The test request message forces a heartbeat from the opposing application. The test request message checks sequence numbers or verifies communication line status. The opposite application responds to the Test Request with a Heartbeat containing the TestReqID.
The TestReqID verifies that the opposite application is generating the heartbeat as the result of Test Request and not a normal timeout. The opposite application includes the TestReqID in the resulting Heartbeat. Any string can be used as the TestReqID (one suggestion is to use a timestamp string). The test request format is as follows.
Table 7 – Test Request
|
Tag |
Field Name |
Req’d |
Comments |
Format |
|
Standard Header |
Y |
MsgType = 1 |
| |
|
112 |
TestReqID |
Y |
|
String |
|
Standard Trailer |
Y |
|
| |