In this illustration, two computers are sending packets to a central router labeled A. The packets are queued inside and then transmitted to a second router, labeled B. In this view, router A is divided in half; the left side, which is empty, is labeled "Nodal processing," while the right side, which contains several packets, is labeled "Queuing (waiting for transmission)." One packet is just outside of the router with a blue line pointing rightward towards router B along a black line indicating its path. This area just to the right of router A is labeled "Transmission." The rest of the black line between router A and router B is labeled "Propagation."