Thursday, June 27, 2013
At Google, we're always working to make the web faster. The SPDY protocol, which is now the foundation of the upcoming HTTP 2.0 protocol, is a significant step forward. However, despite increasing bandwidth, round trip time (RTT)--which is ultimately bounded by the speed of light--is not decreasing, and will remain high on mobile networks for the foreseeable future. To continue improving network performance we need to decrease the number of round trips, something that is difficult with protocols that currently rely on the Transmission Control Protocol (TCP).
QUIC (Quick UDP Internet Connections) is an early-stage network protocol we are experimenting with that runs a stream multiplexing protocol over a new flavor of Transport Layer Security (TLS) on top of UDP instead of TCP. QUIC combines a carefully selected collection of techniques to reduce the number of round trips we need as we surf the Internet. You can learn more in the design document, but here are some of the highlights:
- High security similar to TLS
- Fast (often 0-RTT) connectivity similar to TLS Snapstart combined with TCP Fast Open
- Packet pacing to reduce packet loss
- Packet error correction to reduce retransmission latency
- UDP transport to avoid TCP head-of-line blocking
- A connection identifier to reduce reconnections for mobile clients
- A pluggable congestion control mechanism
You can learn more about QUIC in our FAQ. Our hope is that what we learn from QUIC will ultimately help us to deliver a much faster... er... QUICker Internet!
Posted by Jim Roskind, RTT Reduction Ranger, Google