Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.112.1P1 - Page 512
Con Redundant Pairs
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NOTE: If you have configured the no mac-address-table station-move refresh-arp command, traffic continues to be forwarded to the failed NIC until the ARP entry on the switch times out. Figure 70. Configuring the mac-address-table station-move refresh-arp Command Configure Redundant Pairs Networks that employ switches that do not support the spanning tree protocol (STP) - for example, networks with digital subscriber line access multiplexers (DSLAM) - cannot have redundant links between switches because they create switching loops (as shown in the following illustration). The redundant pairs feature allows you to create redundant links in networks that do not use STP by configuring 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 Networking OS supports Gigabit, 10 Gigabit, and 40-Gigabit interfaces as backup interfaces. Apply all other configurations to each interface in the redundant pair such that their configurations are identical, so that transition to the backup interface in the event of a failure is transparent to rest of the network. 512 Layer 2
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