Websocket, part of HTML5, is a protocol which enables
bi-directional communication between client and server. It
extends HTTP by removing the limitation on bi-directional
communication. Therefore, a websocket connection must
644start with a normal HTTP connection. Then, a handshaking
protocol is enforced to upgrade the HTTP connection to
websocket connection. Table II lists several traditional web
technologies which implement bi-directional communication
based on legacy HTTP. Compared with these technologies,
websocket provides best performance.