Question: What is the purpose of including a "Session Stop indicator" in the Accounting-Request STOP message sent by the GGSN/P-GW?
Option 1: To indicate that the IP-CAN session has started.
Option 2: To request the allocation of an IPv4 address.
Option 3: To avoid race conditions and ensure the AAA server does not assume the IP-CAN session is terminated prematurely.
Option 4: To inform the accounting server about the allocated IPv6 prefix.
Explanation: The "Session Stop indicator" is included in the Accounting-Request STOP message to prevent the AAA server from assuming the IP-CAN session has been terminated before all IP-CAN bearers have been stopped, thus avoiding potential race conditions.