A method for routing data on a fat-tree network using network switches includes assigning a customized MAC address to each host device in the network. The customized MAC address has a set of bits for each level in the fat-tree network, each set of bits corresponding to a division of the network in which the host device is located. Each switch applies a MAC subnet mask to a destination MAC address of each received packet and performs at least one hashing function on the masked destination MAC address to determine a forwarding port for the packet.