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QUIC: the communication protocol of the future or the road to nowhere.

Can an experimental standard displace the fundamental TCP and UDP?

QUIC: the communication protocol

Although much of our lives are now online, we rarely give much thought to how things actually work. In the background, when we open a website on our smartphone, there are a lot of activities going on that we don't notice and often have no control over.

Network packets are constantly being sent to the router and then back to the device even when we don't seem to be doing any active network activity. Even when we are just browsing a small web page, our devices are exchanging a significant amount of data with the cell tower and other equipment.

In this article, we'll talk about the QUIC network transfer protocol and how it may soon change the way we interact with web applications.

A brief history of the QUIC protocol and its relationship to Google

In the early 2010s, Google engineers were actively looking for a way to speed up and improve web applications. Not everyone had a stable high-speed internet connection, which definitely made it difficult to navigate the global web. A potential solution was soon found, and it was designed to greatly optimize user interaction with web services.

So, in 2012, Jim Roskind, an American software engineer working at Google at the time, led a new internal project for the company called Quick UDP Internet Connections (QUIC). The idea was to maximize the speed of the current User Datagram Protocol (UDP) by adding security and congestion management features.

Network congestion usually refers to the degradation in quality of service that occurs when a network node or link carries more data than it can handle. Typical consequences include queuing delays, packet loss, or blocking of new connections. A consequence of congestion is that a gradual increase in offered load results in a decrease in network throughput.

Long-term testing of QUIC has shown promising results, but for a number of reasons the technology remained experimental for many years and has yet to be widely adopted. In the early 2020s, Google has transferred the project to the Internet Engineering Task Force (IETF) to finalize the standard.

Currently, the QUIC protocol is supported to some extent in various web browsers and operating systems, but in the future, experts expect its active and rapid growth.

What are the advantages and disadvantages of QUIC?

The QUIC protocol is a significant step forward for the entire networking industry, but there are a number of factors that are potentially holding it back. Below we look at the key advantages and potential disadvantages of the QUIC protocol.


  • Less latency. Faster response times will benefit real-time applications such as video conferencing or online gaming.

  • Increased efficiency under network congestion. Efficient handling and routing of network traffic, even under heavy loads, keeps everything running smoothly.

  • Enhanced security. Because security features are implemented directly in the protocol, QUIC can significantly increase the security of network packets.

  • More than one data stream at a time. Implementing support for multiple data streams on a single connection allows applications to be more multitasking and efficient.

  • Seamless reconnection when you change networks. When you switch from Wi-Fi to 5G, your connection will reconnect even faster than with TCP/UDP. Disadvantages

  • Full implementation takes time. Since any new technology or protocol takes time to be thoroughly implemented, it may be many years before QUIC becomes a uniform international standard.

  • Potential security issues. Because QUIC is built on UDP, it can be difficult for firewalls to inspect network traffic for threats. To meet these new requirements, developers will need to incorporate new QUIC-based network packet tracking techniques into their firewalls.

  • Increased development costs. QUIC is a relatively new protocol and may be more complex than previous protocols, which likely increases the development costs associated with it.

  • Potential interoperability issues. TCP is the most widely used protocol for many modern and older devices, so QUIC operation is not guaranteed to work absolutely everywhere.

  • Fewer testing options for network managers. Because of the way QUIC encryption works, network managers may need more time to scan and detect threats in real time. They should utilize firewalls with QUIC detection and other methods to keep up with potential security threats.

QUIC: the communication protocol

What is TCP and how is it used?

If you have tried to configure a static IP address on one of your devices or change DNS servers, you have probably seen the presence of options to configure TCP/IPv4 or TCP/IPv6.

The Transmission Control Protocol (TCP) converts requested network data into packets to be sent and checks them for errors. In turn, the Internet Protocol (IP) addresses and correctly routes these packets to all connected devices on the network.

TCP/IP enables devices to connect to the Internet by assigning them unique IP addresses and allowing the LAN router to identify them. The router can then send data packets to and from the appropriate devices, creating a constant stream of network traffic.

All of this, combined with various other protocols and MAC addresses, allows devices to both connect to the Internet and communicate locally with each other.

How does TCP relate to QUIC?

TCP/IP is still the most common method of connecting devices to the Internet. In general, QUIC, like TCP, is a transport protocol. However, it approaches the data transfer process very differently.

