Methods for switching traffic include a physical machine running source and destination virtual machines (VMs). The source VM issues a data unit addressed to the destination VM. The physical machine has a physical network interface in communication with the VMs. The physical network interface transmits a sub-packet, which includes a partial portion of the data unit, over a network while a majority portion of the data unit remains at the physical machine. A network switch on the network receives the sub-packet transmitted by the physical network interface. The network switch performs one or more OSI Layer 2 through Layer 7 switching functions on the sub-packet and returns that sub-packet to the physical network interface. The physical network interface identifies the data unit stored in the memory in response to the sub-packet returned from the network switch and forwards the identified data unit to the destination VM.