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Store-and-forward is actually a pretty simple improvement based on circuit-based routing -- we can understand it as circuit-based routing, where the "circuit" now has much better granularity. Continue with the highway analogy, instead of reserving the entire path from Pittsburgh to San Francisco, we have 100 checkpoints along the way, and reserve them one after another.


Is there a difference between a router and a switch?


@IntergalacticPeanutMaker The course didn't try to distinguish them


If different packets from the same message can travel in different paths, and therefore arrive at different times, how do you keep track of the order of packets when assembling the message? A naive way is store the total number of packets and an index.


Araina and CaptainBlueBear provide pretty good explanations and graphics for how the entire message is reassembled from out-of-order packets here. Basically the header contains the information that you talked about (the index and number of packets).


What advantages does store & forward have over cut-through?


@cmusam I wouldn't call it advantage, but store & forward is simpler, and it has less contention while a single package is being transferred. However, like circuit-based vs. packet-based switching, we really want cut-through in modern usage since parallel processing is important.