When you hot-plug a network interface into a vRouter , the router assigns the first virtualized PCI slot that is available to the interface. For example, if the first, second, and third PCI slots are in use, the new interface is hot-plugged into the fourth slot. In this case, the name of the new interface is dp0p256p1. However, if the interface that is associated with the second slot is deleted later, when you hot-plug a new interface, the new interface is plugged into the second slot (dp0p192p1).