Microchip TCPIP keep alive not works - tcp

Question

i'm trying to build a server with a PIC24F.
This is a piece of code i'm isuing:
switch(TCPServerState) {
case SM_HOME:
// Allocate a socket for this server to listen and accept connections on
socket.Socket = TCPOpen(0, TCP_OPEN_SERVER, SERVER_PORT, TCP_PURPOSE_GENERIC_TCP_SERVER);
if(socket.Socket != INVALID_SOCKET) {
TCPServerState = SM_LISTENING;
}
break;
case SM_LISTENING:
// See if anyone is connected to us
//if(TCPIsConnected(socket.Socket)) {
if(!TCPWasReset(socket.Socket)){
if(socket.Connected == 0) {
socket.Connected = 1;
printf("Socket is CONNECTED: %d\n", socket.Socket);
}
uint16_t avaible = TCPIsGetReady(socket.Socket);
// Some stuff
}
else if(socket.Connected == 1){
printf("Socket RESET: %d\n", socket.Socket);
TCPServerState = SM_CLOSING;
}
break;
case SM_CLOSING:
// Close the socket connection.
socket.Connected = 0;
TCPClose(socket.Socket);
TCPServerState = SM_HOME;
printf("Socket is CLOSED: %d\n", socket.Socket);
break;
}
All works fine if i close my client socket properly, but if i disconnect ethernet cable i am not able to detect disconnection and my code does not close the socket because TCPWasReset still FALSE(or TCPIsConnected still TRUE).
So how can i detect the disconnection of network cable(without add a software keep_alive implementation) ?
Thanks

Answer 1

Check a few items:
Call TickInit(); before StackInit();
Select the correct TIMER1 clock source for your application - internal clock or external clock (T1CON.TCS)
Otherwise, just use a debugger on the keepalive logic in TCP.C, which should default to 10 seconds in the latest Microchip Library for Applications TCP/IP stack 5.42.08.