requirements. Most vendors list the power consumption of their equipment on their web pages. Simply find out what kind of power the devices require (AC/DC, voltage, and amperage), and the connectors needed, and add up the requirements for each rack. Talk with whoever is responsible for the environment where your racks are located, and make sure that they can sup- port the equipment you're putting into your racks. Just because you can fit 40 1-RU servers in a rack doesn't mean you can power them! The default AC power installed in a rack in a colloca- tion facility is often two 20-amp AC power strips. If your 1-RU servers each draw 2 amps, and have two power supplies, you can only install 10 in each rack. If you want to add more, you'll need to order extra power. Don't forget cooling requirements, either. Along with power specifications, vendors will list the British Thermal Unit (BTU) values for their devices. The person responsi- ble for the environment where the equipment will be installed will also need to know this information. Even though you can physically install two 6509s in a rack, the required air conditioning systems may not be in place to keep them cool. To find power and heat values for 6500 switches, search Cisco's site for "6500 power and heat numbers." Because the power draw and heat output vary depending on the modules installed, you must figure out this information for each installation. The numbers for the 6509 I specified earlier are shown in Figure 33-7. A similar spread- sheet should be compiled for every device you will be installing. Device Module Part number Watts Core-16509E Slot 1 48 Port 10/100/1000 WS-X6748-GE-TX 367.50 1,255.01 Slot 2 48 Port 10/100/1000 WS-X6748-GE-TX 367.50 1,255.01 Slot 3 48 Port 10/100/1000 WS-X6748-GE-TX 367.50 1,255.01 Slot 4 48 Port 10/100/1000 WS-X6748-GE-TX 367.50 1,255.01 Slot 5 Sup-720 WS-SUP720-3B 350.80 1,204.81 Slot 6 Sup-720 WS-SUP720-3B 350.80 1,204.81 Slot 7 WS-SVC-FWM-1-K9 214.73 733.29 Slot 8 Slot 9 48 Port 10/100/1000 WS-X6748-GE-TX 367.50 1,255.01