Four towns A, B, C and D are connected in a telephone network as shown in the

above figure. Traffic between these 4 towns (in Erlangs) is given in the table below.

A B C D

A – 10 10 40

B 15 – 5 5

C 10 5 – 10

D 30 10 5 –

Assuming that the end-to-end GoS blocking probability should be less than 1%,

calculate the number of trunks required for trunk groups A-C, C-D and B-C.

Note: Assume that the GoS blocking probability for all trunk groups (A-C, C-D, B-C)

is the same.

Due to the high traffic volume between towns A and D, the network planners have

decided to put a direct trunk group of 36 trunks between these two towns. To

compensate the cost of these additional trunks, network planners have also decided to

reduce the number of trunks between A-C and C-D by 37 trunks each. The new

routing policy is to route traffic between A and D using the direct trunk group and

once the direct trunk group is full, any incoming traffic (between towns A and D) are

routed via C. Calculate the blocking probabilities between A-D and B-D.

Note: Assume that the combination of overflow and offered traffic to any trunk group

is Poisson.

plz help me to solve this sum