For ultrafast packet switching, low-bit-rate packets are optically multiplexed to high-bit-rate packets and assigned an optical label at the edge node. These high-bit-rate packets are routed through the network by all-optical label swapping. At the destination, the label is removed and the high-bit-rate packet is optically demultiplexed to low-bit-rate packets. See Rau et al., pp. 100-118.