Test Request (MsgType = 1)

The Test Request (1) message forces a heartbeat from the opposing application. The Test Request (1) message checks sequence numbers or verifies communication line status. The opposite application responds to the Test Request (1) with a Heartbeat (0) containing the TestReqID (112) .

The TestReqID (112) verifies that the opposite application is generating the heartbeat as the result of Test Request (1) and not a normal timeout. The opposite application includes the TestReqID (112) in the resulting Heartbeat (0) . Any string can be used as the TestReqID (112) (one suggestion is to use a timestamp string).