A first processor assigns switches and/or switch ports to a virtual stack according to configuration information and stores the virtual topography of the virtual stack in a mapping table. The mapping table correlates switches, switch ports, computer processors, and virtual stacks. The first processor receives a data unit from a first switch that includes a source address and a destination address. The destination address identifies a switch and switch port. The first processor compares the destination address to the mapping table to determine a second computer processor and sends the data unit to the second computer processor, the second computer processor corresponding to a switch and/or switch port identified in the destination address of the data unit.