Extreme SLX-OS Layer 2 Switching Configuration Guide, 20.2.1a

Enter global configuration mode.

device# configure terminal

Enter the protocol loop-detection command to enable loop detection, enter Protocol Loop Detect configuration mode, and configure a variety of global options.

device(config)# protocol loop-detection

(Optional) Enter the hello-interval command to change the hello interval from the default.

device(config-loop-detect)# hello-interval 2000

(Optional) Enter the shutdown-time command to change from the default the interval after which an interface that is shut down by loop detection (LD) protocol is automatically reenabled.

device(config-loop-detect)# shutdown-tiome 20

(Optional) Enter the raslog-duration command to change from default the interval between RASLog messages that are sent when a port is disabled by the loop detection (LD) protocol.

device(config-loop-detect)# raslog-duration 20

Enable LD at the interface level.

In global configuration mode, specify an interface (either an Ethernet interface or a port-channel interface).
```
device(config)# interface ethernet 0/6
```
In interface subtype configuration mode, enter the loop-detection command.
```
device(conf-if-eth-0/6)# loop-detection
```

Enable LD at the VLAN level.

In global configuration mode, create a VLAN.
```
device(config)# vlan 5
```
In VLAN configuration mode, enter the loop-detection command.
```
device(config-vlan-5)# loop-detection
```

Associate the VLAN with an interface.

In global configuration mode, specify an interface (either an Ethernet interface or a port-channel interface).
```
device(config)# interface ethernet 0/6
```
In interface subtype configuration mode, enter the loop-detection vlan command and specify a VLAN. (The VLAN must already be created.)
```
device(conf-if-eth-0/6)# loop-detection vlan 5
```

(Optional) Disable the shutting down of an interface (Ethernet or port-channel) as a result of the loop detection (LD) protocol.

In global configuration mode, specify an interface (either an Ethernet interface or a port-channel interface).
```
device(config)# interface ethernet 0/6
```
In interface subtype configuration mode, enter the loop-detection shutdown-disable command.
```
device(conf-if-eth-0/6)# loop-detection shutdown-disable
```

(Optional) Disable the shutting down of an interface (Ethernet or port-channel) as a result of the loop detection (LD) protocol.

In global configuration mode, specify an interface (either an Ethernet interface or a port-channel interface).
```
device(config)# interface ethernet 0/6
```
In interface subtype configuration mode, enter the loop-detection shutdown-disable command.
```
device(conf-if-eth-0/6)# loop-detection shutdown-disable
```

Confirm the LD configuration, using the show loop-detection command with a variety of options.

To display LD information at the system level, enter the show loop-detection command as in the following example.

device# show loop-detection
Strict Mode:
------------------------

Number of loop-detection instances enabled: 1

Interface: eth 0/6
        Enabled on VLANs: 100
        Shutdown Disable:   No
        Interface status: UP
        Auto enable in: Never

Packet Statistics:
vlan            sent            rcvd        disable-count
100             100             0           0

Loose Mode:
------------------------

Number of LD instances:   2
Disabled Ports:                   2/7

Packet Statistics:
vlan            sent            rcvd        disable-count
100             100             0           0

To display ports disabled by LD, enter the show loop-detection disabled-ports command as in the following example.

device# show loop-detection disabled-ports
Ports disabled by loop detection
-------------------------------------------
port       age(min)       disable cause
0/6        5              Disabled by Self

To display global LD configuration values, enter the show loop-detection globals command.

device# show loop-detection globals
Loop Detection:                 Disabled
Shutdown-time (minutes):        0
Hello-time (msec):              1000
Raslog-duration (minutes):      10

Use the clear loop-detection command in privileged EXEC mode with a variety of options to reenable ports that were disabled by LD and clear the LD statistics.

To enable LD-disabled ports and clear LD statistics on all interfaces, enter the clear loop-detection command.
```
device# clear loop-detection
```
To enable LD-disabled ports and clear LD statistics on an Ethernet interface, enter the clear loop-detection interface ethernet command.
```
device# clear loop-detection interface ethernet 0/6
```
To enable LD-disabled ports and clear LD statistics on a port-channel interface, enter the clear loop-detection interface port-channel command.
```
device# clear loop-detection interface port-channel 20
```
To enable LD-disabled ports and clear LD statistics on a VLAN, enter the clear loop-detection interface vlan command.
```
device# clear loop-detection interface vlan 10
```

Configuring LD protocol