TT® FIX

Logon (A) Message

Purpose

Used to establish a connection between a FIX client and TT FIX

Message Direction

From TT FIX to FIX client and from FIX client to TT FIX

Supported Tags

Tag # Field Name Req’d Data Type Comments
Component Block <Standard Header> Y 35=A (MsgType)
96 RawData C data

Logon password

The value must match the logon password for the FIX session. TT FIX does not include this tag in its responses.

Condition: Required in FIX client requests.

98 EncryptMethod Y int

Method of encryption

As TT FIX does not support encrypted logons, you must set the value to 0 (None/Other).

108 HeartBtInt Y int

Heartbeat interval (seconds)

141 ResetSeqNumFlag N Boolean

Whether to reset the sequence numbers on both sides of the FIX session

Valid values include Y and N (default).

Notes:

  • If a FIX client sends Y, it must also set tag 34 (MsgSeqNum) = 1.
  • For Security Definition sessions, FIX clients must always set 141=Y and 34=1.
Component Block <Standard Trailer> Y

Message Notes

The Logon (A) message is used by a FIX client to begin a new or continue an existing session with TT FIX.

Note: When logging in to a Security Definition FIX session, a FIX client must always set 141=Y and 34=1; otherwise, TT FIX sends a Logout (5) message with the message: "MsgSeqNum must be set to 1 if ResetSeqNumFlag is set to Y" in tag 58 (Text).

The following data flow illustrates a typical logon sequence between TT FIX and a FIX client for an order session:

  1. FIX client initiates a socket connection.
  2. FIX client sends a Logon (A) message to TT FIX.
  3. TT FIX receives the FIX client logon message and verifies the following tags in the Logon (A) message against the corresponding parameter values:
    • Tag 56 (TargetCompID) to LocalCompId (in TT User Setup)
    • Tag 96 (RawData) to Password (in TT User Setup)
  4. If any of the following errors occur, TT FIX stops processing the logon attempt, sends the FIX Client a Logout (5) message with the reason for rejection in Tag 58 (Text), and closes the socket connection.
    • These tags do not match for the adapter and the client.
    • TT User Setup does not respond.
    • The TT universal login credentials (tags 49 and 96) are invalid.
  5. Examine the value of Tag 141 (ResetSeqNumFlag).
  6. If Tag 141 (ResetSeqNumFlag) is set to N, TT FIX compares the value of Tag 34 (MsgSeqNum) in the Logon (A) message against its current sequence number.

    • If MsgSeqNum is less than the expected sequence number, TT FIX stops processing the logon attempt, sends a Logout (5) message as its response, and closes the socket connection.
    • If MsgSeqNum is greater than sequence number TT FIX expected, the logon process continues normally. However, after the logon process completes, TT FIX sends a Resend Request (2) message.

    If Tag 141 (ResetSeqNumFlag) is set to Y, TT FIX expects the value of Tag 34 (MsgSeqNum) in the Logon (A) message to be 1.

    • If Tag 34 is not 1, TT FIX stops processing the logon attempt, sends a Logout (5) message, and closes the connection.
    • Otherwise, the logon process continues normally.
  7. TT FIX sends a Logon (A) message to the FIX client.