A Survey on Content Delivery Network Architecture Features And Their Benefits

With the explosive increase in internet contents, the internet usage has shifted from host-to-host model to content dissemination model, e.g. video content accounts for the majority of Internet traffics. Content delivery networks (CDNs) can be seen as a solution to the problem and is one of the most important components of internet today. ISPs, content providers and other third parties have already deployed CDNs to improve user experience. In order to maximize the bandwidth, improve accessibility, maintain correctness through the content replication and bringing the content as close as possible to the clients system CDN’s are proposed. CDN's web content is distributed to cache servers located to users resulting in fast, reliable applications and web services for the users. CDN maintains multiple point of presence (POP). As the Gateway network users and contents, POP's provide several key features for CDN’s and they will be discussed in the paper. As the CDN architecture is evolving through the adoption of emerging paradigms, we make a survey on two general approaches to building CDN’s one is the overlay model which replicates content to thousands of servers worldwide and another approach is network model which deploys code to routers and switches so that they can recognize specific application types and make forward decisions based of predefined policies. The benefit of each model has also been discussed. Layered architecture of CDN has been discussed in detail. Finally, we discuss potential avenues for further research aspects in CDNs.