CDN switching adds flexibility

Wide-area load balancers with content-delivery network switching technology let companies use public CDN services to extend global availability and content distribution.

Think of CDN switching as a bridge that organizations can extend to CDNs of their choice, on a pay-per-use basis. CDN switching lets organizations take advantage of shared public services, and lets them leverage those shared services when they wish.

CDN switching and wide-area load balancers create a more efficient, cost-effective use of global networks, ensures scalable content distribution, and provides end users with a better Web experience - one they will be willing to seek out and pay a premium for.

These two technologies also let organizations control the decision of which CDN or third party to peer - they can choose to utilize an alliance of CDN providers, a single provider, or multiple unaligned providers, depending on criteria such as price, geographic reach of the CDN and performance.

Organizations can also choose under which conditions or thresholds to utilize a CDN or third-party network, then easily and dynamically change the conditions, because they control the settings. For example, within the wide-area load balancer, organizations can select a setting that specifies that when a data center reaches a capacity of 10M bit/sec, the wide-area load balancer overflows all subsequent requests to a third-party network or CDN - until that threshold is no longer exceeded.

A content provider that has a television advertisement running during the Super Bowl broadcast would not want to spend money building new infrastructure to handle the associated one-time increase in traffic to its site. CDN switching would let the content provider create an overflow network and rent additional traffic capacity from the CDN. An overflow insurance "premium" would be paid in megabits per second. (That is, the content provider might normally pay a certain amount of money per megabit per to serve content from its own infrastructure, but pay a premium when it expects the origin site not to be able to handle traffic demands.)

CDN switching, along with a wide-area traffic manager, can combine client attributes with IP addresses, enabling traffic management decisions to include the client's continent, country, state or city. The traffic managers can direct traffic from specific regions to the content provider's network, to be served at a lower bandwidth cost - or to various CDNs, to be served at higher premium rates in exchange for a better presence in certain regions. For example, content providers can send 30% of their traffic from the U.K. to Digital Island and 50% of their traffic from the western U. S. to Akamai, and serve the rest of their traffic from less expensive infrastructure. CDN switching provides this detailed control, letting content providers spend their dollars wisely, build where it is cheaper to build, and outsource the rest.

Similarly, a content provider could extend its domestic services to an international market, again without building new infrastructure. CDN switching allows rules to be set that identify traffic originating from an international market. Content providers could easily redirect those requests to a content-delivery service that could reliably serve those geographic regions.

CDN switching technology can also monitor all network resources for performance criteria. When that criteria is exceeded, the wide-area traffic manager can kick in and dynamically redirect requests to a CDN service until the criteria returns to a nominal state. This gives content providers traffic overflow capabilities and lets them pay only for actual bandwidth used.

Finally, a wide-area load balancer with CDN switching gives content providers the flexibility to negotiate different types of agreements with different service providers, and lets them send a proportionate number of requests to each service provider based on individually established pricing models.

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Skene is a product development manager at F5 Networks in Seattle. He can be reached at b.skene@f5.com.