Problem
Consider a short, 10 meter link, over which a sender can transmit at a rate of 150 bits / sec in both directions. Suppose that packets containing data are 100,000 bits long, and packets containing only control (e.g., ACK or handshaking) are 200 bits long. Assume that N parallel connections each get l/N of the link bandwidth. Now consider the HTTP protocol, and suppose that each downloaded object is 100 Kbits long, and that the initial downloaded object contains 10 referenced objects from the same sender. Note that the HTTP GET can "piggyback" on the third packet of the TCP handshake.
1. Consider using parallel downloads via parallel instances of non-persistent HTTP, versus using persistent HTTP. ls persistent HTTP significantly better in this case?
2. Now consider that the Web transfer described above is performed by one user (Bob) and that Bob is sharing the network with four other users who also want to perform a similar Web transfer. Bob uses parallel instances of non-persistent HTTP, and the other four users using non-persistent HTTP without parallel downloads. Do Bob's parallel connections help him get Web pages more quickly? Explain why or why not.
3. If all five users use five parallel instances of non-persistent HTTP, then are Bob's parallel connections still beneficial to him?