Ben Bitdiddle has accepted a job with the telephone company and has been asked to implement call
Question:
Ben Bitdiddle has accepted a job with the telephone company and has been asked to implement call forwarding. He has been pondering what to do if someone forwards calls to some number and then the owner of that number forwards calls to a third number. So far, Ben has thought of two possibilities for his implementation:
a. Follow me. Bob is going to a party at Mary’s home for the evening, so he forwards his telephone to Mary. Ann is baby-sitting for Bob, so she forwards her telephone to Bob. Jim calls Ann’s number, Bob’s telephone rings, and Ann answers it.
b. Delegation. Bob is going to a party at Mary’s home for the evening, so he forwards his telephone to Mary. Ann is gone for the week and has forwarded her telephone to Bob so that he can take her calls. Jim calls Ann’s number, Mary’s telephone rings, and Mary hands the phone to Bob to take the call.
c. Using the terminology of the naming section of this chapter, explain these two possibilities.
d. What might go wrong if Bob has already forwarded his telephone to Mary before Ann forwards her telephone to him?
e. The telephone company usually provides Delegation rather than Follow me. Why?
Step by Step Answer:
Principles Of Computer System Design An Introduction
ISBN: 9780123749574
1st Edition
Authors: Jerome H. Saltzer, M. Frans Kaashoek