When your stack is operational, one switch is the primary switch, responsible for running network protocols and managing the stack.
To provide recovery in case of a break in the stack connections, you can configure redundancy by designating a backup switch to take over as primary if the primary switch fails. When you perform the initial software configuration of the stack, the “easy setup” configuration option automatically configures redundancy, with slot 1 as the primary and slot 2 as the backup. You can also configure additional switches as “primary-capable,” meaning they can become a stack primary in case the initial backup switch fails.
When assigning the primary and backup roles in mixed stacks, consider the feature scalability and the speed of each switch model. The easy setup configuration process selects primary and backup switches based on capability and speed. The following list shows the capabilities based on the ability to cross stack with other switch families. The most capable switches are shown at the top of each list:
For example, in a stack that combines 5720 series switches with 5520 series switches, a 5720 series switch might provide more memory and more features than the 5520 series switches in the stack. Consider these differences when selecting a primary node, selecting a backup node, and configuring failover operation.
Important
5720 series switches can be stacked with themselves using either Native V400 stacking (SummitStack-V400) or Native V400-alternative-configuration (SummitStack-V400-alternative-configration), or with the 5520 series switches using Native V200 stacking (SummitStack-V200). Assign the primary and backup roles to switches from the same series. For example, if the primary node is a 5720 series switch, the backup node must also be a 5720 series switch. The 5520 series switches must only be used as standby nodes when they are in a mixed stack with 5720 Series switches. Similarly, if the primary node is an 5520 series switch, the backup node must also be an 5520 series switch.When easy setup compares two switches that have the same capability, the lower slot number takes precedence.
Follow the same ranking hierarchy when you plan the physical placement of the switches in the stack.