Question

Consider a packet switching network. Packets from origin host travel over H hops to reach the destination host. Supppose that the origin host wants to transmit a message that is M bits long. The bit rate of all links is C (bits/sec), and the propoagation delay over every link is D seconds. The message will be broken into packets. Suppose that each packet has a constant overhead of V bits. Let L be the fixed payload of each packet. Thus, the number of packets that the message will be broken into is roughly M=L (you may assume that this number is an integer).

Find the total delay until all packets are delivered at the destination host. (5 points)

Find the value of L that minimizes the delay you found in part (a). (5 points)

Answer 1

a) H-origin host M-size of message D- Linkpropagation delay Packet transition delay- size of message /Link propagation delay T-MD V-constant overhead L-fixed payload of each packet. Total delay-totalpropagation +total transmission +total store and forward+ total processing Total delay = HD MT-CH-1) T-CH-1) L b) Fixed payload is a value of delay that minimizes the total delay of hopes sent