methods , systems and computer program products that control the data rate through a communications adapter having at least one guaranteed bandwidth connection through the communications adapter are provided . the data rate is controlled by assigning to the guaranteed bandwidth connection , a maximum threshold value proportional to the amount of data to be transmitted through the communications adapter in a time interval to satisfy the guaranteed bandwidth of the connection . the amount of data transmitted through the communications adapter for the guaranteed bandwidth connection is then counted so as to provide a connection data count associated with the guaranteed bandwidth . data transmitted for the communications adapter associated with the guaranteed bandwidth connection is not transmitted to the communications adapter if transmission of the data would cause the connection data count to exceed the maximum threshold value assigned to the guaranteed bandwidth connection . the connection data count is then reset after expiration of the time interval .