Content delivery networks: the new quality stakes for Web sites

These new networks in charge of optimising content delivery from servers to Web sites have been on the roll for quite a while now.

By saving two seconds here, three seconds there, these technologies ensure Web pages to load faster and therefore increase the chances that a user will stay at a Web site.

Surveys show that Internet users are not ready to wait any more than 8 seconds for pages to load. When you add up the marketing expenses that have to be spent to generate traffic on a Web site, you might be able to understand better why you need to offer faster loading times if you do not want to waste your marketing investments… not to mention the eventual damage it can do to your image!

The marketing firm Frost & Sullivan defines these new networks as a complete solution for distributing and delivering Web-based content closer to end users.

These solutions use three different levels of implementation to reach such aim:

• Bypass Internet traffic jams.
  
  
• Optimise bandwidth use.
  
  
• Reduce operating costs.

At a time when Web sites have no choice but multiply services in order to establish customer loyalty in the BtoB but also in the BtoC sectors, there is no doubt that most of them will soon resort to these CDNs (Content delivery networks).

Indeed, most of these new transactional eServices consume large quantities of bandwidth and yet, operators no longer prove able to meet user's expectancies which leads to a constant worsening of its performances.

What's more, these services require a high quality level as far as data exchange is concerned and the Internet does not prove able to offer it just yet (for instance: video on demand). This mostly explains why business models based on a fast generalization of high bandwidth (web TV, e-learning, etc…) are nothing but a failure.

CDN networks are based on two elements: wide area traffic management and caching.

In concrete terms, wide area traffic manager aims at adding intelligence to standard DNS services in order to direct content requests to the most optimal site. These algorithms mainly take into account the server's geographic origin as well as network topology.

What's more, these tools make it possible to set rules in order to have highly available Web sites.

For instance, a request that comes from such and such region in the world has be sent to a given data centre and if the latter is too busy, you then have to direct it to another specific data centre. This is how it is now easier to predict the way requests are directed. These new DNS services are based on the latest BIND technology, still in its early stages, that was originally developed at the University of Berkeley.

As for the cache functions (which are best known), they aim at storing Web sites content on servers peppered throughout the world so that data has a shorter way to go to get to one that is closer than if all data was kept on a single centre. These caches are devised in such a way that information is always refreshed, thus ensuring the integrity of all cache servers content (this is a key element for news Web sites since their content keeps on changing).

As we can see with these two elements that offer CDNs solutions, it is once again experience that will make the distinction between web sites, between those who will proceed by trial and error and will thus acquire an internal expertise, and those who will fall in every single operators' trap. Indeed, the benefits gained from these solutions will depend on how sharply designed these managing tools for DNS and caches happen to be. Concrete experience alone can bring this knowledge to the sites.

Source : Webtechniques