RFC 3568 (rfc3568) - Page 1 of 19
Known Content Network (CN) Request-Routing Mechanisms
Alternative Format: Original Text Document
Network Working Group A. Barbir
Request for Comments: 3568 Nortel Networks
Category: Informational B. Cain
Storigen Systems
R. Nair
Consultant
O. Spatscheck
AT&T
July 2003
Known Content Network (CN) Request-Routing Mechanisms
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 (2003). All Rights Reserved.
Abstract
This document presents a summary of Request-Routing techniques that
are used to direct client requests to surrogates based on various
policies and a possible set of metrics. The document covers
techniques that were commonly used in the industry on or before
December 2000. In this memo, the term Request-Routing represents
techniques that is commonly called content routing or content
redirection. In principle, Request-Routing techniques can be
classified under: DNS Request-Routing, Transport-layer
Request-Routing, and Application-layer Request-Routing.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. DNS based Request-Routing Mechanisms . . . . . . . . . . . . 3
2.1. Single Reply . . . . . . . . . . . . . . . . . . . . . 3
2.2. Multiple Replies . . . . . . . . . . . . . . . . . . . 3
2.3. Multi-Level Resolution . . . . . . . . . . . . . . . . 4
2.3.1. NS Redirection . . . . . . . . . . . . . . . . 4
2.3.2. CNAME Redirection. . . . . . . . . . . . . . . 5
2.4. Anycast. . . . . . . . . . . . . . . . . . . . . . . . 5
2.5. Object Encoding. . . . . . . . . . . . . . . . . . . . 6
2.6. DNS Request-Routing Limitations. . . . . . . . . . . . 6
3. Transport-Layer Request-Routing . . . . . . . . . . . . . . 7
Barbir, et al. Informational