Features that differentiate between HBA products include:
Multiple ports supporting redundant and/or aggregated data paths.
Most HBAs sold today are 4Gb/s but there are still 2Gb/s
HBAs on the market.
Most HBA vendors now have 8Gb/s FC support.
Use of removable transceivers
SFPs provide more flexibility than fixed interfaces but can cost
To another port on the same HBA or to a different HBA in the same
host. HBA vendors typically supply multipathing drivers for their
HBAs, but these drivers offer varying levels of functionality. Criteria
include failover time, recovery capability, and support for load-
levelling (manual path selection or dynamic path selection).
Support for protocols other than SCSI-FCP, including IP and VI.
Support for multiple Classes of Service
Many HBAs support only Class 3, but others support Classes 2
Support is required for interoperability with some native FC tape
libraries and drives.
The ability to boot a host from a remote SAN-attached disk.