When a connection is performed, a transport strategy must be put in place in order to properly move bits back and forth between the client and server. Let's recap them quickly:
WebSocket: This is an HTML5-related protocol that provides full duplex communication channels over a single TCP connection, and is available in modern web browsers and web servers
Server-Sent Events: This is a strategy based on the EventSource HTML5 support, which allows a server to stream messages to the connected clients
Long Polling: This is quite a basic technique, which involves opening a connection and keeping it artificially alive to create the illusion of a persistent connection
You might have noticed that Forever Frame, which was available with the JavaScript client library, is not there. That's because this is a purely browser-dependent strategy, and it does not apply in this case. For some more detail about transport options, please have a look at Appendix B, Insights...