Session States

During the FIX session lifetime it could be in one of the following states:

State	Session-Acceptor	Session-Initiator
Disconnected	The session is disconnected	The session is disconnected
AwaitLogon	The session is waiting for the initial Logon message	Not applicable (Initiator cannot be in this state)
AwaitConfirmingLogon	Not applicable (Acceptor cannot be in this state)	The initial Logon message was sent and the session is waiting for the acknowledgment Logon message
Established	The session is fully established (after the successful Logon exchange)	The session is fully established (after the successful Logon exchange)
Reconnecting	Not applicable (Acceptor cannot be in this state)	Session is trying to restore the telecommunication link
WaitForRetransmission	A message gap occurred, and the session waits for resent messages/gap fills	A message gap occurred, and the session waits for resent messages/gap fills
AwaitConfirmingLogout	The initial Logout message was sent, the session is waiting for the acknowledgment Logout message	The initial Logout message was sent, the session is waiting for the acknowledgment Logout message

The State property could be used to check the session's current state.

Initiator Session State Diagram

Acceptor Session State Diagram

Tracking Session State Changes

The Session class exposes the StateChanged event. Subscribing to this event provides the ability to be notified about all changes in the state of the source session.

For example:

var session = new Session("SenderCompID", "TargetCompID", ProtocolVersion.Fix44);
session.StateChanged += OnStateChanged;

void OnStateChanged(object sender, SessionStateChangeEventArgs e)
{
    Console.WriteLine("Session {0} changed its state from {1} to {2}.", sender, e.PrevState, e.NewState);
}