Cisco WS-C4003 Software Guide - Page 350

Power Management Chapter 26 Administering the Switch In systems with redundant power supplies, both power supplies must be of the same wattage. The Catalyst 4000 family switches allow you to mix AC-input and DC-input power supplies in the same chassis. For detailed information on supported power supply configurations for each chassis, refer to the Catalyst 4000 Family Installation Guide. Catalyst 4000 family modules have different power requirements; thus, some switch configurations require more power than 1+1 redundancy mode (a single power supply) can provide. In those configurations, redundancy requires three power supplies. Redundant and nonredundant power configurations are discussed in the following sections. Power Redundancy The Catalyst 4006 switch contains holding bays for up to three power supplies. You need two primary power supplies to operate a fully loaded Catalyst 4006 chassis. You can set the power redundancy to two primary plus one redundant power supply (2+1 redundancy mode) or to one primary plus one redundant power supply (1+1 redundancy mode). The 1+1 redundancy mode does not support a fully loaded chassis. If your switch has only two power supplies and is in 2+1 redundancy mode (the default mode), there is no redundancy. You can create redundancy with only two power supplies by setting the power redundancy to operate in 1+1 redundancy mode (one primary plus one redundant power supply). However, 1+1 redundancy will not support all configurations. The 1+1 redundancy mode is designed and optimized for a specific hardware configuration: a Catalyst 4006 chassis with a WS-X4013 supervisor engine and four WS-X4148-RJ or WS-X4148-RJ21 modules. Although other configurations are possible, we do not recommend that you use them without careful consideration of the power usage in the system. For example, other similar and possible configurations can consist of four modules, where each module consumes 65W or less (for a total of 265W), or more generally, where the total module power usage does not exceed the absolute maximum module usage of 265W. The supervisor engine uses 110W and the fan box uses 25W, for a system total of 400W (modules + supervisor + fan). The 1+1 redundancy mode cannot support a fully loaded chassis, regardless of the module configuration, and, therefore, one slot of the chassis must be empty. Any attempt to use five modules guarantees an oversubscription of available power. If you opt to use the 1+1 redundancy mode, the type and number of modules supported are limited by the power available from a single power supply. To determine the power consumption for each module in your chassis, see the "Power Consumption of Modules" section on page 26-14. To choose a 1+1 redundancy configuration, you must change the system configuration from the default 2+1redundancy mode to 1+1 redundancy mode by using the set power budget command. The set power budget 1 command sets the power budget to accommodate a 1+1 redundancy mode. In the 1+1 redundancy mode, the nonredundant power available to the system is the power of a single power supply. The second power supply installed in your switch provides full redundancy. Limitations of the 1+1 Redundancy Mode If you attempt to configure the system to operate in 1+1 redundancy mode, and you have more modules installed in the chassis than a single power supply can handle, the system will prevent you from enabling the1+1 redundancy mode. If you are already operating in 1+1 redundancy mode with a valid module configuration and you attempt to insert additional modules that require more power than the single power supply provides, the system immediately places the newly inserted module into reset mode and issues these error messages: Module 26-12 Software Configuration Guide-Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4 78-12647-02