A network switch device receives a communication packet having a source MAC address s and a destination MAC address d at a switch port p. Then, the network switch device determines whether a valid routing table entry (s, p) exists, there by indicating that the source MAC address s is reachable via a switch port p. The network switch device further determines for the destination MAC address d whether there is at least one switch port q for which a valid routing table entry (d, q) exists, there by indicating that d is reachable via a switch port q. When the routing table entries (s, p) and (d, q) exist, the network switch device routes the communication packet to the switch port q.