Consider a packet of length l, which begins at source and travels over seven links to a destination. these links are connected through six routers. let di, si, and ri denote the length, propagation speed, and the transmission rate of link i, for i = 1 to 7. the processing delay at each router is d-proc. the queuing delay at each router is d-que. what is the total end-to-end delay for the packet in terms of di, si, ri (i = 1 to 7), and l?