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What and Why of CDN

What is CDN? CDN is short for Content Delivery Network. A CDN in simple terms is a collection of servers that are spread across the globe. In other words, a CDN is a network of servers in which each request will go to the closest server. Why Do We Need CDN? For any web application, data can be categorized into either static or dynamic content. Dynamic content is the one which generally comes from a database. Static content is the one like CSS, images, JavaScript, flash files, video files, etc. Now one may ask, how are requests served when a user enters an URL in the browser? Interesting… let’s take a look at it. Before knowing a CDN and its usage, it is very important to understand this process. How is a Web Page Served? When a client requests any URL, let’s say www.google.com in the browser, there is a server configured to listen to any request that comes in for www.google.com . A server in turn performs some computations and sends raw HTML back to the client. Raw HTML

Overview of CDN

CDN (Content Delivery Network) A computer network which has multiple copies of data stored at different points of the network.   The end user connected to a CDN will access the data from the nearest server (middle) instead of connecting to a Central server.   Few of the applications include media distribution, multiplayer gaming, and distance learning.   The end user can be a wired or wireless unit, which tries to access the content. The middle servers (or several servers forming a cluster) store the images of the content from the central (main) server. They are located at the edge of the ISP network and may be geographically separated from each other. Elements of CDN Request: A request for a specific content (for e.g. a webpage) is made from the End user, which is redirected to the nearest image server. This is done by the use of a protocol known as Web Cache Communication Protocol (WCCP).   Distribution: Once the request is received, a distribution element