We are porting FreeRTOS on Pxa303 board, we want to establish ethernet communication between 2 pxa303 boards. We are using FreeRTOS+UDP(FreeRTOSV7.4.1\FreeRTOS-Plus\Source\FreeRTOS-Plus-UDP) for this purpose, twoechoclients.c(FreeRTOSV7.4.1\FreeRTOS-Plus\Demo\Common\FreeRTOS_Plus_UDP_Demos\EchoClients\) as a client applicaion, as mentioned at http://www.freertos.org/FreeRTOS-Plus/FreeRTOS_Plus_UDP/Embedded_Ethernet_Examples/Common_Echo_Clients.shtml, website suggests desktop computer to use as a server, but we want another pxa303 board to be used as a server. Can any one guide us with how to program a server application for Pxa303 board?

FreeRTOS+UDP uses a standard (ish) sockets interface, so the procedure is as per using any other Berkeley sockets IP stack:

1) Call FreeRTOS_socket() to create a socket - it will be created with a receive block time of portMAX_DELAY.
2) Call FreeRTOS_bind() to bind the socket to the echo port (port 7 by default).
3) Call FreeRTOS_recvfrom() on the socket. If configINCLUDE_vTaskSuspend is set to 1 the call will only return once data has been received.
4) Call FreeRTOS_sendto() to send the received data back from whence it came.
5) Go back to step 3 to wait for more data.

It would look something like this (I have not tried running this code! It is for example only)

static void prvEchoServer( void *pvParameters )
{
xSocket_t xSocket;
struct freertos_sockaddr xAddress;
/* Make sure array is large enough and that it does not overflow the
task stack.  Make it static if necessary. */
int8_t cBuffer[ 25 ];
uint32_t xAddressLength = sizeof( xAddress );
long lBytes;

  /* Remove compiler warning about unused parameters. */
  ( void ) pvParameters;

  for( ;; )
  {
    /* Create a socket. */
    xSocket = FreeRTOS_socket(  FREERTOS_AF_INET,
                                FREERTOS_SOCK_DGRAM,
                                FREERTOS_IPPROTO_UDP );

    /* Bind the the standard echo server port number. */
    xAddress.sin_port = FreeRTOS_htons( echoECHO_PORT );
    FreeRTOS_bind( xSocket, &xAddress, sizeof( xAddress ) );

    /* Send a number of echo requests. */
    for( ;; )
    {
      /* Wait for data to arrive on the echo port. */
      lBytes = FreeRTOS_recvfrom( xSocket, cBuffer, sizeof( cBuffer ),
                                    0, &xAddress, &xAddressLength );

      /* Send the received data back from the originating address. */
      FreeRTOS_sendto( xSocket, cBuffer, lBytes, 0,
                          &xAddress, xAddressLength );
    }
  }
}

Regards.