Question: What happens to an existing Logical Link Control (LLC) connection when a Mobile Station (MS) moves from a cell served by one Serving GPRS Support Node (SGSN) to a cell served by a different SGSN?
Option 1: The LLC connection is maintained, and the MS's new location is updated with the original SGSN.
Option 2: The existing LLC connection is released, and a new logical connection is established with the new SGSN.
Option 3: The LLC layer automatically negotiates new protocol timer values before deciding on the next course of action.
Option 4: The MS temporarily loses data link ciphering until it re-establishes contact with the original SGSN.
Explanation: When an MS moves to a cell served by a different SGSN, the infrastructure cannot maintain the continuity of the logical link control connection due to the change in serving network elements. Thus, the existing connection must be terminated, and a new one set up with the new SGSN to ensure seamless service continuation, highlighting the importance of session management in mobile networks.