Session Messages By MsgType

Name Description
(0) Heartbeat

The Heartbeat (0) monitors the status of the communication link and identifies when the last of a string of messages was not received.

(1) Test Request

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) .

(2) Resend Request

The Resend Request (2) is sent by the receiving application to initiate the retransmission of messages. This function is utilized if a sequence number gap is detected, if the receiving application lost a message, or as a function of the initialization process.

(3) Reject

The Reject (3) message should be issued when a message is received but cannot be properly processed due to a session-level rule violation. An example of when a reject may be appropriate would be the receipt of a message with invalid basic data (e.g. MsgType (35) =&) which successfully passes de-encryption, CheckSum (10) and BodyLength (9) checks. As a rule, messages should be forwarded to the trading application for business level rejections whenever possible.

(4) Sequence Reset

The Sequence Reset (4) message has two modes: Gap Fill mode and Reset mode.

(5) Logout

The Logout (5) message initiates or confirms the termination of a FIX session. Disconnection without the exchange of Logout (5) messages should be interpreted as an abnormal condition.

(A) Logon

The Logon (A) message authenticates a user establishing a connection to a remote system. The Logon (A) message must be the first message sent by the application requesting to initiate a FIX session.