New – HTTP/3 Support for Amazon CloudFront

Amazon CloudFront is a content delivery network (CDN) service, a network of interconnected servers that is geographically closer to the users and reaches their computers much faster. Amazon CloudFront reduces latency by delivering data through 410+ globally dispersed Points of Presence (PoPs) with automated network mapping and intelligent routing.

With Amazon CloudFront, content, API requests and responses or applications can be delivered over Hypertext Transfer Protocol (HTTP) version 1.1, and 2.0 over the latest version of Transport Layer Security (TLS) to encrypt and secure communication between the user client and CloudFront.

Today we are adding HTTP version 3.0 (HTTP/3) support for Amazon CloudFront. HTTP/3 uses QUIC, a user datagram protocol-based, stream-multiplexed, and secure transport protocol that combines and improves upon the capabilities of existing transmission control protocol (TCP), TLS, and HTTP/2. Now, you can enable HTTP/3 for end user connections in all new and existing CloudFront distributions on all edge locations worldwide, and there is no additional charge for using this feature.

What is HTTP/3?
HTTP/3 uses QUIC and overcomes many of TCP’s limitations and brings those benefits to HTTP. When using existing HTTP/2 over TCP and TLS, TCP needs a handshake to establish a session between a client and server, and TLS also needs its own handshake to ensure that the session is secured. Each handshake has to make the full round trip between client and server, which can take a long time when client and server are far apart, network-wise. But, QUIC only needs a single handshake to establish a secure session.

Also, TCP is understood and manipulated by a myriad of different middleboxes, such as firewalls and network address translation (NAT) devices. QUIC uses UDP as its basis to allow packet flows in an enterprise or public network and is fully encrypted, including the metadata, which makes middleboxes unable to inspect or manipulate its details.

HTTP/3 streams are multiplexed independently to eliminate head-of-line blocking between requests and responses. This is possible because stream multiplexing occurs in the transport layer as opposed to the application layer like HTTP/2 over TCP. This enables web applications to perform faster, especially over slow networks and latency-sensitive connections.

Benefits of HTTP/3 on CloudFront
Our customers always want to provide a faster, more responsive and secure experience on the web for end users. HTTP/3 provides benefits to all CloudFront customers in the form of faster connection times, stream multiplexing, client-side connection migration, and fewer round trips in the handshake process to reduce error rates.

QUIC connections over UDP support connection reuse with a connection ID independent from IP address/port tuples so users have no interruption or impact. Customers operating in countries with low network connectivity will see improved performance from their applications.

CloudFront’s HTTP/3 support provides enhanced security built on top of s2n-quic, an open-source Rust implementation of the QUIC protocol added to our set of AWS encryption open-source libraries, both with a strong emphasis on efficiency and performance.

If you enable HTTP/3 in CloudFront distributions, the users can make HTTP/3 viewer request to CloudFront edge locations. Past the edge location, we have highly reliable networks within AWS Cloud and CloudFront will continue to use HTTP/1.1 for origin fetches. So, you don’t need to make any server-side changes in order to make your content accessible via HTTP/3.

For some types of applications, like those requiring an HTTP client library to make HTTP requests, customers may need to update their HTTP client library to a version that supports HTTP/3. But if for some operational reason clients cannot establish a QUIC connection, they can fall back to another supported protocol such as HTTP/1.1 or HTTP/2.

How to Enable HTTP/3
To enable HTTP/3 connection, you can edit the distribution configuration through the CloudFront console. You can select HTTP/3 in Supported HTTP versions on an existing distribution or create a new distribution without any changes to origin. You can use the UpdateDistribution API or use the CloudFormation template.

After deploying your distribution, you can connect with a browser that supports HTTP/3, such as the latest version of Google Chrome, Mozilla Firefox, and Microsoft Edge, and Apple Safari after turning it on manually. To learn more about web browser support, see the Can I Use – HTTP/3 Support page.

