How does AIX recognize the link?

To AIX, the exchange data link is simply another piece of hardware that needs to be defined as a device, just like a printer or a disk drive. The procedure depends on the type of link:

ACL link
The Multiprotocol Communications Adapter is defined and configured automatically, and you need only check that its status is Available.
SMDI, SMSI, or VMS link
The pSeries hardware configuration needs to be changed to include the link.