new ccna study guide

new ccna study guide.Figure 8-1 Use of Standard Cordless PhonesIn 2005, the FCC changed the channel classification and licensing fees for 1920 MHz.1930 MHz (or 1.9 GHz bandwidth). This band is considered to be the unlicensed personal communications services ( UPCS, UnlicensedPersonalCommunicationsServices) band. This change by the FCC allows DECT equipment to be used in the United States with little or no modification. The improved DECT device is called DECT6.0o This enables a distinction to be made between DECT devices used abroad and other cordless devices operating in the 900MHz, 2.4GHz and 5.8GHz bands.8.2.2 Bluetooth Bluetooth (Bluetooth) is a personal local area network technology named after King Harald "Bluetooth" Gormson of Denmark. The purpose of Bluetooth technology was to unify the telecommunications and computer industries. Today, Bluetooth technology is incorporated into devices such as mobile phones, PDAs, portable computers, desktops, printers, headphones, cameras, and video game consoles. The low power consumption of Bluetooth technology makes it the best choice for mobile, battery-powered devices. The Bluetooth Special Interest Group (SIG) was founded in 1998 and officially adopted the name "Bluetooth". In 1999, Bluetooth 1.0 and 1.0b were released, although they were barely usable. Then the more powerful Bluetooth 1 was released. Finally, based on Bluetooth 1.1, the IEEE approved the 802.15.1 specification, making it compliant with Bluetooth technology. In 2003, Bluetooth L2 was adopted, with its faster connection and discovery of devices, and its use of adaptiveFrequencyHoppingSpreadSpectrum technology. In 2004, the Bluetooth SIG adopted Bluetooth 2.0+ Enhanced Data Rate (EDR, EnhancedDataRate), which supports a maximum rate of up to 2 Mbit/s. Subsequently the IEEE released 802.15.1.2005, which is a specification related to Bluetooth 1.2. After the 802.15.1-2005 standard, the IEEE severed its relationship with the Bluetooth SIG because the SIG wanted to work on other standards. One of the main features of the Bluetooth 2.1 standard is an improved quick-pairingprocess in which two devices can be paired together to start the quick-pairing process. There is also a new technology called "sniffsubrating "w that extends battery life by up to 5 times. Bluetooth 2.1+EDR is backwards compatible with Bluetooth 1.1. Bluetooth technology can interfere with 802.11LAN, as it operates in the 2.4GHz band. However, because it is specifically designed for100 Chapter 8 Other Wireless Technologies35 feet or so in close proximity, has very low transmission power, and uses frequency hopping spread spectrum technology, Bluetooth generally does not interfere with 802.11LANOBluetooth is considered a piconet, which allows eight devices (one master and seven slaves) to pair, as shown in Figure 8.2. Although the graph has some extremes, it shows the number of devices paired to a single laptop or desktop. You can download photos you've taken while listening to music on your headset, sync your phone contacts and PDA calendar with Outlook, and use your mouse to print a new white paper on Cisco.com, playing video games while doing all of this. You can imagine how cluttered these connections would be without Bluetooth.8.2.3 ZigBeeAlthough many people have never heard of ZigBee, ZigBee is a well-designed and very useful technology. ZigBee technology was developed by the ZigBee Alliance. It consists of small, low-power digital radios based on the IEEE 802.15.4 standard for Wireless Personal Area Networks (WPAN, WirelessPersonal-AreaNetworks), for example through8.2 Basic Topics 101wireless headset connected to a cell phone by a short-range radio. If one looks at the ZigBee Alliance home page at http://www.zigbee.org,