Chapter 6 Managing Ports 187
Longer distances can be spanned at full bandwidth on ports by extending credits to
G_Ports, F_Ports, and E_Ports. Each port can donate 15 credits to a pool from which
a recipient port can borrow. The recipient port also loses a credit in the process. For
example, you can configure a recipient port to borrow 15 credits from one donor
port for a total of 30 credits (15+15=30). This will support communication over the
following approximate distances:
■50 Km at 1-Gbit/sec (30÷0.6)
■25 Km at 2-Gbit/sec (30÷1.2)
■12 Km at 4-Gbit/sec (30÷2.4)
■6 Km at 8-Gbit/sec (30÷4.8)
Note – You can utilize unused donor ports with the Extended Credit Wizard only
when pointing to a switch running firmware that supports this feature.
To extend credits, open the Wizards menu and select Extended Credit Wizard. The
Extended Credit Wizard leads you through the following process to extend credits
based on transmission distance requirements:
1. Extended Distance — explains the concepts and principles of extending port
credits. Click the Next button.
2. Extended Distance Requirements — specify speed and distance requirements for
each port then click the Next button.
3. Designate Donor Ports — select available ports and click >> to move the port into
the Selected Donor Port column (FIGURE6-8). Match the number of ports needed
with the number of designated donor ports. Click the Next button.