Brocade Communications Systems 6650 manual Enabling loop detection, Syntax no loop-detection

2 Basic port parameter configuration

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-detectioncommand 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-intervalcommand. Refer to “Configuring a global loop detection interval” on page 44.

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 default of 10 (one second). The range is from 1 (one tenth of a second) to 100 (10 seconds). You can use the show loop-detection status command to view the loop 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-detectioncommand.

44	Brocade ICX 6650 Administration Guide
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