A DNS-based Client Redirector for the Apache HTTP Server
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.