This blog is the final installment in a 5-part series on APMdigest where I discuss web application performance and how new protocols like SPDY, HTTP/2, and QUIC will hopefully improve it so we can have happy website users.
It has been almost a year since HTTP/2 has been a ratified standard. I talked about how widely support it is - only 4% of the top 2 million Alexa sites truly support it.
Does your website support it? What about your web host provider?
One place to check is the Google Chrome browser itself by going to Chrome Web Tools.
By now, most web browsers support the new version of HTTP. The top five, Chrome, Firefox, IE/Edge, Opera and Safari all support HTTP/2, at least partially. The top two widely used web servers, Apache and Nginx, support it as well.
Previously, I mentioned a number of workarounds that developers used to make their websites faster with HTTP/1.1. Now with HTTP/2, some of these workarounds can actually degrade performance with HTTP/2 implementation.
With only one connection per host that is allowed with HTTP/2, domain sharding can hurt a developer's attempt to improve performance. So if there was used previously, an upgrade to HTTP/2 means that the domains must be unsharded.
However, care must be taken with this. Doing this must be tested on a case-by-case basis. Some large files are able to compress better than smaller files. So it may not be to your advantage to uncombine the files if you have a lot of smaller files.
Inlining scripts directly into the HTML was another way to reduce the number of connections and round-trips to the server. With HTTP/2, this is no longer needed with only one TCP connection.
HTTP/2 Pros & Cons
There are number of advantages of using HTTP/2, including:
■ Substantially and measurably improve end-user perceived latency over HTTP/1.1 using TCP
■ Address the head of line blocking problem in HTTP
■ Not require multiple connections to a server to enable parallelism, thus improving its use of TCP
■ Retain the semantics of HTTP/1.1, like header fields, status codes, etc.
■ Clearly define how HTTP/2.0 interacts with HTTP/1.x via new Upgrade header field
But, despite these advantages, there are still some disadvantages that the new protocol version has not addressed.
Some disadvantages are:
■ Unable to get around TCP head of line blocking, particularly during packet loss
■ TCP's congestion avoidance algorithm increases serialization delay
■ TLS connection setup still takes time
■ Binary format (for people like me) makes troubleshooting a bit more difficult, not being able to see plaintext, without TLS encryption keys
We Need to Be QUIC
So we see that we still have a number of limitations even with HTTP/2. Although, I have to admit, the last one is somewhat selfish.
One big limitation is the TCP protocol. Due to its connection-oriented nature, there's no getting around the head of line blocking and the time it takes to open and close the connection.
Google wanted a way around this, and in 2012 set out to develop a protocol that runs on top of UDP, which is connectionless protocol. The protocol is called Quick UDP Internet Connections, or QUIC. Another clever name by Google?
Clever or not, Google needed a protocol with quicker connection setup time and quicker retransmissions. Unlike TCP, UDP would allow for this. They wanted to take some of the benefits of the work done with SPDY, that ultimately went into the HTTP/2 standard, such as multiplexed HTTP communication, but running over UDP rather than TCP.
The main goal? To reduce overall latency across the Internet for a user's interactions.
QUIC implements various TCP features, but without the limitations, such as the round-trip time for connection setup, flow control, and congestion avoidance. With UDP's connectionless orientation, RTT is zero since UDP just starts sending data when it needs to rather than talking to the other side to ensure it's available to talk.
Where is QUIC?
The most common place I've come across QUIC being used is on YouTube.
Have you ever compared the speed of a YouTube video compared to some of the other providers like Wistia and Vimeo? Where I live, I'll be lucky to get 3Mbps from my ISP. Watching a video on YouTube rarely buffers. I can almost always count on buffering when watching a video hosted on Wistia or Vimeo. As you can see in the screenshot below, the protocol being used on YouTube is a mix of QUIC and SPDY.
Contrast that to the screenshot I took from Wistia's site, below.
They are still largely using HTTP/1.1. They're not even on HTTP/2 yet. I'm sure they are doing a number of other things to make their web properties faster, but that explains to me why I rarely get any buffering on YouTube compared to Wistia.
If the speed with which SPDY was tested and went into the HTTP/2 standard, which took about three years from SPDY draft release to HTTP/2 draft release, is it possible that we could have a replacement for the TCP protocol on the web in the next couple of years? This should be interesting and exciting!
Jean Tunis is Senior Consultant and Founder of RootPerformance.
Hybrid and remote work environments have been growing significantly in the past few years. As individuals move away from traditional office settings in today's new remote and hybrid environments, many operational issues such as poor visibility into asset status and refreshes, unaccounted assets, and overspending on software are becoming a bigger challenge for IT departments ...
MLOps or Machine Learning Operations are a combination of best processes and practices that businesses use to run AI successfully ... While it is a relatively new field, MLOps is a collective effort that captured the interest of data scientists, DevOps engineers, AI enthusiasts, and IT ...
The data is in: enterprises are not happy with their managed service providers (MSPs) and cloud service providers (CSPs). According to the latest CloudBolt Industry Insights report, Filling the Gap: Service Providers' Increasingly Important Role in Multi-Cloud Success, 80% are so unsatisfied with their existing MSP and/or CSP, they are actively looking to replace them within 12 months ...
The last two years have accelerated massive changes in how we work, do business, and engage with customers. According to Pega research, nearly three out of four employees (71%) feel their job complexity continues to rise as customer demands increase, and employees at all levels feel overloaded with information, systems, and processes that make it difficult to adapt to these new challenges and meet their customers' growing needs ...
Investing in employees will always be smart business. And right now, investing in employees means giving people the resources — and ability — to optimize performance ... For pretty much every company, that means delivering the digital tools necessary to facilitate seamless, secure, user-friendly access and connectivity ...
Digital transformation can be the difference between becoming the next Netflix and becoming the next Blockbuster Video. With corporate survival on the line, "digital transformation" is no longer merely an impressive buzzword to throw around in boardrooms. It's the ticket for entry into the digital era, a fundamental business strategy for every modern company ...
IT infrastructure has rapidly evolved over the last decade, and as a result important specialized tools have been developed and an entire dedicated industry has grown up to serve the need for monitoring these IT systems and services in order to keep them operational and efficient ...
At Cisco AppDynamics, we recently conducted research exploring consumer attitudes and behaviors in relation to wearable technology ... In our study, 87% of global consumers claimed that trust is a critical factor when choosing a wearable medical device or application brand. And, 86% expect companies offering wearable technology and applications to demonstrate a higher standard of protection for their personal data than any other technology they use ...
You've been here before: waiting for a web page to load. You keep refreshing it, but still no luck. How many times will you try to reload the page before visiting a different site? Probably not too many. Brands today have just a few moments at most to captivate and delight potential customers ...
In the DevOps world, observability is trumpeted and lauded in many corners. However, in reading much of the coverage, there seemed to be some more fundamental issues at play. It's time to demystify the idea of observability, shedding light on what it means in a broader context. And once we break down the concept and its true value to an organization, let's answer a more important question: Are we approaching an observability tipping point? ...