Consider this network topology:

A ---> S -----> B

with two hosts (A and B) and a switch S that uses store and forward technique.

Use this notation:

d(x,y) = distance between nodes x and y -------- v = signal propagation speed -------- N = packet length, in bytes -------- T_q(x) = queuing delay at node x. Assume for all nodes x that T_q(x) 0. -------- R = data rate, same for all links, in bps

* Write the formula for T_AB, the delay between the transmission of the first bit of a packet at A and the reception of its last bit at the destination, B.

*What is the formula for T_AB if the topology changes to one where between A and B there are n switches with identical T_q, all link data rates are equal to R, and all link lengths are equal to d ?

A -----> S1 -----> S2 -----> .......... -----> Sn -----> B

*A network designer has to select a technology for the topology from part b) with the proper minimum data rate R_min so that T_AB T_max, for a given T_max. Determine the formula for R_min as a function of all other parameters, including n and T_max.