When you use NIC teaming, consider that the server MAC address is originally learned on Port 0/1 of theswitch (shown in the following) and Port 0/5 is the failover port. When the NIC fails, the systemautomatically sends an ARP request for the gateway or host NIC to resolve the ARP and refresh the egressinterface. When the ARP is resolved, the same MAC address is learned on the same port where the ARP isresolved (in the previous example, this location is Port 0/5 of the switch). To ensure that the MAC addressis disassociated with one port and reassociated with another port in the ARP table, the no mac-address-table station-move refresh-arp command should not be configured on the DellNetworking switch at the time that NIC teaming is being configured on the server.NOTE: If you have configured the no mac-address-table station-move refresh-arpcommand, traffic continues to be forwarded to the failed NIC until the ARP entry on the switchtimes out.Figure 66. Configuring the mac-address-table station-move refresh-arp CommandConfigure Redundant PairsNetworks 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 linksbetween switches because they create switching loops (as shown in the following illustration). Theredundant pairs feature allows you to create redundant links in networks that do not use STP byconfiguring 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 backupinterface remains in a Down state until the primary fails, at which point it transitions to Up state. If theprimary interface fails, and later comes up, it becomes the backup interface for the redundant pair. DellNetworking OS supports Gigabit, 10 Gigabit, and 40-Gigabit interfaces as backup interfaces.Layer 2 517
