In the last decade we have experienced huge changes in the way we communicate. We have moved from fixed and wired plain old telephone service (POTS) to briefcase-sized mobile phones, and more recently to smartphones. Behind the scenes we have moved seamlessly from the circuit switched technology of the public switched telephone network (PSTN) and early cellular networks to the packet switched technologies of the Internet. The growth in user services has placed pressure on service providers to support new applications while maintaining their traditional quality. Read this paper to learn more.