Chapter 1. IBM Flex System FC3171 8 Gb SAN Switch - QLogic
Chapter 1. IBM Flex System FC3171 8 Gb SAN Switch - QLogic
Chapter 1. IBM Flex System FC3171 8 Gb SAN Switch - QLogic
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I/O Stream Guard<br />
The I/O Stream Guard feature suppresses the Registered State Change Notification<br />
(RSCN) messages on a port basis. I/O Stream Guard should be enabled only on<br />
ports connected to initiator devices. To configure the I/O Stream Guard option<br />
using the Port Properties dialog, open the Port menu, and select Port Properties.<br />
Select the option that corresponds to one of the following options:<br />
• Enable—suppresses the reception of RSCN messages from other ports for which<br />
I/O Stream Guard is enabled.<br />
• Disable—allows free transmission and reception of RSCN messages.<br />
• Auto—suppresses the reception of RSCN messages when the port is connected<br />
to an initiator device with a <strong>QLogic</strong> HBA. For older <strong>QLogic</strong> adapters, such as the<br />
QLA2200, Device Scan must be enabled. The default is Auto. See ”Device scan”<br />
on page 5-94.<br />
Device scan<br />
The Device Scan feature queries the connected device during login for FC-4<br />
descriptor information. Disable this parameter only if the scan creates a conflict<br />
with the connected device.<br />
Auto performance tuning and AL fairness<br />
The Auto Perf Tuning and AL Fairness settings are configured using the Advanced<br />
Port Properties dialog shown in Figure 39. The Auto Perf Tuning option enables the<br />
switch to dynamically control the MFS_Enable, VI_Enable and LCF_Enable features<br />
based on the operational state of the port.<br />
The AL Fairness option controls how frequently the switch can arbitrate for access.<br />
Once a port has arbitrated and won access to the loop, it does not try again until all<br />
others have had an opportunity to arbitrate for the loop. This setting applies only to<br />
ports running in loop (FL) mode.<br />
To open the Advanced Port Properties dialog, select one or more ports, open the<br />
Port menu, and select Advanced Port Properties.<br />
Figure 39. Advanced Port Properties dialog<br />
94 <strong>IBM</strong> <strong>Flex</strong> <strong>System</strong> <strong>FC3171</strong> 8 <strong>Gb</strong> <strong>SAN</strong> <strong>Switch</strong> QuickTools User’s Guide