Configuring a Stack

Before configuring a new stack, do the following:
  • Ensure that every switch, or node, in the stack is running on the same partition (primary or secondary). To find this information for any node, issue the command show switch and look for the Image Booted field in the output.
  • Ensure that every switch in the stack is running the same version and patch level of ExtremeXOS. To find this information for any node, issue the command show switch and look for the Primary Ver or Secondary Ver field in the output.
  • If necessary, enable switch license levels or configure license level restrictions for the nodes in the stack.
  • We recommend that you save the configuration for each switch that will participate in the stack, so that you can reinstate the configuration after the switch is no longer needed in the stack.


New switches are primary-capable by default.

Because stacks can consist of switches of different series and different models, ExtremeXOS does not restrict configuration settings based on the capabilities of any particular node in the stack. Therefore, you are responsible for ensuring that your configuration settings are appropriate for all switches in the stack.

The following switch families come from the factory with stacking-support enabled with stack ports set to a default configuration. The following table describes the default configuration for each switch:

Table 1. Universal Switch Default Stack Port Configuration
Switch Stack port default configuration
ExtremeSwitching 5320 SummitStack V400
ExtremeSwitching 5420 SummitStack V40
ExtremeSwitching 5520 SummitStack V160
ExtremeSwitching 5720 SummitStack V40


ExtremeSwitching 5720 and ExtremeSwitching 5520 switches contain different types of EXOS images. The ExtremeSwitching 5720 requires an onie_x86_64 image type, and the ExtremeSwitching 5520 requires a summit_arm image type. Before building a mixed stack of these two switch families, all switches must have the same release level image loaded onto all nodes.

Once a mixed stack of ExtremeSwitching 5720 and ExtremeSwitching 5520 switch families has been built, a software upgrade is required. Download and install the onie-summitarm-bundle.lst image, which combines the onie_x86_64 image and the summit_arm image into one bundle.

Alternatively, you can use the following two step upgrade process:

  1. Download the onie_x86_64 image (and optionally install) onto the Primary node in the stack.
  2. Download the summit_arm image (and optionally install) onto the Primary node in the stack.
Follow these steps to configure a new stack. Some of the steps include references where you can find additional information.
  1. Physically connect the switches (stack nodes) using their stacking ports or alternate stacking ports.

    Instructions for physically setting up the stack are provided in the hardware installation guide for your switch.

  2. Power on the switches.
  3. On each switch, issue the command enable stacking-support.
    This command configures the switch so that it is capable of being added to a stack. It is not the same as enable stacking, which you will use later to build the stack.
  4. Ensure that all of the cabled stacking ports are enabled for stacking:
    1. On each node, issue the command show ports x,y, where x and y are the port numbers.
      In the output, port state = E means a port is enabled.
    2. For any ports that are not enabled, issue the command enable ports x,y, where x and y are the port numbers.
    3. If you enabled ports on any switches, reboot those switches.
      Save the configuration files.
  5. Configure all switches in the stack that will use the SummitStack-V, SummitStack-V160, SummitStack-V320, SummitStack-V400, or MPLS features.


