What is Azure Content Delivery Network ?
Azure Content Delivery Network
Azure Content Delivery Network ( CDN ) can be defined as a distributed network of servers that can efficiently deliver content to end-users, moreover, CDN store cached content on edge servers in point of presence locations that are close to end-users, to minimize latency. CDN offers developers a global platform for high bandwidth content to users by caching their content at strategically placed physical nodes across the world.
The benefits of Azure Content Delivery Network are:
- The user request is distributed and served directly from edge servers, in such a way that less traffic is sent to the origin or main server.
- Large scaling to better handle instantaneous high loads.
- Better performance ad improved user experience for end-users.
The limitations are as follows:
- The number of custom domains that can be mapped to the endpoint.
- The number of profiles can be made.
- The number of endpoints that can be made in endpoints.
Azure CDN features:
- Geo Filtering
- File Compression
- Https Custom Domain Support
- CDN caching rules.
- Dynamic site acceleration
- Azure Diagnostic logs.
How it works:
A user (Steve) requests a file (also called an asset) by using a URL with a special domain name, such as <endpoint name>.azureedge.net. This name can be an endpoint hostname or a custom domain. The DNS routes the request to the best performing POP location, which is usually the POP that is geographically closest to the user.
If no edge servers in the POP have the file in their cache, the POP requests the file from the origin server. The origin server can be an Azure Web App, Azure Cloud Service, Azure Storage account, or any publicly accessible web server.
The origin server returns the file to an edge server in the POP.
An edge server in the POP caches the file and returns the file to the original requestor (Steve). The file remains cached on the edge server in the POP until the time-to-live (TTL) specified by its HTTP headers expires. If the origin server didn't specify a TTL, the default TTL is seven days.
Additional users can then request the same file by using the same URL that Steve used and can also be directed to the same POP.
If the TTL for the file hasn't expired, the POP edge server returns the file directly from the cache. This process results in a faster, more responsive user experience.