Question: In a network supporting validation of Priority Uplink Requests, what happens to both tokens (A and B) in the Base Station Subsystem when a valid Priority Uplink Request is received before timer Ttv expires?
Option 1: Only token A is invalidated, and token B remains active.
Option 2: Both tokens (A and B) are invalidated, and timer Ttv is stopped.
Option 3: Token B replaces Token A, with no immediate invalidation of either.
Option 4: The validity of both tokens is extended until the next UPLINK_BUSY message.
Explanation: This outcome ensures security and prevents potential misuse by immediately invalidating both the unused token (A) from the previous period and the new token (B) sent with the uplink busy message, once a valid Priority Uplink Request is successfully matched and processed within the Ttv timeframe. This mechanism maintains the integrity of the validation process for Priority Uplink Requests in Voice Group Call Services.