Using The Extended Credits Wizard; Designate Donor Ports - Qlogic SANbox 5602 User Manual

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5.3

Using the Extended Credits Wizard

Each port is supported by a data-buffer with a 16-credit capacity; that is, 16
maximum sized frames. For fiber optic cables, this enables full bandwidth service
over a distance of 26 kilometers at 1-Gbps (0.6 credits per Km), 13 kilometers at
2-Gbps (1.2 credits per Km), or 6 kilometers at 4-Gbps (2.4 credits per Km).
Longer distances can be spanned at full bandwidth by borrowing credits from
designated donor ports thus pooling the buffer capacities. This is called credit
extension. Each donor port contributes 15 credits to the pool from which the
recipient ports can draw. The recipient port also loses one credit in the process.
For example, one donor port contributes 15 credits to the pool from which a
recipient draws for a total of 30 credits (15+15). This provides approximately 50
Km at 1-Gbps (30÷0.6), 25 Km at 2-Gbps (30÷1.2), or 13 Km at 4-Gbps (30÷2.4).
Only 1-Gbps/2-Gbps/4-Gbps ports can donate or borrow credits. To extend
credits, open the Wizards menu and select Ext 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 shown in
of ports needed with the number of designated donor ports. Click the Next
button.
59097-00 A
Figure 5-3. Designate Donor Ports
5 – Managing Ports
Using the Extended Credits Wizard
Figure 5-3. Match the number
5-15