There isn’t a lot of lollygagging permitted in today’s world. When we want something, we want it as fast as possible, whether it’s our Amazon Prime orders or our web content. This means industries have to be constantly striving for faster, better delivery, and luckily for everyone involved, all that striving is paying off for many industries. This very much includes internet technology, especially when it comes to cache servers.
The Not-Fast and the Furious
For many internet users, the most important factor in a website’s performance is speed — how fast are pages loading? According to kissmetrics, nearly half of internet users expect a website to load in two seconds or less and are likely to abandon a website altogether if it doesn’t load within three.
This need for speed is recognized by Google and other major search engines, which have made page load time an important factor in search engine rankings. So not only do website owners need to improve page load time to keep users happy, but to keep drawing users in by being visible in search results. Good thing there’s a tool for that.
A CDN Overview
CDN stands for content delivery network, which is essentially a global network of proxy cache servers that exist to deliver website content to users as efficiently as possible. When a user goes to a website that uses a CDN, he or she is automatically redirected to the proxy cache server with the closest geolocation. This cuts down on the physical distance browser requests and website content have to travel, which cuts down on how long it takes that content to load on a web page.
In addition to improved page load time, CDNs offer website owners a number of benefits, including load balancing, built-in DDoS protection, additional DDoS protection in some cases, network optimization and reduced bandwidth bills.
A CDN has many significant components, but there is none more significant than its proxy cache servers. As CDN provider Incapsula explains, cache servers are essentially repositories for website content, giving local users fast access to cached content. Instead of a request for a web page traveling from a user’s browser all the way to a website’s origin server, it goes to the closest cache server, which zips back all of the requested content it has stored.
Think of it like the warehouse system of a massive online retailer. Instead of having one warehouse full of all the items the online retailer sells, requiring every purchased item to be sent from one place no matter how far it has to travel to reach the buyer, it has a network of warehouses around the world. Orders are automatically sent to the warehouse closest to the buyer where commonly purchased items are ready to be sent out, eliminating much of the distance orders would have to travel if they all came from a single central warehouse.
Static and Dynamic
There are two broad types of website content. Static content is content that largely remains the same; it’s not expected to change. Dynamic content, on the other hand, is expected to change depending on factors such as which user is visiting the website, at what time the website is being visited, or from where in the world. Dynamic content has to be generated on the fly.
All CDNs cache static content, and leading CDNs will also intelligently cache dynamic content for the period in which it does not change. What a cache server does and does not store as well as how cached content is stored also depends on rules set for individual content files. Some content files will be labeled no-cache or no-store, some content files will have rules for being compressed or uncompressed, and most content files will have rules for long it can be cached before it has to be re-fetched from the origin server to ensure content freshness.
It used to be that these classifications for content files had to be determined by a web developer using cache headers that transmitted caching information to the servers. However, this is an inefficient and suboptimal method. Modern, superior CDNs use a learning-based approach to apply optimized caching rules and efficiently cache a wider range of content.
Giving the People What They Want
As much as website speed demands can be frustrating for site owners, and as tempting as it may be to write off the idea that users need a site to load in under three seconds and a consumer needs a giant bag of Lucky Charms marshmallows to arrive in two days with free shipping, this is the world we’re living in. You get fast or you get left behind. Or in internet technology terms, you get a CDN or you get left behind.