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Example: Configuring Automated Fibre Channel Interface Load Rebalancing

Automated Fibre Channel (FC) interface (NP_Port) load rebalancing configures the switch to rebalance the session loads on the native FC interfaces automatically on a load-rebalancing trigger event. (Alternatively, you can rebalance the link load on the FC interfaces on demand so that you control when the link load is rebalanced.) Rebalancing the FC link load is a disruptive action that causes some or all of the current sessions to log out, then log in again to be placed on the active FC links in a balanced manner.

This example shows you how to configure and verify automated FC link load rebalancing on an FCoE-FC gateway local FC fabric.


This example uses the following hardware and software components:

  • Juniper Networks QFX3500 Switch

  • Junos OS Release 12.3 or later for the QFX Series


When a load rebalancing trigger occurs, the switch automatically rebalances the link loads by redistributing the sessions across the active NP_Port links.

There are three possible load-rebalancing triggers:

  1. When you enable automated load rebalancing, the switch checks the load balance on the existing NP_Port links. If the links are already balanced, the switch does not rebalance the link load. If the links are not balanced, the switch rebalances the link loads using the configured load-balancing algorithm.

  2. When a new NP_Port link comes up on a local FCoE-FC gateway fabric, the switch rebalances the link load using the configured load-balancing algorithm if automated load balancing is enabled.

  3. When the port speed is changed (unless the port speed change does not change the actual port speed, for example, changing the port speed from auto to 8 Gbps).

Automated load rebalancing logs out sessions in accordance with the configured load-balancing algorithm. Disabling automated load rebalancing is not disruptive because the link load is already balanced.

Use automated load rebalancing if you want link loads to be rebalanced automatically instead of at times of your choosing. Keep in mind that load rebalancing is a disruptive event (sessions are logged out).


This example configures automated load rebalancing on a local FC fabric on an FCoE-FC gateway. This example does not show you how to configure the load-balancing algorithm or any other load-balancing characteristics. The load-balancing configuration for this example is:

  • FC fabric name—fc_fabric_100

  • FC fabric ID—100

  • FC fabric type—Proxy

  • FC fabric interfaces—fc-0/0/0, fc-0/0/1, fc-0/0/42, fc-0/0/43, vlan.100, vlan.20

  • Load-balancing algorithm—Simple

  • No fabric WWN verify—Configured

  • Traceoptions—Configured to log in file fc_fabric_100_proxy.log


To configure automated load balancing on a local FC fabric, perform this task:

CLI Quick Configuration

To quickly configure automated load balancing, copy the following commands, paste them in a text file, remove line breaks, change variables and details to match your network configuration, and then copy and paste the commands into the CLI at the [edit] hierarchy level:


Step-by-Step Procedure

  • Configure automated load balancing on FC fabric fc_fabric_100:


Display the results of the configuration:


Verifying That Automated Load Rebalancing Is Enabled


Verify that automated load rebalancing is configured on local FC fabric fc_fabric_100.


Verify the results of the automated load-rebalancing configuration using the operational mode command show fibre-channel proxy fabric-state fabric fc_fabric_100:


The show fibre-channel proxy fabric-state fabric fc_fabric_100 operational command displays information about the specified local FC fabric. The output shows that the Auto load rebalance enabled field value is Yes, which indicates that automated load rebalancing is enabled on fabric fc_fabric_100.