Most of us studied circuit and packet switching as course material. Here is what it actually looks like inside a router. The textbook defines store-and-forward in one sentence: a packet switch "must receive the entire packet before it can begin to transmit the first bit of the packet onto the outbound link" (Kurose & Ross, Computer Networking: A Top-Down Approach , 7th ed., section 1.3.1). That sentence leaves three questions open: Why does the router wait? What does it do w...