Dell Force10 S4820T S4820T Configuration Guide - Page 598

www.dell.com | support.dell.com Configuring Redundant Pairs e c s Configuring Redundant Pairs is supported on platforms: Z S4820T Networks that employ switches that do not support Spanning Tree (STP) - for example, networks with Digital Subscriber Line Access Mutiplexers (DSLAM) - cannot have redundant links between switches because they create switching loops (Figure 28-6). The Redundant Pairs feature enables 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 details on STP, see Chapter 48, "Spanning Tree Protocol (STP)," on page 945. Assign a backup interface to an interface using the command switchport backup. The backup interface remains in 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. FTOS supports Gigabit, 10-Gigabit, and 40-Gigabit interfaces as backup interfaces. You must 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. Figure 28-6. 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 598 | Layer 2 fnC0067mp