Concept Guide

following illustration). The redundant pairs feature allows you to create redundant links in networks that do not use STP by conguring
backup interfaces for the interfaces on either side of the primary link.
NOTE: For more information about STP, refer to Spanning Tree Protocol (STP).
Assign a backup interface to an interface using the switchport backup command. The backup interface remains in a Down state until
the primary fails, at which point it transitions to Up state. If the primary interface fails, and later comes up, it becomes the backup interface
for the redundant pair. Dell EMC Networking OS supports Gigabit, 10 Gigabit, and 40-Gigabit interfaces as backup interfaces.
Apply all other congurations to each interface in the redundant pair such that their congurations are identical, so that transition to the
backup interface in the event of a failure is transparent to rest of the network.
Figure 63. Conguring Redundant Layer 2 Pairs without Spanning Tree
You congure a redundant pair by assigning a backup interface to a primary interface with the switchport backup interface
command. Initially, the primary interface is active and transmits trac and the backup interface remains down. If the primary fails for any
reason, the backup transitions to an active Up state. If the primary interface fails and later comes back up, it remains as the backup
interface for the redundant pair.
Following primary/backup interfaces are also supported:
• primary interface is a physical interface, the backup interface can be a physical interface
• primary interface is a physical interface, the backup interface can be a static or dynamic LAG
• primary interface is a static or dynamic LAG, the backup interface can be a physical interface
• primary interface is a static or dynamic LAG, the backup interface can be a static or dynamic LAG
In a redundant pair, any combination of physical and port-channel interfaces is supported as the two interfaces in a redundant pair. For
example, you can congure a static (without LACP) or dynamic (with LACP) port-channel interface as either the primary or backup link in a
redundant pair with a physical interface.
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Layer 2