I learned that the cellular protocol stack wasn't as simple as it seemed when I was debugging my VoIP library under different network conditions. I would go int

I learned that the cellular protocol stack wasn't as simple as it seemed when I was debugging my VoIP library under different network conditions. I would go into the *#*#INFO#*#* menu on an Android phone and force it to a particular network type. 2G/EDGE provided just barely enough throughput for me to fit my packets through on my lowest bitrate. But sometimes there were periods when the packets would just stop coming through. This would last for a perceptible amount of time, sometimes even more than a second, but after that, all the packets I sent during that time would come through in a burst. That's how I found out about the RLC protocol that's somewhere in the stack in 2G, 3G, and 4G, and that it has this "acknowledged mode", and that in this mode it does retransmissions if there are bit errors. This also made it very clear why TCP sometimes struggles so much when running over a 2G connection. Anyway, I wish there was something like Wireshark to which I could connect a phone and see it talk to the cell towers in real time. This would really help understand how this all works.