1. What is an SCP? What are its functions? Explain how do we use SCP to implement virtual calling card facility? 2. What is number portability? How is number portability different from telephone...

1. What is an SCP? What are its functions? Explain how do we use SCP to implement virtual calling card facility?

2. What is number portability? How is number portability different from telephone portability?

3. What are supplementary services? Explain with few examples.