We are going to discuss Azure Content Delivery Network today. It’s important to understand the need of using CDN and how it works.
Azure CDN is used to cache static web content for better performance and user experience. It’s actually distributes the user requests and send requests to Edge Servers rather sending all request to Origin Server. Using CDN we can get maximum throughput to deliver content. Read static content from CDN and get dynamic content from your virtual machine.
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We have three Azure CDN Products which we can decide based on features provided for each product type.
– Standard Akamai
– Standard Verizon
– Premium Verizon
So how the CDN works?
Let’s understand Point Of Presence and POP locations for Azure CDN.
Point of presence (POP) is the point at which two or more different networks or communication devices make a connection with each other to establish a connection with the Internet.
Please refer below links for Azure POP Locations.
Azure CDN from Verizon and Azure CDN from Akamai.
New Azure CDN POP locations.
Now let’s talk about use of Azure CDN.
DNS routes user requests to the best performing POP edge server and the location which is geographically closest to the user. We discussed Edge server keeps the file in cache but if the files are not available in Edge Server and the request will be sent to Origin. The Origin further returns the file to edge server. The Edge Server further caches the file (For future request) and return the file to the requestor/user.
Now when another user request for the same file, Azure CDN will return the file request from Edge server which is already cached.
The default Time-to-live (TTL) is 7 days. We can specify the TTL in Origin.