Ilya Grigorik wrote:Our goal is to cover what every developer should know about the network: what protocols are being used and their inherent limitations, how to best optimize your applications for the underlying network, and what networking capabilities the browser offers and when to use them.

In the process, we will look at the internals of TCP, UDP, and TLS protocols, and how to optimize our applications and infrastructure for each one. Then we'll take a deep dive into how the wireless and mobile networks work under the hood--this radio thing, it's very different--and discuss its implications for how we design and architect our applications. Finally, we will dissect how the HTTP protocol works under the hood and investigate the many new and exciting networking capabilities in the browser:

• Upcoming HTTP 2.0 improvements
  
• New XHR features and capabilities
  
• Data streaming with Server-Sent Events
  
• Bidirectional communication with WebSocket
  
• Peer-to-peer video and audio communication with WebRTC
  
• Peer-to-peer data exchange with DataChannel
  

Understanding how the individual bits are delivered, and the properties of each transport and protocol in use are essential knowledge for delivering high-performance applications. After all, if our applications are blocked waiting on the network, then no amount of rendering, JavaScript, or any other form of optimization will help! Our goal is to eliminate this wait time by getting the best possible performance from the network.