WebSockets is finally going prime time. The Internet Engineering Task Force gave a nod, yesterday, to RFC 6455, which describes how WebSockets work. Essentially, this document defines a way for browsers and Web servers to communicate with one another over port 80 in a full duplex fashion. That means TCP packets go both ways through the same port, thanks to a bit more protocol overhead on the part of the browsers and servers.
The IETF has upgraded RFC 6455 to a Proposed Standard, which is the last step before it becomes a fully supported Internet Standard.
This will simplify life for developers, if it hasn't already. The standard, even before it reached standards level, was already supported in Firefox 4 and beyond. Unfortunately, due to some security limitations of the previous versions of the protocol, WebSockets was disabled by default in most browsers until only very recently.
There's still time for changes to be made to this standard, but it's good to see that the work towards HTML5's completion is moving along at an acceptable pace outside of the W3C as well.
From the release email:
The WebSocket Protocol enables two-way communication between a client
running untrusted code in a controlled environment to a remote host
that has opted-in to communications from that code. The security
model used for this is the origin-based security model commonly used
by web browsers. The protocol consists of an opening handshake
followed by basic message framing, layered over TCP. The goal of
this technology is to provide a mechanism for browser-based
applications that need two-way communication with servers that does
not rely on opening multiple HTTP connections (e.g., using
XMLHttpRequest or iframes and long polling). [STANDARDS-TRACK]
This document is a product of the BiDirectional or Server-Initiated HTTP Working Group of the IETF.
This is now a Proposed Standard Protocol.