Everything about LiteSpeed QUIC ( Quick UDP Internet connections )

Posted on December 26th, 2018

Everything about LiteSpeed QUIC ( Quick UDP Internet connections )


QUIC stands for Quick UDP Internet connections. This is an experimental transport layer network protocol which is designed to provide security protection equivalent to TLS/SSL. QUIC helps to reduce connection establishment time and improve congestion control.


Connection establishment

The two protocols HTTP/2 and SPDY provide a progress in improving application performance, but they fail to resolve the problem of high round trip time (RTT) which is also called as a round-trip delay, is the time required for a pulse signal or packet to travel from a specific source to a destination and back again. The end-user can determine RTT to and from an IP by pinging that IP address. QUIC is used to solve the problem of high RTT by reducing the number of trips that must be taken. Multiple round trips are required while establishing a secure network connection with https. The QUIC protocol combines some of these round trips, thereby it reduces the number of trips. QUIC uses UDP (User Datagram Protocol) instead of ubiquitous TCP.


Congestion Control

QUIC deals with packet loss more efficiently than other protocols. TCP and HTTP/2 rely on consecutive packets which mean the connection will close when one packet goes away. On the other hand, QUIC and UDP protocols don’t require to arrive the packets in order.

LiteSpeed provides the first production grade mass market for implementing QUIC for the public. LiteSpeed is the solution to serve your web content using QUIC protocol. The website loads with high speed with the use of QUIC. QUIC loads page quicker than HTTP/2. QUIC uses UDP protocol over ports 80 and 443. This permits clients to bypass transparent proxies and also suggest that forwarding proxies can also be bypassed.


Benefits of QUIC

1) Reliability: QUIC is reliable transport for TLS+HTTP based on UDP. This avoids the slow start and provides reliability when switching networks. The website load faster and more reliable with QUIC.

2) Reduces connection establishment time: QUIC helps to reduce the number of round trips (RTT) required for setting up a secure connection. QUIC connections are 0-RTT, which means that on most QUIC connections, data can be sent immediately without waiting for a reply from the server, as compared to the round trips required for TCP+TLS before application data can be sent.

3) Improved congestion control: QUIC consists of a pluggable congestion control and richer signalling than TCP, which enables QUIC to provide richer information to congestion control algorithms than TCP.

4) Multiplexing without the head of line blocking.

5) Forward error correction: The protocol provides error correction by recovering the lost packets without waiting for a retransmission. It uses an XOR-based FEC scheme.

6) Privacy assurances comparable to TLS (e.g. HTTPS)

7) Reduced bandwidth and increased channel status responsiveness.

8) Connection Migration: QUIC connections are identified using a 64-bit connection ID whereas TCP connections are identified by a 4 tuple of source address, destination address and its ports which mean that if a client’s IP address changes any active TCP connections are no longer valid. If the client’s IP address changes in QUIC connection, it can continue to use the old connection ID from the new IP address without any requests.


How to verify QUIC is enabled

Chrome has an extension which allows seeing the QUIC protocol works on your website. Install the following extension.


You will see a lightning bolt in the Chrome toolbar. Blue indicates HTTP/2 is enabled where green indicates HTTP/2 + QUIC.



Leave a Reply