Google built QUIC as they got tired of waiting for the internet to catch up :) Let me explain what it is, why it is needed, and how you can see it in action.
Imagine you are watching a live video, and a frame gets lost. Instead of skipping it and moving on, the player waits for retransmission and shows a frustrating spinner. Now, in live video, losing a frame or two is fine, but a pause is much worse UX.
This is where QUIC comes into the picture and solves the problem.
QUIC is a transport protocol that runs on top of UDP, and you can think of it as TCP’s faster cousin - sorry :) It was designed from scratch to eliminate bottlenecks that make web browsing feel sluggish, especially on mobile networks. QUIC allows you to
- have multiple streams in one connection
- resume connections instantly, and it takes literally 0-RTT
- seamlessly switch between WiFi and cellular without dropping the connection
Here’s a real scenario - say, you are on a video call while walking from WiFi to cellular.
With TCP/HTTP/2:
- WiFi signal weakens - connection drops
- Phone switches to cellular - new IP address
- Video app must re-establish the entire connection
- Handshake + TLS
- 3-5 seconds of “connecting…” screen
- Call resumes
But, with QUIC,
- WiFi signal weakens - QUIC detects degradation
- Phone switches to cellular - QUIC migrates connection to new IP
- connection migration to the switch seamlessly
- maybe 200ms hiccup, if anything
- call continues without interruption
If you see pages loading instantly, or video not buffering, or an app that stays connected as you move around, very likely it is QUIC-based (but do check once).
To see this in practice, you can actually run a QUIC server locally in your preferred programming language and benchmark. Like always, let LLMs to do the grunt work.
Hope it helps.