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A DNS-based Client Redirector for the Apache HTTP Server

Author: Michal Szymaniak
Source: Masters thesis, Vrije Universiteit, July 2002.


The client redirection problem is one of the most fundamental issues when developing a Content Delivery Network (CDN). This thesis discusses three known solutions and describes the implementation of one of them, which exploits a special DNS protocol implementation. The system consists of a special module for the Apache HTTP Server, which supports the basic functions of a typical DNS server. The module generates custom DNS responses based on network distance calculations according to the AS-path length metric. The Internet topology information required to compute the AS-path length metric is derived from BGP routing tables. Performance measurements prove that the overhead introduced by the network distance calculations is negligible in comparison to the overall DNS request-reply delay.

Keywords: Redirection, CDN, DNS, Apache, Autonomous Systems, BGP.


* The thesis, in gzipped Postscript (409,680 bytes).
* The thesis, in PDF (1,207,877 bytes).

See Also

* The Globule project implements the ideas described in this thesis.

Bibtex Entry

  author = 	 {Michal Szymaniak},
  title = 	 {A DNS-based Client Redirector for the Apache HTTP Server},
  school = 	 {Vrije Universiteit},
  address = 	 {Amsterdam, The Netherlands},
  year = 	 {2002},
  month = 	 jul
Last modified: Thu Feb 12 15:39:19 2004