Setting Up Resilient Links 4-19Setting Up Resilient LinksYou can configure a Switch to provide resilient linksto another device so that network disruption is mini-mized if a link fails. A resilient link pair consists of amain link and a standby link. You define a resilientlink pair by specifying the main port and standbyport at one end of the pair.Figure 4-13 Resilient link pairUnder normal network operating conditions, themain link carries your data. The Receive Idle signalof a fiber link or the Test Pulse on an Ethernettwisted pair link is continually monitored by theSwitch. If a signal loss is detected, the Switch imme-diately enables the standby port so that it carries thedata. In addition, the main port is disabled.If a main link has a higher bandwidth than itsstandby link, traffic is automatically switched back tothe main link provided no loss of link is detected fortwo minutes. Otherwise, you need to manuallyswitch traffic back to the main link.When setting up resilient links, you should note thefollowing:n Up to 13 resilient link pairs can be configured ona 24-port Switch 1000, and up to seven pairs canbe configured on a 12-port Switch 1000.n Resilient links cannot be set up if Spanning Tree(STP) is enabled on the Switch.n Resilient Links can only be set up on fiber ortwisted pair links. The main and standby links inthe same pair, however, can use any combina-tion of these media.n A resilient link pair can only be set up if:n The ports belong to the same VLAN.n The ports have an identical security setting.n Neither of the ports forms part of anotherresilient link pair.n If the main port is VLT (Virtual LAN Trunk) port,the standby port must also be a VLT port.n A resilient link pair must be defined at only oneend of the connection.n You cannot disable any port that is part of a resil-ient link pair.
