Consider the router diagram. Consider that the packets shown are uniformly 500kB in size and that they are all stored in the input buffers of ports W, X and Y. These packets marked with the output buffer they are destined for. The switching fabric is a crossbar based design with each crossbar bus operating at 10Mbps.
a) How much time is required to move all the packets from the input port buffers to the output port buffers? Does Head of Line blocking occur?
b) If all the packets in the input port buffer for X are now 1500kB in size but the others remain unchanged. How much time is required to move all the packets to the output port buffers? Does Head of Line blocking occur?
c) How did the variable packet sizes affect the time required to move the packets through the switching fabric?
d) Consider the scenario in part b) but if the router instead "fragmented" each of the larger 1500kB packets into 3 smaller 500kB cells. Assume that these fragmented pieces can be put back together in the output port buffer even if they pass through the fabric out-of-order. How much time is required to move all the packets to the output port buffers?