . . . . . . . . . . . . . 2 2. Known Problems . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Known Specification Problems . . . . . . . . . . . . . . . . 5 2.1.1 Vary header is underspecified and/or misleading . . . . . . 5 2.1.2 Client Chaining Loses Valuable Length Meta-Data . . . . . . 9 2.2 Known Architectural Problems . . . . . . . . . . . . . . . . 10 2.2.1 Interception proxies break client cache directives . . . . . 10 2.2.2 Interception proxies prevent introduction of new HTTP

methods . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2.3 Interception proxies break IP address-based authentication . 12 2.2.4 Caching proxy peer selection in heterogeneous networks . . . 13 2.2.5 ICP Performance . . . . . . . . . . . . . . . . . . . . . . 15 2.2.6 Caching proxy meshes can break HTTP serialization of content 16 2.3 Known Implementation Problems . . . . . . . . . . . . . . . 17 2.3.1 User agent/proxy failover . . . . . . . . . . . . . . . . . 17 2.3.2 Some servers send bad Content-Length headers for files that

contain CR . . . . . . . . . . . . . . . . . . . . . . . 18

Cooper Dilley Informational [Page 1]

RFC 3143 Known HTTP Proxy/Caching Problems June 2001

3. Security Considerations . . . . . . . . . . . . . . . . . . 18 References . . . . . . . . . . . . . . . . . . . . . . . . . 19

Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 20 A. Archived Known Problems . . . . . . . . . . . . . . . . . . 21 A.1 Architectural . . . . . . . . . . . . . . . . . . . . . . . 21 A.1.1 Cannot specify multiple URIs for replicated resources . . . 21 A.1.2 Replica distance is unknown . . . . . . . . . . . . . . . . 22 A.1.3 Proxy resource location . . . . . . . . . . . . . . . . . . 23 A.2 Implementation . . . . . . . . . . . . . . . . . . . . . . . 23 A.2.1 Use of Cache-Control headers . . . . . . . . . . . . . . . . 23 A.2.2 Lack of HTTP/1.1 compliance for caching proxies . . . . . . 24 A.2.3 ETag support . . ...