The input/output adapter (IOA) has a preset address (also known as the burned-in address or the manufacturer-assigned address). You have the option of setting the address for each IOA to an address of your choice.
If you are using SNA, it is preferred that you use an address of your choice. For example, if you use the burned-in address of the adapter, configure this address into every device that communicates with the adapter. If, at a later point in time you replace the adapter, go back to each device and reconfigure them with the burned-in address of the new adapter. You cannot assign the burned-in address of the old adapter to the new adapter.
However, you can avoid the excess reconfiguration work by associating a locally administered address with the adapter. Because the other devices will already have the locally administered address configured, you will not need to reconfigure them when you replace the IOA. Instead, you can associate the existing locally administered address with the new adapter.