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Application of Internet Cache Protocol (ICP), version 2 (RFC2187)

IP.com Disclosure Number: IPCOM000002746D
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 19 page(s) / 48K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Wessels: AUTHOR [+2]

Abstract

This document describes the application of ICPv2 (Internet Cache Protocol version 2, RFC2186) to Web caching. ICPv2 is a lightweight message format used for communication among Web caches. Several independent caching implementations now use ICP[3,5], making it important to codify the existing practical uses of ICP for those trying to implement, deploy, and extend its use.

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

Network Working Group D. Wessels

Request for Comments: 2187 K. Claffy

Category: Informational National Laboratory for Applied

Network Research/UCSD

September 1997

Application of Internet Cache Protocol (ICP), version 2

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

Abstract

This document describes the application of ICPv2 (Internet Cache

Protocol version 2, RFC2186) to Web caching. ICPv2 is a lightweight

message format used for communication among Web caches. Several

independent caching implementations now use ICP[3,5], making it

important to codify the existing practical uses of ICP for those

trying to implement, deploy, and extend its use.

ICP queries and replies refer to the existence of URLs (or objects)

in neighbor caches. Caches exchange ICP messages and use the

gathered information to select the most appropriate location from

which to retrieve an object. A companion document (RFC2186)

describes the format and syntax of the protocol itself. In this

document we focus on issues of ICP deployment, efficiency, security,

and interaction with other aspects of Web traffic behavior.

Table of Contents

1. Introduction................................................. 2

2. Web Cache Hierarchies........................................ 3

3. What is the Added Value of ICP?.............................. 5

4. Example Configuration of ICP Hierarchy....................... 5

4.1. Configuring the `proxy.customer.org' cache................. 6

4.2. Configuring the `cache.isp.com' cache...................... 6

5. Applying the Protocol........................................ 7

5.1. Sending ICP Queries........................................ 8

5.2. Receiving ICP Queries and Sending Replies.................. 10

5.3. Receiving ICP Replies...................................... 11

5.4. ICP Options................................................ 13

6. Firewalls.................................................... 14

7. Multicast.................................................... 14

8. Lessons Learned.............................................. 16

8.1. Differences Between ICP and HTTP........................... 16

8.2. Parents, Siblings, Hits and Misses......................... 16

8.3. Different Roles of ICP..................................... 17

8.4. Protocol Design Flaws of ICPv2............................. 17

9. Security Considerations...................................... 18

9.1. Inserting Bogus ICP Queries................................ 19

9.2. Inserting Bogus ICP Replies................................