Section: 4.2.1.2 Triggered Messages
Content: The UDP Destination Port value of a GTPv2 Triggered message and for a Triggered Reply message shall be the value of the UDP Source Port of the corresponding message to which this GTPv2 entity is replying, except in the case of the SGSN pool scenario. The UDP Source Port of a GTPv2 Triggered message and for a Triggered Reply message shall be the value from the UDP Destination Port of the corresponding message to which this GTPv2 entity is replying, except in the case of the SGSN pool scenario. In the SGSN pool scenario, if the Identification Request, the Context Request or the Suspend Notification messages have been forwarded by another SGSN in the pool, the UDP Destination Port for the Identification Response, the Context Response or the Suspend Acknowledge message shall be determined in the following way. The value from the information element "UDP Source Port Number", which was sent in the corresponding forwarded request, shall be copied into the UDP Destination Port field. The UDP Source Port for the Identification Response, the Context Response or the Suspend Acknowledge message may be a locally allocated port number at the sending GTP entity. In the handover scenario when the CIoT feature is deployed, if the Forward Relocation Request message has been forwarded by the target MME, the UDP Destination Port for the Forward Relocation Response shall be set to the value of Source UDP Port Number IE included in the Forward Relocation Request message; the UDP Source Port for the Forward Relocation Response message may be a locally allocated port number at the sending GTP entity.