A conventional content delivery network (CDN) includes, among other things, a set of content servers and a set of CDN request handlers. The content servers typically store and provide content to clients on behalf of the hosted domains (e.g., provides web content to computers running browser applications in response to HTTP requests). The CDN request handlers, which are commonly referred to as content routers, typically provide Internet addresses to enable the clients to properly identify particular content servers within the CDN. Further details of how content routers provide such Internet addresses will now be provided.
Generally, when a CDN client (i.e., a web browser) wishes to obtain content from a hosted domain, the client begins by sending a Domain Name System (DNS) request for the desired domain name to a DNS proxy server. The DNS proxy server (perhaps through other DNS proxy servers) communicates with content router on behalf of the client in order to obtain an IP address of a content delivery site of the hosted domain. In particular, the DNS proxy server sends, to the content router, a DNS request containing the Internet Protocol (IP) address of the DNS proxy server but not containing the IP address of the client. The content router typically responds to the DNS request by selecting and returning the IP address of a content delivery site that is closest to the DNS proxy server. Accordingly, in this conventional approach, when clients are near the DNS proxy server from a network perspective, the content router selects content delivery sites which are close to the clients.