HP StorageWorks Fabric OS 6.1.x administrator guide (5697-0234, November 2009)

350 Administering Extended Fabrics
Example: Consider the 8/24 SAN Switch, which has 24 ports and total buffers of 676
The maximum remaining number of buffer credits after each port is reserved is:
676 – (24 * 8) = 484 buffers
Where:
24 = the number of ports in a port group retrieved from Table 77.
8 = the number of reserved buffers
676 = a static number retrieved from Table 77.
If you allocate the entire 484 + 8 reserved buffers = 492 buffers to a single port; that port can support
486km @ 2G, which is the reserved buffer for distance.
How many 50km ports you can configure?
If you have a distance of 50km at 8 Gbps then 484 / (206 – 8) = 2 ports.
If you have a distance of 50km at 1 Gbps then 484 / (31 – 8) = 21 ports.
NOTE: The 10 Gbps FC10-6 blade has two port groups of three ports each. For extended ISLs, all buffers
available to a group are used to support one port at up to 120 km.
Displaying the remaining buffers in a port group
Issue the portbuffershow command to display all of the long distance buffer information for all the port
groups of the switch. Use the following syntax:
portbuffershow [[slotnumber/]portnumber]
1. Connect to the switch and log in as admin.
slotnumber For bladed systems only, specifies the slot number of the port group
to display, followed by a slash (/).
portnumber Specifies the number of a port associated with the port group,
relative to its slot for bladed systems. Use switchShow for a list of
valid ports.