Not all command line switches are optional.
While most of the command line switches described in Utility Guide > Running the Database Server are optional, you must specify the -n switch to run Sybase IQ effectively.
If you use TCP/IP to connect to the server, you should include network connection parameters as well. If you start the server without the parameter -x 'tcpip(port=nnnn)' set, then the server uses the default TCP/IP port number 2638. If you specify a port number that is already in use, the server fails to start.