possible directions it can turn left it can go straight to the adjacent switch it may be sent internally u2014 when it has reached its final destination or it can turn right and be directed to the switch which is diagonally across from it 2 a packet arriving on the straight input has been sent by an adjacent switch inside the same tile consequently it can only be directed outside 3 a packet arriving on the internal input can only be directed outside in this case the sender unit has selected the switch based on the direction in which to send the packet out 4 a packet arriving on the across input has been sent by the switch positioned diagonally across from the receiving switch within the same tile that packet may only be sent outside with continued reference to fig2 there is shown the internal architecture of a switch in our four switch tile architecture all switches are identical with four input and output ports and three internal components an enqueuing module eq internal memory voq and a dequeuing module sf when more than one packet destined to the same output port arrive at different input ports of a switch in the same time.