HP StorageWorks 2405 - Disk System User Manual page 29

Multimode
A type of fiber optic cable that allows more than one mode (rays of light) to be
guided.
Arbitrated Loop (FC-AL)
A Fibre Channel topology that provides a low-cost solution to attach multiple
communicating ports in a loop without hubs and switches.
Arbitrated Loop Physical Address (AL_PA)
A unique one-byte valid value assigned during Loop Initialization to each
NL_Port or FL_Port on a Loop.
Product Description 29