Good piece of information on the functionality that should be considered in a content delivery network - http://blog.streamingmedia.com/the_business_of_online_vi/2011/06/how-mobile-acceleration-works-an-inside-look-at-cotendos-newly-announced-service.html
Means of achieving the optimization in different layers:
- Network layer: Dynamic site acceleration (DSA) - a combination of improved TCP algorithms and route optimization along with more advanced DNS mapping to speed up transport of packets at the network layer (http://blog.streamingmedia.com/the_business_of_online_vi/2010/10/how-dynamic-site-acceleration-works-what-akamai-and-cotendo-offer.html)
- Content acceleration – Adaptive image compression and caching various image sizes close to the network edge; also real-time decisions with regards to device type and network condition on content serving, caching and delivery to accommodate the specific conditions of each request. I believe licensed CDN (LCDN) is one of the variant of content acceleration wherein optimization of video content takes place inside the carrier network for mobile video content owners and it uses network condition to dynamically transrate the content that is being rendered
- App acceleration – Serving the right social network content, mobile commerce, mobile ads and coupons and location specific data all require some degree of logic e.g., let a mobile ad network push to the edge ads that are close to an end user’s location and then serve them the correct ads subsequently without requiring additional content calls back to the origin server