One embodiment of the present invention provides a switch. The switch includes a switch group module, a persistent storage module, and an allocation module. The switch group module maintains a membership in a switch group. The switch group includes a plurality of switches and operates as a single switch. The persistent storage module stores configuration information associated with the switch group in a data structure in a local persistent storage. The allocation module determines that a second switch is in a default mode and obtains a switch identifier from the persistent storage based on a switch media access control (MAC) address of the second switch. The allocation module then constructs a control message, which is destined for the second switch and includes the switch identifier and a switch group identifier of the switch group.