A Test Request (tag 35-MsgType=1) message is sent to ensure connectivity. This message can be sent by both the client system and CME Globex.
If connectivity is in question, for example, a Heartbeat (tag 35-MsgType=0) message has not been received at the defined interval, the following should occur:
- A Test Request (tag 35-MsgType=1) message is sent.
- A Heartbeat (tag 35-MsgType=0) message is sent in response with tag 112-TestReqID from the original Test Request message.
- If no Heartbeat (tag 35-MsgType=0) message is received in response to the Test Request (tag 35-MsgType=1) message within the defined hearbeat interval, the connection is assumed to be stale and the socket is closed.
- If the connection being closed is the primary connection and the client employs fault tolerance, iLink 2 initiates a failover process to make one of the backup connections, if existent, the new primary.
- If the client does not employ fault tolerance, CME Globex updates the status of that client to 'logged out'.
- A Test Request (tag 35-MsgType=1) message is sent only to ensure connectivity, and as a handshake
upon logon.
The following diagram illustrates the successful Test Request (tag 35-MsgType=1) message flow.
