Question: In GTPv1-U, when constructing an Echo Response Message, how are the UDP Source and Destination Ports determined in relation to the corresponding Echo Request Message?
Option 1: The UDP Source and Destination Ports are randomly generated for each response.
Option 2: The UDP Source Port is incremented by one from the UDP Source Port of the request, while the UDP Destination Port remains unchanged.
Option 3: The UDP Source and Destination Ports swap values with the previous response message's ports.
Option 4: The UDP Destination Port value is set to the UDP Source Port of the request, and the UDP Source Port is set to the UDP Destination Port of the request.
Explanation: This is correct because, according to specifications for GTPv1-U Echo Response Messages, the ports are swapped from their values in the corresponding Echo Request Message. This ensures responses are properly routed back to the request originator, utilizing port numbers as identifiers for the communication flow, crucial for maintaining connectivity and ensuring message delivery to the intended endpoint within telecom networks.