A more ambitious problem is the following. Assume that the population of Anagon is 20, Bregen is 15, and Charmes is 25. Further assume that each employee calls both other sites 5 times a day and talks for an average of 5 minutes. Engineer the interoffice trunks among the 3 locations. There will be 3 groups of point-to-point trunks and 3 groups of trunks into the PSTN. Assume blocking is limited to 0.5%.

2.5. Use the populations of Anagon, Bregen, and Charmes given in Exercise 2.4 and the same call volumes. Now assume that there are only 2 trunk groups, Anagon to Bregen and Bregen to Charmes. Assume that the Anagon-to-Charmes traffic is carried by 2 links in tandem that are switched at Bregen. Assume that you can add the traffic in Erlangs.

Then size the 2 links so that the blocking is less than 0.5%. If you have completed the previous problem, which design is cheaper?