3Com 4007 Getting Started Manual

Also see for 3CGBIC97 - Switch 4007 70km Gigabit Enet Gbic: Installation guide Installation guide

Contents

3Com 4007 Getting Started Manual Manual pdf 69 page image

Power Management 69See the documentation that is supplied with eachmodule to determine your module powerrequirements. Take into account any modules thatyou plan to install, as well as those that are alreadyinstalled.Power Supply ModesThe Switch 4007 runs in either of two power supplymodes:n Fault-Tolerant Moden Non-Fault Tolerant ModeFor optimal power redundancy in either power mode,run the Switch 4007 with two power supplies.Fault-Tolerant ModeA user-selectable mode in which power that isequivalent to one power supply is held in reserve. Thisreserve power is not available to installed modulesuntil a power supply fails, or until you switch thepower mode from power fault-tolerant mode topower non-fault-tolerant mode.While the chassis is running in fault-tolerant mode:n All installed power supplies are functioning andcontributing power to the chassis and modules.No single power supply is a dedicated standbypower supply.Rather, a factory-defined power limit (which isbased on the number of installed power supplies)ensures that power that is equivalent to at leastone power supply is available to replace powerthat is lost when a power supply fails.n The amount of power that installed modules in achassis require must not be greater than thenumber of installed power supplies, minus one(n-1). When you reserve power that is equivalentto one power supply in power fault-tolerant mode,the failure of a single power supply has no impacton installed modules that are already powered on.If a power supply fails while the switch is running inpower fault-tolerant mode:n EMEs respond by automatically disabling powerfault-tolerant mode.n Power formerly reserved (unavailable to installedmodules) is made available by power class and slotlocation to power-enabled Switch 4007 modulesto prevent them from powering off (as an attemptto bring power consumption under thenow-reduced power budget).n All modules that had power before the powersupply failure continue to receive power withoutinterruption.n Upon power supply recovery, the EMEautomatically reenables power fault-tolerantmode.