Deploying Application Request Routing in CDN

Can anyone explain the steps for deploying ARR in CDN? I already read the guide here

I don't understand where the cache servers are. When w开发者_如何学Ce purchase a server from the CDN company it becames the origin server. Do we need additional servers? And where are we using the parent cache nodes?

Thanks in advance

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This guide describes how to use ARR and IIS to set up your own CDN. So it assumes you set up your own servers for the parent and child nodes. This is not very common though, usually you pay another company to use their CDN, e.g. Windows Azure CDN.

The origin server is the web server having the original or master copy of the website. It's the one website that you maintain and update. The child nodes are the servers that are accessed by the browsers of your visitors. If a child node does not have a copy of the requested file, it will request it from it's parent nodes. If the parent node doesn't have it either, it will request it from the origin server. The parent and child nodes will cache the file in order to serve it up more quickly on subsequent request.

Where exactly each server is depends on how you set up the CDN. But commonly groups of child nodes are hosted on geographically different places around the world. Each group of child nodes has one parent node handling all request from all childs at that location. If the parent node doesn't have the file in it's cache, it will request it from the origin server. So the origin server typically only receives requests from the parent nodes.