FW 07.00.00/HAFM SW 08.06.00 McDATA Sphereon 4500 Fabric Switch Installation and Service Manual (620-000159-320, April 2005)

2
Installation Tasks
2-111
Installation Tasks
NOTE: The default congestion threshold is calculated by the
switch’s firmware.
5. Click the Unresolved Congestion check box to add a check mark
and enable the parameter. When this parameter is enabled,
unresolved congestion events are recorded in the event log, and
SNMP trap messages are generated and transmitted (if SNMP is
configured).
An unresolved congestion event occurs for a low-BB_Credit ISL
when the switch’s firmware rerouting algorithm cannot route
data flow to an alternate path (because doing so would exceed the
alternate path’s low BB_Credit threshold).
6. Click the Backpressure check box to add a check mark and enable
the parameter. When this parameter is enabled, backpressure
events are recorded in the event log, and SNMP trap messages are
generated and transmitted (if SNMP is configured).
A backpressure event occurs when the percent time an ISL has
low BB_Credit exceeds the low BB_Credit threshold.
7. The low BB_Credit threshold is the percent time an ISL is allowed
to not transmit data because BB_Credit is unavailable. When the
threshold is exceeded, data is rerouted to another ISL. In addition,
traffic cannot be rerouted to another low- threshold ISL. Use one
of the following to set the low BB_Credit threshold:
— Click the Default Threshold check box. A check mark appears in
the box and a calculated default value appears (1% to 99%) in
the adjacent field. If the default value is enabled, a value
cannot be entered in the field.
— Ensure the Default Threshold check box is blank. At the adjacent
field, type a percentage value from 1% to 99%.
NOTE: The default low BB_Credit threshold is calculated by the
switch’s firmware.
8. Click Activate to enable the changes and close the dialog box.