FIX Gateway

Logon (A) Message

Purpose

Used to establish a connection between a TT FIX Gateway and a third-party FIX acceptor

Message Direction

From TT FIX Gateways to a third-party FIX acceptor and then from a third-party FIX acceptor to TT FIX Gateways

Supported Tags

Tag # Field Name Req’d Data Type Comments
Component: Standard Header Y 35=A (MsgType)
96 RawData C String

Logon password

Condition: Will be sent when the TT FIX Gateway initiates a connection. The third-party FIX acceptor need not send this in the response.

98 EncryptMethod Y int

Method of encryption

As TT FIX Gateway 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).

Component: Standard Trailer Y

Message Notes

The Logon (A) message is used by a TT FIX Gateway to begin a new or continue an existing session with a third-party FIX acceptor.

The following data flow illustrates a typical logon sequence between a TT FIX Gateway and a third-party FIX acceptor:

  1. The TT FIX Gateway opens a socket connection to the third-party FIX acceptor.
  2. The TT FIX Gateway sends a Logon (A) message to the third-party FIX acceptor.
  3. If the third-party FIX acceptor detects any errors, it will respond with a Logout (5) message with the reason for rejection in Tag 58 (Text), and closes the socket connection.
  4. The third-party FIX acceptor examines the value of Tag 141 (ResetSeqNumFlag).
    • If Tag 141 (ResetSeqNumFlag) is set to N, the third-party FIX acceptor 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, the third-party FIX acceptor 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 the third-party FIX acceptor expected, the logon process continues normally. However, after the logon process completes, the third-party FIX acceptor sends a Resend Request (2) message.
    • If Tag 141 (ResetSeqNumFlag) is set to Y, the third-party FIX acceptor expects the value of Tag 34 (MsgSeqNum) in the Logon (A) message to be 1.
      • If Tag 34 is not 1, the third-party FIX acceptor stops processing the logon attempt, sends a Logout (5) message, and closes the connection.
      • Otherwise, the logon process continues normally.
  5. The third-party FIX acceptor sends a Logon (A) message to the TT FIX Gateway.

TT FIX Price Gateway

The TT FIX Price Gateway will only support non-persistent FIX sessions. In other words, it will always send a Logon (A) message with Tag 34 (MsgSeqNum)=1 and Tag 141 (ResetSeqNumFlag)=Y when initiating a connection. As a result, the FIX session will terminate when the connection does.

TT FIX Order Gateway

When the TT FIX Order Gateway is started for the first time, it will send a Logon (A) message with Tag 34 (MsgSeqNum)=1. When there are unscheduled restarts, the standard FIX message sequence number negotiation will take place. After scheduled message sequence number resets, the TT FIX Order Gateway will send a Logon (A) message with Tag 34 (MsgSeqNum)=1.