Consider a network with three routers P, Q, R shown in the figure below. All the links have cost of unity.
The routers exchange distance vector routing information and have converged on the routing tables, after which the link Q−R fails. Assume that P and Q send out routing updates at random times, each at the same average rate. The probability of a routing loop formation (rounded off to one decimal place) between P and Q, leading to count-to-infinity problem, is___________.

A

1

Question 10 Explanation:

If asked for R, Probablity = 1
If asked for R, from among P, Q, R
Probability = 1 /3

Correct Answer: A

Question 10 Explanation:

If asked for R, Probablity = 1
If asked for R, from among P, Q, R
Probability = 1 /3