Part of Ilya Grigorik’s “High Performance Browser Networking” is a fascinating section on the Radio Resource Controller (RRC):

Both 3G and 4G networks have a unique feature that is not present in tethered and even WiFi networks. The Radio Resource Controller (RRC) mediates all connection management between the device in use and the radio base station. Understanding why it exists, and how it affects the performance of every device on a mobile network, is critical to building high-performance mobile applications. The RRC has direct impact on latency, throughput, and battery life of the device in use.

As someone who just has a smartphone but likes to peek under the covers, I found it compelling reading, even if I'm not directly building anything that is affected by this. If nothing else it gives me a greater appreciation of what my smartphone is doing and what sort of things in applications (and my own usage) may be using up extra battery.

(Via Can You Afford It?: Real-world Web Performance Budgets, itself via lobste.rs.)