First, QUIC is built on the UDP protocol rather than TCP. UDP prioritizes speed over reliability. This approach does not always guarantee that data packets will arrive in the right sequence or arrive at all.

In general, when using UDP, you can expect some packet loss and decreased efficiency in exchange for increased speed. QUIC, on the other hand, builds on the same foundation and provides a mechanism to avoid packet loss whenever possible.

TCP has a higher level of efficiency in delivering packets, but at lower speeds than UDP. TCP can resend lost packets as a fallback, but this is less efficient than sending everything on the first try.

Compared to TCP, QUIC sends packets at a higher rate and with better reordering of lost packets. QUIC also encrypts packets immediately, whereas TCP uses a separate protocol for encryption.

QUIC provides the speed of UDP with the efficiency-enhancing features of TCP. In other words, it uses only the best of both protocols.

Will QUIC ever replace TCP and UDP?

Since TCP has been the most widely used protocol for data transfer over the network for many years, it will definitely remain the default standard for some time to come. However, QUIC is gaining momentum and adoption continues to increase year after year.

Most likely, QUIC will not replace TCP or UDP completely, because each protocol, after all, has a specific purpose and must continue to coexist in the future.

However, QUIC may well improve local area networks for desktop devices and improve the efficiency of 5G mobile networks. This would be handy for streaming content at home or web surfing on the road.

What does HTTP/3 mean for the future of QUIC?

While HTTP/3 is the latest and most advanced standard for information transfer on the World Wide Web, HTTP/2 and HTTP/1 still power much of the Internet.

HTTP/3 supports QUIC features by default, while HTTP/2 and HTTP/1 rely specifically on TCP. This means that the adoption rates of HTTP/3 and QUIC are directly related to each other, so the growth in popularity and ubiquity of both should occur at about the same time.

Which operating systems already support QUIC by default?

In addition to the need for the industry to implement support for HTTP/3 and QUIC, similar integration is needed in operating systems.

Proper native support for QUIC allows devices to utilize the protocol's features at the system level. The good news is that the latest versions of Windows and macOS already support QUIC by default.

For example, if you have at least Windows 10 21H1 or any version of Windows 11 installed, your device definitely supports the QUIC protocol. For macOS, if you have Big Sur (macOS version 11) or higher installed, your device also has the necessary support.

Linux support is still under development, but some distributions may already offer external drivers capable of providing access to QUIC functionality.

It is likely that we will not see proper native support for QUIC in Linux until the protocol is well established in the industry.

Does Android support the QUIC protocol?

There is some initial support for the QUIC protocol on mobile devices. For Android, developers use Cronet to implement HTTP/3 functions in their applications. This approach also allows them to use QUIC functions in their applications separately.

Android does not support the QUIC protocol at the system level, but app developers can use it when needed. For example, the Google Chrome web browser supports QUIC because it has support for HTTP/3. QUIC server-side websites also work in all modern versions of Google Chrome.

Starting with Android 11, DNS-over-HTTP/3 (DoH3) is fully supported with the Private DNS feature. However, it only allows you to choose from pre-configured DNS server providers such as Google DNS or Cloudflare DNS. Starting with Android 13, this feature allows you to specify a hostname for DoH3 instead of relying on a list of pre-configured providers.

Not all servers support this feature, but the list keeps growing. For example, private DNS with DoH3 allows for faster DNS lookups on Android using HTTP/3, which by default provides certain QUIC features.

Does iOS support the QUIC protocol?

Apple supports the QUIC protocol and HTTP/3 starting with iOS 15. If a device is using iOS 15 or later and the app server supports QUIC features, that device will definitely work with the QUIC protocol.

Apple's Safari web browser appears to support HTTP/3, but it may need to be manually enabled. Some versions of the system may have it enabled by default, which is a good sign for the future of QUIC. Thus, the Safari web browser should support the QUIC protocol as long as HTTP/3 is enabled in the application's settings.


Technological progress is inevitable, and new protocols will gradually supplant outdated solutions. Although TCP will probably remain the gold standard of the network for many years to come, the QUIC protocol will sooner or later displace it from its leading position. And it is not surprising, because it combines the best of TCP and UDP, offering unique features.

Transitioning to new standards is always challenging and time-consuming, but in the end, it will open the way to more efficient, secure and productive communications. The willingness to adapt to change and adopt cutting-edge technologies is key to success in a rapidly evolving digital world.

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