In OpenERP rpc help to change the post, like user want to excute two server in same systems then use rpc and change port number of other server. Basically rpc is used to run server in local systems.

Use this function given below

def rpc(service_name, method, params):

    try:
        rpc_request = logging.getLogger(__name__ + '.rpc.request')
        rpc_response = logging.getLogger(__name__ + '.rpc.response')
        rpc_request_flag = rpc_request.isEnabledFor(logging.DEBUG)
        rpc_response_flag = rpc_response.isEnabledFor(logging.DEBUG)
        if rpc_request_flag or rpc_response_flag:
            start_time = time.time()
            if rpc_request and rpc_response_flag:
                log(rpc_request,logging.DEBUG,'%s.%s'%(service_name,method), replace_request_password(params))

        result = ExportService.gedef dispatch_rpc(service_name, method, params):

    try:
        rpc_request = logging.getLogger(__name__ + '.rpc.request')
        rpc_response = logging.getLogger(__name__ + '.rpc.response')
        rpc_request_flag = rpc_request.isEnabledFor(logging.DEBUG)
        rpc_response_flag = rpc_response.isEnabledFor(logging.DEBUG)
        if rpc_request_flag or rpc_response_flag:
            start_time = time.time()
            if rpc_request and rpc_response_flag:
                log(rpc_request,logging.DEBUG,'%s.%s'%(service_name,method), replace_request_password(params))

        result = ExportService.getService(service_name).dispatch(method, params)

        if rpc_request_flag or rpc_response_flag:
            end_time = time.time()
            if rpc_response_flag:
                log(rpc_response,logging.DEBUG,'%s.%s time:%.3fs '%(service_name,method,end_time - start_time), result)
            else:
                log(rpc_request,logging.DEBUG,'%s.%s time:%.3fs '%(service_name,method,end_time - start_time), replace_request_password(params), depth=1)

        return result
    except openerp.exceptions.AccessError:
        raise
    except openerp.exceptions.AccessDenied:
        raise
    except openerp.exceptions.Warning:
        raise
    except openerp.exceptions.DeferredException, e:
        _logger.error(tools.exception_to_unicode(e))
        post_mortem(e.traceback)
        raise
    except Exception, e:
        _logger.error(tools.exception_to_unicode(e))
        post_mortem(sys.exc_info())
        raise

tService(service_name).dispatch(method, params)

        if rpc_request_flag or rpc_response_flag:
            end_time = time.time()
            if rpc_response_flag:
                log(rpc_response,logging.DEBUG,'%s.%s time:%.3fs '%(service_name,method,end_time - start_time), result)
            else:
                log(rpc_request,logging.DEBUG,'%s.%s time:%.3fs '%(service_name,method,end_time - start_time), replace_request_password(params), depth=1)

        return result
    except openerp.exceptions.AccessError:
        raise
    except openerp.exceptions.AccessDenied:
        raise
    except openerp.exceptions.Warning:
        raise
    except openerp.exceptions.DeferredException, e:
        _logger.error(tools.exception_to_unicode(e))
        post_mortem(e.traceback)
        raise
    except Exception, e:
        _logger.error(tools.exception_to_unicode(e))
        post_mortem(sys.exc_info())
        raise