Cisco 7925G Administration Guide - Page 33

Chapter 2 Overview of the VoIP Wireless Network Understanding WLAN Standards and Technologies • Cisco Catalyst 3750 Series Integrated Wireless LAN Controllers-Adds wireless LAN controller functions to the stackable Cisco Catalyst 3750G Series Switches to improve operating efficiency, security, mobility, and ease of use for WLAN administrators. • Wireless Control System (WCS)-Provides a powerful systems management. System administrators can design, control, and monitor enterprise WLANs from a centralized location. • Cisco 2700 Series Wireless Location Appliance-802.11 based location tracking solution for asset tracking, IT management, and location based security. An open API is included. • Cisco Wireless LAN Client Adapters-Available in CardBus, PCMCIA and PCI form factors, Cisco Aironet Wireless LAN Client Adapters connect desktop and mobile computing devices to the WLAN in 802.11b-compliant or 802.11a-compliant network. For more information about Cisco Unified Wireless Networks, refer to http://www.cisco.com/en/US/products/hw/wireless/index.html Understanding WLAN Standards and Technologies This section describes the following concepts: • 802.11 Standards for WLAN Communications, page 2-3 • Radio Frequency Ranges, page 2-4 • 802.11 Data Rates, Tx Power, Ranges, and Decibel Tolerances, page 2-4 • Wireless Modulation Technologies, page 2-5 • AP, Channel, and Domain Relationships, page 2-6 • WLANs and Roaming, page 2-7 802.11 Standards for WLAN Communications Wireless LANs must follow the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards that define the protocols that govern all Ethernet-based wireless traffic. The Cisco Unified Wireless IP Phone 7925G supports the following standards: • 802.11b-Specifies the radio frequency (RF) of 2.4 GHz for both transmitting and receiving data. Commonly called the Wi-Fi standard. • 802.11g-Uses the same unlicensed 2.4 GHz band as 802.11b, but extends the data rates to provide greater performance by using Orthogonal Frequency Division Multiplexing (OFDM) technology. OFDM is a physical-layer encoding technology for transmitting signals by using RF. • 802.11a-Uses the 5 GHz band that provides more channels and improved data rates by using OFDM technology. Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) supports this standard. • 802.11d-Enables APs to communicate available radio channels and acceptable power levels. The Cisco Unified Wireless IP Phone 7925G will always give precedence to 802.11d to determine which channels and powers to use. If the information is unavailable, then the phone will fallback to the locally configured regulatory domain. OL-15984-01 Cisco Unified Wireless IP Phone 7925G Administration Guide for Cisco Unified Communications Manager 7.0(1) 2-3