Internet Web Replication and Caching Taxonomy
RFC 3040

Document Type RFC - Informational (January 2001; No errata)
Last updated 2013-03-02
Stream IETF
Formats plain text pdf html bibtex
Stream WG state (None)
Document shepherd No shepherd assigned
IESG IESG state RFC 3040 (Informational)
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)
Network Working Group                                          I. Cooper
Request for Comments: 3040                                 Equinix, Inc.
Category: Informational                                         I. Melve
                                                                 UNINETT
                                                            G. Tomlinson
                                                          CacheFlow Inc.
                                                            January 2001

             Internet Web Replication and Caching Taxonomy

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 memo specifies standard terminology and the taxonomy of web
   replication and caching infrastructure as deployed today.  It
   introduces standard concepts, and protocols used today within this
   application domain.  Currently deployed solutions employing these
   technologies are presented to establish a standard taxonomy.  Known
   problems with caching proxies are covered in the document titled
   "Known HTTP Proxy/Caching Problems", and are not part of this
   document.  This document presents open protocols and points to
   published material for each protocol.

Table of Contents

   1.      Introduction . . . . . . . . . . . . . . . . . . . . . . .  3
   2.      Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.1     Base Terms . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.2     First order derivative terms . . . . . . . . . . . . . . .  6
   2.3     Second order derivatives . . . . . . . . . . . . . . . . .  7
   2.4     Topological terms  . . . . . . . . . . . . . . . . . . . .  7
   2.5     Automatic use of proxies . . . . . . . . . . . . . . . . .  8
   3.      Distributed System Relationships . . . . . . . . . . . . .  9
   3.1     Replication Relationships  . . . . . . . . . . . . . . . .  9
   3.1.1   Client to Replica  . . . . . . . . . . . . . . . . . . . .  9
   3.1.2   Inter-Replica  . . . . . . . . . . . . . . . . . . . . . .  9
   3.2     Proxy Relationships  . . . . . . . . . . . . . . . . . . . 10
   3.2.1   Client to Non-Interception Proxy . . . . . . . . . . . . . 10

Cooper, et al.               Informational                      [Page 1]
RFC 3040      Internet Web Replication & Caching Taxonomy   January 2001

   3.2.2   Client to Surrogate to Origin Server . . . . . . . . . . . 10
   3.2.3   Inter-Proxy  . . . . . . . . . . . . . . . . . . . . . . . 11
   3.2.3.1 (Caching) Proxy Meshes . . . . . . . . . . . . . . . . . . 11
   3.2.3.2 (Caching) Proxy Arrays . . . . . . . . . . . . . . . . . . 12
   3.2.4   Network Element to Caching Proxy . . . . . . . . . . . . . 12
   4.      Replica Selection  . . . . . . . . . . . . . . . . . . . . 13
   4.1     Navigation Hyperlinks  . . . . . . . . . . . . . . . . . . 13
   4.2     Replica HTTP Redirection . . . . . . . . . . . . . . . . . 14
   4.3     DNS Redirection  . . . . . . . . . . . . . . . . . . . . . 14
   5.      Inter-Replica Communication  . . . . . . . . . . . . . . . 15
   5.1     Batch Driven Replication . . . . . . . . . . . . . . . . . 15
   5.2     Demand Driven Replication  . . . . . . . . . . . . . . . . 16
   5.3     Synchronized Replication . . . . . . . . . . . . . . . . . 16
   6.      User Agent to Proxy Configuration  . . . . . . . . . . . . 17
   6.1     Manual Proxy Configuration . . . . . . . . . . . . . . . . 17
   6.2     Proxy Auto Configuration (PAC) . . . . . . . . . . . . . . 17
   6.3     Cache Array Routing Protocol (CARP) v1.0 . . . . . . . . . 18
   6.4     Web Proxy Auto-Discovery Protocol (WPAD) . . . . . . . . . 18
   7.      Inter-Proxy Communication  . . . . . . . . . . . . . . . . 19
   7.1     Loosely coupled Inter-Proxy Communication  . . . . . . . . 19
   7.1.1   Internet Cache Protocol (ICP)  . . . . . . . . . . . . . . 19
   7.1.2   Hyper Text Caching Protocol  . . . . . . . . . . . . . . . 20
   7.1.3   Cache Digest . . . . . . . . . . . . . . . . . . . . . . . 21
   7.1.4   Cache Pre-filling  . . . . . . . . . . . . . . . . . . . . 22
   7.2     Tightly Coupled Inter-Cache Communication  . . . . . . . . 22
   7.2.1   Cache Array Routing Protocol (CARP) v1.0 . . . . . . . . . 22
   8.      Network Element Communication  . . . . . . . . . . . . . . 23
   8.1     Web Cache Control Protocol (WCCP)  . . . . . . . . . . . . 23
   8.2     Network Element Control Protocol (NECP)  . . . . . . . . . 24
   8.3     SOCKS  . . . . . . . . . . . . . . . . . . . . . . . . . . 25
   9.      Security Considerations  . . . . . . . . . . . . . . . . . 25
   9.1     Authentication . . . . . . . . . . . . . . . . . . . . . . 26
   9.1.1   Man in the middle attacks  . . . . . . . . . . . . . . . . 26
   9.1.2   Trusted third party  . . . . . . . . . . . . . . . . . . . 26
Show full document text