Ethernet Developers Guide
B.10 Transmit State Machine
The transmit state machine establishes a connection, and periodically transmits a request. The different states for the transmit state machine are as follows.
IDLE. In the IDLE state, there is no connection.
RESOLVING_NAME. In the RESOLVING_NAME state, CSample_View is waiting for the window socket DLL to convert a node’s name into an IP address.
CONNECTING. In the CONNECTING state, CSample_View is waiting for the window socket DLL to generate the FD_CONNECT event. This event indicates if the attempt to establish a connection succeeded or failed.
CONNECTED. The CONNECTED state indicates that a connection has been successfully established.
WAIT_TO_TX. In the WAIT_TO_TX state, CSample_View is waiting to transmit the message. It transmits the message, when the time from the last
ztransmit exceeds the specified poll interval.
BLOCKED. When CSample_View attempts to send a message, the window socket DLL may not be able to transmit the complete message. This is a flow control condition, and CSample_View enters the BLOCKED state. The window socket DLL generates the FD_WRITE event when it can send more
zdata.
TX_DONE. CSample_View enters the TX_DONE when it has completed transmitting the request.
If the CSample_View is in the IDLE state, and user selects either the connect menu item, or the connect tool bar button, CSample_View OnManagConnect function attempts to establish connect with its tcpip_initate_connection function. This function examines the remote destination and determines if it’s a name or an IP address. If it’s a name, OnMangConnect changes the transmit state to RESOLVING_NAME, and it invokes the window sockets DLL WSAAsyncGetHostByName function to resolve the name. Window sockets DLL will generate the user defined WM_TCPIP_NAME_RESOLVED message which indicates if the name has been resolved. The OnTcpIpNameResolved member function process the WM_TCPIP_NAME_RESOLVED message. If the name is not resolved, OnTcpIpNameResolved changes the transmit state back to IDLE.
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