Most long-haul ocean routing runs through at least one transshipment: the box is discharged at a hub port, waits for the connecting service, and loads onto the second vessel for the onward leg, which adds handling and transit time the desk plans around. A transshipment is a planned step set when the booking is made, distinct from a container rollover, where the carrier bumps a booked box onto a later sailing after the fact. Each transfer is a point where the container can miss its connection, so the desk tracks the hub move and the connecting vessel rather than treating the journey as a single sailing. A direct service, by contrast, carries the cargo from load port to discharge port on one vessel with no intermediate transfer.
Glossary
Transshipment
The transfer of cargo from one vessel to another at an intermediate hub port, so a shipment with no direct service reaches its destination on a connecting ship after being moved at the hub.