CONTENT DELIVERY NETWORKS

Content Delivery Networks

Content Delivery Networks

Introduction

A content delivery network or content distribution network (CDN) is a system of computers containing copies of data placed at diverse nodes of a network. When properly designed and implemented, a CDN can improve access to the data it caches by expanding access bandwidth and redundancy and reducing access latency. Data content kinds often cached in CDNs encompass web objects, downloadable objects (media files, software, documents), applications, immediate media streams, and database queries (Pascal Felber, 2009, pp.2061).

Although peer-to-peer (P2P) is not traditional CDN technology, it is increasingly utilised to deliver content to end users. P2P assertions reduced cost and effective distribution. Even though P2P really develops more traffic than traditional client-server CDNs for the for demonstration provider (because a gaze furthermore uploads data rather than of just downloading it) it's met by parties running content delivery/distribution services. The genuine strength of P2P shows when one has to distribute data in high demand, like the latest episode of a television show or some sort of software patch/update in short time span of time. One of the benefits of this is that the more people who download the (same) data, the more effective P2P is for the provider, slashing the cost of the transit charges that a CDN provider has to yield to their upstream IP transit providers (Pascal Felber, 2009, pp.2063).

Discussion

The complete network architecture comprises of several individual components, or infrastructures, whose purpose is to provide a service to the user community. An demonstration of an infrastructure constituent could be consolidated file servers, which act as repositories for user files and application data. These servers sit atop another constituent of the architecture: the routing and switching infrastructure. The foundation for network architecture lies in the routing and switching infrastructure, which provides transport for all other infrastructure components and their various forms of data (D. Carra, 2006, pp.121).

CDNs are considered "overlays" to the routing and swapping architecture as well, but they are exclusive to other infrastructures in that they have the proficiency to share characteristics of each of them. A CDN can bring together the functionality of file-access, caching, multimedia delivery and application processing -- while utilising the advanced policies of the routing and switching infrastructure to ensure survivability and guaranteed delivery. A CDN may have the proficiency to deliver this functionality, but the individual CDN components are key to producing it possible.

Figure 1: Architecture of a Content Delivery Network

Each site is hosted by a modest number of servers belonging to the collaborative CDN (typically in the order of a dozen servers). One of them is called the origin server. It contains the authoritative version of all documents of the site, and is responsible for distributing contents among other involved servers. The origin server normally pertains to the site's owner.

The origin server of a given site should normally be reachable by other servers at all times. However, as this server will not be assumed to be always available, it is helped out by any number of ...