Understanding computer networks by analogy (2000)
memo.mx
memo.mx
The BAS relation for SDN is interesting. I've always avoided any analogies with SDN since different people have different ideas on what qualifies as SDN or what SDN is going to do but that's a really good choice given the rest of the analogies.
This little project was developed I believe within a Google team, with more analogies to help you understand certain concepts, or explain them easier for your less technical comrades.
Enter at your own risk, ATM it comes up as unsecure website.
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.