In frame switched communication networks, information is forwarded from a source to a destination based on a destination address. In IEEE 802 networks these addresses are called Media Access Control (MAC) addresses. MAC addresses identify the source and destination station of each frame, however typically don't contain any subfields which identify the physical or logical location (or subnetwork) of the station. Such an address can be called a flat address. The entities of networks using IEEE 802 MAC addresses don't have methods for aggregating MAC addresses or for forwarding frames based on aggregates rather than station MAC addresses. The use of station MAC addresses for frame forwarding limits the scaling, lowers the efficiency, reduces the security and raises the cost of these networks. The method described here solves the MAC address aggregation problem by using a summary MAC address to represent an aggregate of summarized MAC addresses.