From web developer tools in your browser, you can see the HTTP/3 requests made when a page is loaded from the CloudFront. The image below is an example of Mozilla Firefox.

You can also add HTTP/3 support to Curl and test from the command line:

$ curl --http3 -i https://d1e0fmnut9xxxxx.cloudfront.net/speed.html
HTTP/3 200
content-type: text/html
content-length: 9286
date: Fri, 05 Aug 2022 15:49:52 GMT
last-modified: Thu, 28 Jul 2022 00:50:38 GMT
etag: "d928997023f6479537940324aeddabb3"
x-amz-version-id: mdUmFuUfVaSHPseoVPRoOKGuUkzWeUhK
accept-ranges: bytes
server: AmazonS3
vary: Origin
x-cache: Miss from cloudfront
via: 1.1 6e4f43c5af08f740d02d21f990dfbe80.cloudfront.net (CloudFront)
x-amz-cf-pop: ICN54-C2
alt-svc: h3=":443"; ma=86400
x-amz-cf-id: 6fy8rrUrtqDMrgoc7iJ73kzzXzHz7LQDg73R0lez7_nEXa3h9uAlCQ==

Customer Stories
Several AWS customers including Snap, Zillow, AC3/Movember, Audible, Skyscanner have already enabled HTTP/3 on their CloudFront distributions. Here are some of their voices:

Snap Inc is a social media company that offers Snapchat, an app that offers a fast and fun way to connect with close friends to its community around the world. On AWS, Snap now supports more than 306 million Snapchat users sending over 5.4 billion Snaps daily with 20 percent less latency than its prior architecture.

Mahmoud Ragab, Software Engineering Manager at Snapchat said:

“Snapchat helps millions of people around the world to share moments with friends. At Snapchat, we strive to be the fastest way to communicate. This is why we have been partnering with Amazon Cloudfront for fast, high-performance, low latency content delivery, leveraging QUIC on Cloudfront.

It offers significant advantages while sending and receiving content, especially in networks with lossy signals and intermittent connectivity. Improvements offered by QUIC, like zero round-trip time (0-RTT) connection setup and improved congestion control enables an average of 10% reduction in time to first byte (TTFB) while lowering overall error rates. Lower network latencies and errors make Snapchat better for people all over the world.

With early access to QUIC, we’ve been able to experiment and quickly iterate and improve server-side implementation and optimize integration between the client and the server. Both companies will continue to collaborate together as QUIC is made more widely available.”

Zillow is a real estate tech company that offer its customers an on-demand experience for selling, buying, renting and financing with transparency and nearly seamless end-to-end service. Since 2015, Zillow has increased the availability of its imaging system by using Amazon S3 and Amazon CloudFront.

Craig Link, Chief Cloud Architect at Zillow said:

“We are excited about the launch of HTTP/3 support for Amazon CloudFront. Enabling HTTP/3 on CloudFront was a seamless transition and our synthetic test and ad-hoc usage continued working without issue.”

AC3 is an Australia-based AWS Managed Services partner and has supported our customer, Movember Foundation, one of the leading charities for men’s health. Running an international charity that handles donations, data, events, and localized websites in 21 countries can pose some technical challenges. Born in the cloud, Movember has leveraged AWS technology in adopting new working models, ensuring a flexible IT platform, and innovating faster.

Greg Cockburn, Head of Hyperscale Cloud at AC3 said:

“AC3 is excited to work with their longtime partner Movember enabling HTTP3 on their CloudFront distributions serving web and API frontends and is encouraged by the performance improvements seen in the initial results.”

Now Available
The HTTP/3 support for Amazon CloudFront is now available in all 410+ CloudFront edge locations worldwide with no additional charge for using this feature. To learn more, see the FAQ and Developer Guide of Amazon CloudFront. Please send feedback to AWS re:Post for Amazon CloudFront or through your usual AWS support contacts.

– Channy