In-Depth Investigation of CDN: Part 2
Learn about content consistency mechanisms and the deployment of the proxy server in a CDN.
In this lesson, we learn how content consistency can be achieved using different consistency mechanisms. We also learn about where we should deploy the proxy servers and the difference between CDN as a service and specialized CDN.
Content consistency in CDN
Data in the proxy servers should be consistent with data in the origin servers. There’s always a risk of users accessing stale data if the proxy servers don’t remain consistent with the origin servers. Different consistency mechanisms can be used to ensure consistency of data, depending on the push or pull model.
Periodic polling
Using the pull model, proxy servers request the origin server periodically for updated data and change the content in the cache accordingly. When content changes infrequently, the polling approach consumes unnecessary bandwidth. Periodic polling uses time-to-refresh (TTR) to adjust the time period for requesting updated data from the origin servers.
Time-to-live (TTL)
Because of the TTR, ...