Brocade FastIron Ethernet Switch Administration Guide - Manual (Page 80)

The line "Link Error Dampening" displays "Enabled" if port flap dampening is enabled on the port or
"Disabled" if the feature is disabled on the port. The feature is enabled on the ports in the two
examples above. Also, the characters "ERR-DISABLED" is displayed for the "GbpsEthernet" line if the
port is disabled because of link errors.
Syntax: show interface ethernet port-number
In addition to the show commands above, the output of the show interface brief command for
FastIron X Series indicates if a port is down due to link errors.
device# show interface brief e17
Port Link State Dupl Speed Trunk Tag Priori MAC Name
17 ERR-DIS
None None None 15 Yes level0 0000.0000.010e
The ERR-DIS entry under the "Link" column indicates the port is down due to link errors.
NOTE
If a port name is longer than five characters, the port name is truncated in the output of the show
interface brief command.
Syslog messages for port flap dampening
The following Syslog messages are generated for port flap dampening.
• If the threshold for the number of times that a port link toggles from "up" to "down" then "down" to
"up" has been exceeded, the following Syslog message is displayed.
0d00h02m10s:I:ERR_DISABLE: Link flaps on port ethernet 16 exceeded threshold; port
in err-disable state
• If the wait time (port is down) expires and the port is brought up the following Syslog message is
displayed.
0d00h02m41s:I:ERR_DISABLE: Interface ethernet 16, err-disable recovery timeout
Port loop detection
This feature allows the Brocade device to disable a port that is on the receiving end of a loop by
sending test packets. You can configure the time period during which test packets are sent.
Types of loop detection
There are two types of loop detection; Strict Mode and Loose Mode. In Strict Mode, a port is disabled
only if a packet is looped back to that same port. Strict Mode overcomes specific hardware issues
where packets are echoed back to the input port. In Strict Mode, loop detection must be configured on
the physical port.
In Loose Mode, loop detection is configured on the VLAN of the receiving port. Loose Mode disables
the receiving port if packets originate from any port or VLAN on the same device. The VLAN of the
receiving port must be configured for loop detection in order to disable the port.
Syslog messages for port flap dampening
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