QUIC: Quick UDP Internet Connections


I was researching HTTP/2 yesterday (which I ended up blogging here. While analysing the traffic to capture HTTP/2 packets, I noticed a bunch of packets with a protocol named QUIC. I had not heard about it before so looked it up. Apparently it’s an experimental protocol developed by Google.

The documentation describes it as “TCP+TLS+HTTP2 but implemented on top of UDP”.

One neat feature it supports is “multiplexing”. In TCP when a packet is lost it needs to be retransmitted, otherwise no streams on the connection can continue. But with QUIC “healthy” streams can continue without delay caused by the streams with lost packets.

Looks like currently it’s only supported by Google Servers and Chrome on the client.

There is a Chrome extension called HTTP/2 and SPDY indicator which also shows QUIC sessions.