HP Surestore Disk Array 12h and FC60 - Manual (Page 116)

116 Topologies for HP-UX
Because each HP Fibre Channel-AL Hub has ten ports, either two host adapters and eight
controller modules or four host adapters and six controller modules can attach to each HP
Fibre Channel-AL Hub. If any hardware component (controller module, host Fibre Channel
I/O adapter, HP Fibre Channel-AL Hub, or fibre optic cable) fails in one Fibre Channel-AL,
the I/O communication between hosts and disk arrays can continue through the other Fibre
Channel-AL.
Supported cable lengths for each segment of the Fibre Channel-AL include 2 m, 16 m, 50 m,
100 m, and 500 m. The maximum combined cable lengths for all segments, that is, the total
length of the Fibre Channel-AL should not exceed 5000 m because performance can
degrade due to propagation delay. Because of this it is recommended that the total cable
length of the Fibre Channel-AL be as short as possible. Fibre optic cables in lengths of 2 m,
16 m, 50 m, and 100 m cables can be ordered from Hewlett-Packard (see chapter 8 for part
numbers). Fibre optic cables longer than 100 m must be custom-fabricated for each
implementation.