In today's logistical environment where small orders and frequent deliveries are expected, cross docking offers an important advantage. Cross docking is a logistical activity that consolidates shipments from inbound trailers to outbound trailers in buildings known as cross docks. At each cross dock, each inbound trailer typically arrives from a different origin, carrying shipments meant for different destinations. These shipments are then quickly unloaded from the inbound trailers, sorted, consolidated, and reloaded onto outbound trailers bound for different destinations. Typically, all shipment handling is completed within a day, with little or no holding of stock in the cross dock.