What is Fastly CDN?

In this blog series, we will cover how Fastly and Sumo Logic empower organizations to deliver best-in-class user experience. For the first installment, we take a closer look at Fastly CDN--what it is and how it works.

From the amount of content produced and shared to the number of features quickly deployed in today’s agile engineering culture, the challenge to ensure high-level performance across various devices and network conditions is a familiar struggle for the modern enterprise.

End users are especially sensitive to performance issues. Content that loads too slow or interfaces that take time to respond to user actions impact user experience immensely, in ways that affect the bottom line.

Cases in point: BBC reported that they lose roughly 10% of potential users for every extra second it takes for their site to load. Amazon also reportedly loses 1% of their sales for every 100 milliseconds of delay on their site.

These are the facts: Higher latency leads to increased bounce rates. High latency leads to poor adoption. Higher latency leads to more churn.

A content delivery network (CDN) like Fastly directly addresses this challenge.

What is Fastly CDN?

Fastly is a content delivery network that makes content transmission faster.

For CDNs, the goal is always to reduce latency. Latency is the delay from the moment a user makes a request to the exact instant they receive a response. The higher the latency, the worse the user experience. CDNs reduce latency by moving the content closer to where the user is.

Imagine this: Berlin is around 5,724 miles from Los Angeles. It would take roughly 300 milliseconds for a user in LA to get a response for an image request from a server in Berlin. If the same user requests an image from a server in San Bernardino, 55 miles away, the response will be received in roughly 10 milliseconds.

The difference may seem insignificant in this example, mainly because we’re using milliseconds. But considering that typical page weight is at 3 megabytes requiring upwards of 30 request-response roundtrips, the difference in latency is definitely perceptible. Add the fact that browsers can’t make these all these requests at once, what seemed miniscule now pile up to seconds of delay, and no user likes a slow website.

Fastly’s CDN service is delivered from content caching servers in different locations.

To reduce latency, users must be able to access caches that are close to them. However, it’s nearly impossible to ensure that all possible users have caches closeby. Addressing this fact, Fastly groups caches into clusters called Points of Presence (POPs) distributed in various regions worldwide, strategically placing each one in major population centers globally.

With these POPs in place, Fastly now routes user requests to the POP closest to them to reduce the time it takes to deliver content to end-users.

Fastly currently maintains 18 PoPs in North America, eight in Europe, five in Asia, six in the Australian region, two in South America, and one in Africa.

How does Fastly Work?

Traditionally, CDNs require customers to upload content directly to distributed servers. Fastly, on the other hand, fetches and stores content from origin servers in caches on a by-request basis. This method is called reverse proxying.

By using this method, Fastly doesn’t need cache full copies of servers in POPs. In a process called provisioning, Fastly customers configure these criteria:

• What content objects will be cached
• How long content objects will be cached
• Who can access cached content
• Content encryption
• When content objects are deleted from the cache

Fastly customers specify the origin domains, servers, and applications from where the original content will be fetched. When a request is made, the closest Fastly cache to the user fetches the content from the origin server, stores it in the cache, and sends the response to the end-user.

How does Fastly Improve Site Performance?

When an end-user requests the same content object after the first time, Fastly can immediately deliver the content by retrieving the cached copy. Fastly only fetches from the origin server when the content expires based on customer configuration or if it becomes invalidated.

A process called instant purging sets Fastly apart from legacy CDNs.

With Fastly, customers would not need to worry about uploading updated content into the caches. Just by sending Fastly a short message to invalidate content, caches are instantly purged. Instant purging allows Fastly clients to fully update user-facing assets in approximately 200 milliseconds, a tremendous improvement from the legacy CDN upload process that could take up to an hour.

Instant purging also makes it possible for Fastly customers to serve dynamic content, something that legacy CDNs can’t deliver. With Fastly, any HTTP request can be cached. This allows Fastly to simply fetch the dynamic page from the origin server and the customer only has to send a purge request whenever the base data-model changes. There are certain situations where Fastly customers can leverage this by simply adding a hook in the model-level of an application.

Why do I need Fastly CDN?

As the internet continues to change, users demand better experiences. Fastly ensures better user experiences and high-level performance on any platform by moving data and applications to the network edge, closer to users.

Because of the apparent advantage Fastly provides, they call some of the biggest names across various verticals their customers. Here are some Fastly customer wins:

• Digital publisher BuzzFeed users halved their page load times
• The New York Times was able to provide smooth real-time updates to 2 million viewers on election night
• Video platform Vimeo reduced response times worldwide, reducing latency by 50% in APAC
• Stripe reduced the time to load their checkout form by 80%

It’s not only user experience that Fastly significantly improves. The business benefits of using Fastly’s CDN can’t be understated.

• Business cost reduction through bandwidth and storage cost savings
• Accelerated workflows through better control and flexibility
• Enhanced security and user trust by ensuring secure HTTPS sites for all customer properties

How Sumo Logic & Fastly Integrate Well

At Sumo Logic, we are committed to helping enterprises make sense of their metrics and use it to secure their systems and improve performance.

With the massive amounts of traffic coursing through Fastly’s caches on behalf of their customers, it’s critical to analyze logs and get real-time data on the performance and security of all their properties. This is why we developed the Sumo Logic App for Fastly.

The Sumo Logic App for Fastly enables Fastly users to streamline the analysis of logs, and correlate end-user and performance data with origin server data. Analysts use the Sumo Logic App for Fastly’s pre-built dashboards to monitor applications and spot patterns instead of tediously digging through log files, making it simpler to ensure and improve security.

In the next post of the Fastly and Sumo Logic blog series, we will further address why it’s crucial to analyze Fastly logs and we’ll go deeper into how to monitor Fastly performance with Sumo Logic.