The present invention relates to switching technology, such Ethernet, where data switching is performed based on a collision-prone switching table (31). The invention provides a possibility to avoid difficult collision-caused flooding and makes it possible to use simple and inexpensive switching equipment, while still not having to worry about consequences of collision-caused flooding. A preferred destination list (43) is provided. This list identifies one or more preferred switching destinations (1, 11). For each preferred destination, a switching address and a corresponding port identification is obtained (53). An order (55) is then made to enter and lock the obtained switching address and corresponding port identification into the switching table (31).