1. System A consists of a single ring with 100 stations, one per repeater. System B consists of four 25 stations rings linked by a bridge. If the probability of a link failure is P1, a repeater failure is Pr, and a bridge failure is Pb, derive an expression for parts (a) to (e).
a) Probability of failure of system A.
b) Probability of complete failure of system B.
c) Probability that a particular station will find the network unavailable, for systems A and B.
d) Probability that any two stations selected at random will be unable to communicate for systems A and B.
e) Compare values of parts (a) and (b) for Pl = Pb = Pr = 10-2.
2. We send a frame of 256 bits. If the probability that a bit changes in transmission is 0.001 and each bit is independent.
a. What is the probability that exactly 6 bits change?
b. What is the probability of no bits changing?
3. If a Signal with a power level of 40 mW is inserted onto a transmission line and the measured power some distance away is 10 mW, calculate the loss of signal strength is decibels.