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
Tag Directory
Click the links below to navigate to the documentation for that tag.
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:
- The TT FIX Gateway opens a socket connection to the third-party FIX acceptor.
- The TT FIX Gateway sends a Logon (A) message to the third-party FIX acceptor.
- 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.
- 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.
- 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.
