Question: What is the primary purpose of a Handover Number in telecom networks, specifically between Mobile Switching Centers (MSCs)?
Option 1: To uniquely identify User Equipment (UE) during initial network attachment
Option 2: For authentication and security key exchange between the UE and MSC
Option 3: For establishing a circuit between MSCs for a handed-over call
Option 4: To manage Quality of Service (QoS) parameters for ongoing sessions
Explanation: The correct answer, Option 3, highlights the Handover Number's role in facilitating the handover process by establishing a necessary circuit between different Mobile Switching Centers (MSCs) to ensure seamless call continuity. This is crucial in telecom networks for maintaining active calls when a user moves from one geographical area to another, transitioning between the coverage areas of different MSCs. The other options are incorrect because they describe unrelated processes: UE identification (Option 1), security protocols (Option 2), and QoS management (Option 4).