A Fiber Channel switch is provided for a relative addressing scheme for domain values to avoid losing portions of a Fiber Channel identifier. At a Fiber Channel switch, data is stored that assigns a relative domain field value to a run-time domain. The relative domain field value used for a Fiber Channel identifier is determined for devices connected to the switch based on the run-time domain of the devices and the virtual storage area network in which the devices are active. A Fiber Channel identifier is stored in a memory of the switch that comprises the relative domain field value determined for the device together with area and port values for the device. The relative domain value is either a reserved domain field value for an existing virtual storage area network or any of the regular domain field values for a new virtual storage area network.