> To me the thing that is difficult to wrap my head around is how congestion control, back pressure, and buffering at various levels work. Snarky answer: that'

> To me the thing that is difficult to wrap my head around is how congestion control, back pressure, and buffering at various levels work. Snarky answer: that's because they don't. Attempts at humor aside: It really helps to understand a bit about queuing theory to wrap your head around these things. Each packet being an independent event has some unintuitive consequences. Each switch or router or etc (middlebox) in the path from one endpoint to the other adds the packet to a queue (which is what the buffers are), and that queue may be filled by other flows coming into the middlebox from different ports.