Dell Force10 E1200i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 556

www.dell.com | support.dell.com Configuring Redundant Pairs Configuring Redundant Pairs is supported: c e s • On physical interfaces on platforms c e s • On static and dynamic port-channel interfaces on platforms The Redundant Pairs feature allows you to provide redundancy for Layer 2 links without using Spanning Tree (STP). You create redundant links by configuring pairs of Layer 2 (physical or port-channel) interfaces so that only one interface is up and carries user traffic at any time. Interfaces on either side of a link provide backup for the primary link. Redundant pairs are useful in service-provider and enterprise networks in which you do not run STP on switches-for example, networks with Digital Subscriber Line Access Mutiplexers (DSLAM)-to avoid creating switching loops (refer to Figure 28-7). Note: For details on STP, refer to the Spanning Tree Protocol chapter. Figure 28-7. Configuring Redundant Layer 2 Pairs without Spanning Tree Redundant links create a switching loop. Without STP broadcast storms occurs. Use backup interfaces to create redundant links in networks without STP FTOS(conf-if-gi-3/41)#switchport FTOS(conf-if-gi-3/41)#switchport backup gi 3/42 FTOS(conf-if-gi-3/41)#no shutdown R3 3/41 FTOS(conf-if-gi-4/31)#switchport FTOS(conf-if-gi-4/31)#no shutdown R4 4/31 FTOS(conf-if-gi-3/42)#switchport FTOS(conf-if-gi-3/42)#no shutdown Backup Link 3/42 4/32 FTOS(conf-if-gi-4/32)#switchport FTOS(conf-if-gi-4/32)#no shutdown fnC0067mp You configure 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 traffic 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. 556 | Layer 2