    If the stack will use MPLS, only the 5520 switch can act as primary and backup.
    1. Configure switches that will use alternate stacking ports as described in Use Ethernet Ports for Stacking (SummitStack-V Feature).
    2. Reboot the switches whose configurations you changed.
  6. Log in, using the console port, to the switch that will be the primary.
  7. Issue the command show stacking stack-ports to verify that the stacking ports are properly connected.
    All of the ports should show a state of Operational.
    In the following example, two of the ports are not in an Operational state, which means they are not connected properly.
    * switch1 # show stacking stack-ports
    Stack Topology is a Ring
    Slot Port Select Node MAC Address  Port State  Flags Speed
    ---- ---- ------ ----------------- ----------- ----- -----
    *-   1    27     00:04:96:9c:e4:39 Operational C-      10G
    *-   2    28     00:04:96:9c:e4:39 Operational CB      10G
     -   1    27     00:04:96:9b:c1:34 Operational CB      10G
     -   2    28     00:04:96:9b:c1:34 Operational C-      10G
     -   1    15     00:04:96:9e:5c:76 Link Down   C-      10G
     -   2    16     00:04:96:9e:5c:76 No-Neighbor C-      10G
     -   1    15     00:04:96:9c:53:b6 Operational C-      10G
     -   2    16     00:04:96:9c:53:b6 Operational C-      10G
    * - Indicates this node
    Flags:  (C) Control path is active, (B) Port is Blocked
    When a port displays a state other than Operational, use the following tips to troubleshoot:
    • If the state displays as Link Down, check the port's physical connections.
    • Verify that the port is using the same stacking technology, for example SummitStack-V160, as the rest of the ports in the stack.
  8. Verify that all nodes in the stack have stacking disabled.
    Note that, even though you enabled stacking-support in step 3, it is necessary that stacking be disabled before the stack is actually built.
    1. Issue the command show stacking configuration.
      For example:
      * switch1 # show stacking configuration
      Stack MAC in use: <none>
      Node               Slot         Alternate          Alternate
      MAC Address        Cfg Cur Prio Mgmt IP / Mask     Gateway         Flags     Lic
      ------------------ --- --- ---- ------------------ --------------- --------- ---
      *00:04:96:9c:e4:39 1   -   Auto <none>             <none>          -c-----Nn --
       00:04:96:9b:c1:34 1   -   Auto <none>             <none>          -c-----Nn --
       00:04:96:9e:5c:76 1   -   Auto <none>             <none>          -c-----Nn --
       00:04:96:9c:53:b6 1   -   Auto <none>             <none>          -c-----Nn --
      * - Indicates this node
      Flags:  (C) master-Capable in use, (c) master-capable is configured,
              (E) Stacking is currently Enabled, (e) Stacking is configured Enabled,
              (M) Stack MAC in use, (m) Stack MACs configured and in use are the same,
              (i) Stack MACs configured and in use are not the same or unknown,
              (N) Enhanced protocol is in use, (n) Enhanced protocol is configured,
              (-) Not in use or not configured
      License level restrictions: (C) Core, (A) Advanced edge, or (E) Edge in use,
              (c) Core, (a) Advanced edge, or (e) Edge configured,
              (-) Not in use or not configured
    2. If a node is enabled for stacking (shown by a capital letter E in the Flags column), issue the command disable stacking node-address mac_address for that node.
      Then reboot the switch.
  9. From the node that will be the primary, issue the command enable stacking.
    The following prompt displays:
    X440G2-24t-10G4.4 # enable stacking
    You have not yet configured all required stacking parameters.
    Would you like to perform an easy setup for stacking operation? (y/N) 
  10. Enter y to proceed with Easy Setup (strongly recommended), or enter n to configure the stack manually.
    • When you enter y for Easy Setup, you are prompted to confirm your choice:
      Executing "configure stacking easy-setup" command...
      For every node in the 4-node stack, this command will:
      - enable stacking
      - configure a stack MAC address
      - choose and configure a slot number (this node will be assigned to slot 1)
      - configure redundancy to minimal (slot 1 will be the master node)
      - configure the stacking protocol to enhanced
      Upon completion, the stack will automatically be rebooted into the new configuration.
      Warning: If stacking is already configured, this command will alter that configuration.
      Do you wish to proceed? (y/N)	

      Enter y again to confirm. All of the switches reboot automatically and form a stack in which one switch is the primary, one is the backup, and the rest are standby nodes. Easy Setup configures all other required stacking parameters for every switch in the stack.

    • If you forgo Easy Setup by entering n in response to the prompt (not recommended), you will need to configure the stack manually. Instead of continuing with step 11, follow the steps in Manually Configuring a Stack.
  11. Verify the configuration, following the instructions in Verifying the Configuration.
  12. Save the ExtremeXOS configuration to every active node in the stack.
    On the primary node, issue the command save configuration config_name, where config_name is a descriptive name for this configuration.
    The stacking-specific configuration parameters are saved in a file called config_name.cfg to the NVRAM of each node.
The stack is ready to use.