Introduction to switch stack management

See the ArubaOS-Switch Installation and Getting Started Guide for information on supported stacking topologies.


This feature is not the stacking feature implemented on other Networking switches, implemented with front-panel networking cables, which does not have the high bandwidth and redundancy features of 2920 stacking.

The stacking feature lets you connect up to four switches and have them act as a single high-bandwidth switch for both data and management.

One switch in the stack is designated as “Commander” and one switch is elected to be the “Standby.” The other switches are designated “Member.” The Commander is responsible for the overall management of the stack. The Standby provides redundancy for the stack and takes over stack management operations should the Commander fail, or if a Commander failover is forced by an administrator. The Members are not part of the overall stack management, however, they must manage their local subsystems and ports to operate correctly as part of the stack. The Commander and Standby are also responsible for their own local subsystems and ports.

Switch Stack Management (stacking) enables you to use a single IP address and standard network cabling to manage a group of up to 16 total switches in the same IP subnet (broadcast domain). Using stacking for the switch enables you to:
  • Simplify management of small workgroups or wiring closets while scaling your network to handle increased bandwidth demand.

  • Add switches to your network without having to first perform IP addressing tasks.

  • Reduce the number of IP addresses needed in your network.

  • Reduce downtime with high availability in the event of a failure.


When the switch is configured in a stack, the amount of configurable MSTIs is limited to four. If stacking is enabled and a fifth MSTI is created, an error will occur.

However, when the switch is configured as a standalone, a maximum of 16 MSTIs are supported.


In the default configuration, stacking is enabled on switches. However, if a switch is powered on and it does not have a Stacking Module installed, stacking is disabled. If a Stacking Module is subsequently installed in the switch, stacking must be enabled from the switch CLI (in the config context) by entering the following command:

switch(config)#: stacking enable