44 Brocade ICX 6650 Administration Guide
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Basic port parameter configuration
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loops because STP cannot prevent loops across different VLANs. In these instances, the ports are
not blocked and loop detection is able to send out probe packets in one VLAN and receive packets
in another VLAN. In this way, loop detection running in Loose Mode disables both ingress and egress
ports.
Enabling loop detection
Use the loop-detection command to enable loop detection on a physical port (Strict Mode) or a
VLAN (Loose Mode). Loop detection is disabled by default. The following example shows a Strict
Mode configuration.
Brocade(config)# interface ethernet 1/1/1
Brocade(config-if-e10000-1/1/1)# loop-detection
The following example shows a Loose Mode configuration.
Brocade(config)# vlan20
Brocade(config-vlan-20)# loop-detection
By default, the port will send test packets every one second, or the number of seconds specified by
the loop-detection-interval command. Refer to “Configuring a global loop detection interval” on
page4 4.
Syntax: [no] loop-detection
Use the [no] form of the command to disable loop detection.
Configuring a global loop detection interval
The loop detection interval specifies how often a test packet is sent on a port. When loop detection
is enabled, the loop detection time unit is 0.1 second, with a defa ult of 10 (o ne second ). The ra nge
is from 1 (one tenth of a second) to 100 (10 seconds). You can use the show loop-detection status
command to view the loo p detection interval .
To configure the global loop detection interval, enter a command similar to the following.
Brocade(config)# loop-detection-interval 50
This command sets the loop-detection interval to 5 seconds (50 x 0.1).
To revert to the default global loop detection interval of 10, enter one of the following.
Brocade(config)# loop-detection-interval 10
OR
Brocade(config)# no loop-detection-interval 50
Syntax: [no] loop-detection-interval <number>
where <number> is a value from 1 to 100. The system multiplies your entry by 0.1 to calculate the
interval at which test packets will be sent.
Configuring the device to automatically re-enable ports
To configure the Brocade ICX 6650 device to automatically re-enable ports that were disabled
because of a loop detection, enter the errdisable recovery cause loop-detection command.