The bridge learning process improves performance: A unicast frame whose destination has been learned is forwarded only through the port that leads to the destination—it does not get sent onto other parts of the LAN.
An administrator can enter static information that reduces unnecessary unicast traffic even further.
Stemming the flow of multicast frames is another challenge. According to the original rule of multicasting, if even one station on a LAN joins a multicast group, every station on the LAN will see all the frames sent to that multicast group. As multicast applications become more prevalent, following this rule will undo the efficiencies that have carefully been built into the new switch devices.