15.4. Request Distribution in CDNs
CDNs employ many CDN servers for content delivery. Large multi-ISP CDNs can have several thousand CDN servers. Once a request is delivered to its network as discussed in Section 15.2, the CDN must distribute this request to one of its servers. We considered a number of basic request-redirection mechanisms in Chapter 14. CDNs typically combine them in an attempt to gain the benefits of each. The goals of the resulting mechanism include allowing both wide-area and local-area request distribution and providing service to very high-volume Web sites. This section describes some combinations of the basic request-redirection mechanisms that can be used by a CDN.
15.4.1. DNS/Balancing Switch Redirection
Redirection ...
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