Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 323)

any port before determining that a loop exists. This value is the pdu-rx-limit . You must also set the
interval between sending PDUs by using the hello-interval command The combination of pdu-rx-limit
and hello-interval timer determines the time it takes for ELD to detect and break a Layer 2 loop.
At the interface level, you must enable ELD on each port you want it to run on and set the port priority.
You should also specify a VLAN on which ELD is enabled
Enter the pdu-rx-limit command to set the limit to a different number on each Brocade VCS Fabric
cluster so that only one Brocade VCS Fabric cluster disables a port. We recommend setting this value
in the increment of two to prevent race conditions which might disable ports on two Brocade VCS Fabric
clusters that are incrementally only one apart.
Enter the hello-interval command to set the interval between PDUs. This interval must be set to the
same value on all Brocade VCS Fabric clusters for which ELD is configured, otherwise the results of
edge-loop detection become unpredictable.
Optionally, enter the shutdown-time command to configure ports to be re-enabled after a specified
period of time (range 10 minutes to 24 hours). A typical use for this feature is in environments in which
reconfiguration is common, such as in a typical lab environment. Typical use is to allow the default
value of zero, which does not allow ports to be re-enabled automatically.
NOTE
Any change to shutdown-time only takes effect for the ports that are disabled by ELD after the
configuration change. Any ports that were already disabled by ELD before the shutdown-time change
continues to follow the old shutdown-time value. These ports start to follow the new shutdown time
after the currently running timer expires and ELD still detects the loop and shuts down the port again.
For each interface on which ELD runs, enter the edge-loop detection command to enable ELD. You
must also enter the edge-loop-detection port-priority command to specify the ELD-port priority.
Setting global ELD parameters for a Brocade VCS Fabric cluster
Perform this procedure on every Brocade VCS Fabric cluster where you configure ELD.
The values in this example configure the Brocade VCS Fabric cluster to detect and break loops on
receipt of 5 PDUs. Because the PDU interval is set to 2000 ms (2 seconds), any loop breaks after 10
seconds. The selected port will remain disabled for 24 hours, after which it is automatically re-enabled.
1. Log in to any switch in a Brocade VCS Fabric cluster.
2. In global configuration mode, enter the protocol edge-loop-detection command to enter edge-loop
detection configuration mode.
switch(config)# protocol edge-loop-detection
3. Enter the pdu-rx-limit number command to set the number of PDUs that will be received before
breaking the Layer 2 loop.
The number operand must be a value in the range1 through 5. The default value is 1.
switch(config-eld)# edge-loop-detection pdu-rx-limit 5
4. Enter the hello-interval number command to set the interval between PDUs.
The number operand has a unit of 1 millisecond (ms). It must be in the range from 100 ms to
5000ms . The default value is 1000 ms.
switch(config-eld)# hello-interval 2000
5. Enter the edge-loop-detection shutdown-time number command to set the number of minutes
after which the shutdown port is re-enabled.
The number value must be in the range 10 through 1440 (10 minutes through 24 hours). The default
value is 0, indicating that the port is not automatically re-enabled.
switch(config-eld)# edge-loop-detection shutdown-time 1440
Setting global ELD parameters for a Brocade VCS Fabric cluster
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