Extended Credit Wizard Dialog Box; Extended Credits-Minimum Cable Lengths - HP StorageWorks 8/20q User Manual

from one donor port for a total of 30 credits (15+15=30). This supports communication over the following
approximate distances:
• 50 km at 1 Gb/s (30÷0.6)
• 25 km at 2 Gb/s (30÷1.2)
• 12 km at 4 Gb/s (30÷2.4)
• 6 km at 8 Gb/s (30÷4.8)
Extending credits requires a minimum cable length that is dependent on transmission speed, but is
independent of the number of credits borrowed. Extending credits using short cables can cause excessive
port resets. Table 37
Table 37 Extended Credits—Minimum Cable Lengths
Transmission Speed
1 Gb/s
2 Gb/s
4 Gb/s
8 Gb/s
NOTE: Supported distances are also dependent on the selection of SFP (shortwave or longwave) and the
type of fiber cable. See the Fibre Channel distance rules in the HP StorageWorks SAN Design Reference
Guide available at the HP website http://www.hp.com/go/sandesignguide.
The Extended Credit wizard leads you through the following process to extend credits based on
transmission distance requirements. To extend credits:
1. Select a switch from the fabric tree.
2. Select Wizards > Extended Credit Wizard to open the Extended Credit Wizard dialog box
• Extended Distance—Explains the concepts and principles of extending port credits. Click Next.
• Extended Distance Requirements—Specify speed and distance requirements for each port. Click
Next.
• Designate Donor Ports—Select available ports, and click >> to move the port into the Selected
Donor Port column. Match the number of ports needed with the number of designated donor ports.
Click Next.
• Verify requested changes—Review the extended distance requests and the selected donor ports.
Click Finish to apply the changes and redistribute the credits.
Figure 82

Extended Credit Wizard dialog box

140 Managing Ports
describes the minimum cable lengths for a port with extended credits.
Minimum Cable Length
3 km
1.5 km
0.75 km
0.37 km
(Figure 82).