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Chapter 5: Fibre Channel Hub Operation and Management
Changing Interval and Threshold Settings
An interval is the measure of time—24 microseconds—that is examined for errors.
The default interval value is set at 10 (240 microseconds), but you can change it to any
value from 1 to 15. The (error) threshold setting determines when a port is automatically
bypassed for excessive errors. The default is 7, but you can set it to any value from 1 to 15.
Interval and threshold work together. For example, if the interval is 10 and the threshold
is 7, ten frame times are examined for errors. If six or fewer errors are found, no corrective
action is taken and transmission continues. If another interval is examined and the total
number of errors reaches 7, the port is automatically bypassed. The bypassed port is
reinserted if no errors occur during the next interval.
Note:
The threshold value must be equal to or less than the interval value.
This section explains how to display and change interval and threshold settings using the
command-line interface and the Internet browser interface, in separate subsections.
•
“Changing Interval and Threshold Settings: Command-Line Interface” on page 72
•
“Changing Interval and Threshold Settings: Internet Browser Interface” on page 73
Caution:
Changing these values from their factory defaults changes the behavior of the
arbitrated loop, which can have disastrous consequences. Do not change these values
unless you have good reason to do so. Setting threshold and interval values both to 1
disables automatic port bypass.
Changing Interval and Threshold Settings: Command-Line Interface
To change the interval using the command-line interface, a user with administrator
privilege enters
Server>>change hub interval
intervalvalue
where
intervalvalue
is a number from 1 to 15 (default 10).
To change the error threshold, a user with administrator privilege enters
Server>>change hub threshold
thresholdvalue
where
thresholdvalue
is a number from 1 to 15 (default 7).
