Question: What is a key characteristic of some numbering schemes in the CS CN (Circuit Switched Core Network) domain, particularly in relation to user mobility between networks?
Option 1: They must always be tied to the serving network's geographic location.
Option 2: They can be fully independent of the supporting serving network and home environment, allowing for easy transfer.
Option 3: They are exclusively allocated from a global numbering scheme to ensure universality.
Option 4: They require a change in MSISDN when a user moves to a new home environment in a different region.
Explanation: This correct answer highlights the flexibility designed into some numbering schemes, enabling seamless user transitions between different service providers (home environments) without the necessity of changing their phone number (MSISDN), provided the move is within the same geographic domain. This feature supports mobile number portability (MNP), enhancing user convenience and continuity of service.