Question: What is the rule for determining the UDP Destination Port value of a GTPv2 Triggered message and a Triggered Reply message, except in the case of the SGSN pool scenario?
Option 1: The UDP Destination Port value shall be the same as the UDP Source Port of the corresponding message to which this GTPv2 entity is replying.
Option 2: The UDP Destination Port value shall be a locally allocated port number at the sending GTP entity.
Option 3: The UDP Destination Port value shall be determined by the receiving GTP entity.
Option 4: The UDP Destination Port value shall be set to a default value of 2123.
Explanation: According to the text, in general cases (except for SGSN pool scenario), the UDP Destination Port value of a GTPv2 Triggered message and a Triggered Reply message is determined by the UDP Source Port of the corresponding message to which this GTPv2 entity is replying.