If you are an organization with clients located across the globe, it would be beneficial to position your content in closer proximity to your clients. To do so, you can build your own Internet Content Delivery Network (ICDN). With an ICDN, you require two or more distributed data center locations, such as those illustrated in the Figure 4-3 and Figure 4-5, to share the traffic load from clients. For example, if your main data center is located in California but you have determined that 30 percent of your clients actually originate from Europe, it may be beneficial to replicate some critical services and deploy another data center somewhere in Europe. Figure 4-7 shows a simple ICDN.
Figure 4-7. An ICDN Network Topology
Alternatively, if you are a service provider, such as a web or application hosting provider, your clients may benefit from an ICDN. If so, you can develop an ICDN to replicate your client's content across geographic locations, not just your own content.
To achieve a distributed data center environment, you will learn content networking technologies such as Domain Name Service (DNS), Border Gateway Protocol (BGP), and Global Server Load Balancing (GSLB) in Chapter 12, "Exploring Global Server Load Balancing."
With ICDN, requesting clients perceive lower response times and cross-site redundancy is achieved in the event of the primary data center failing.
Numerous third-party ICDNs exist today to provide dedicated global ICDN services, such as Akamai and Digital Island. These companies have thousands of data centers worldwide, which are available to house surrogates of your content content. These ICDNs offer replication of static and even dynamic content. The benefit of outsourced ICDN services is that you do not require the initial capital expenditure and ongoing data center management costs to set up and manage your own global Internet CDN.