Chapter 12Cisco’s Wireless

Technologies

WLAN Frequencies

•900MHz and 2.4GHz bands are referred to as the Industrial, Scientific, and Medical (ISM) bands.•5.7GHz band is known as the Unlicensed National Information Infrastructure (UNII) band.

CommitteePurposeIEEE 802.11a54Mbps, 5GHz standard

IEEE 802.11bEnhancements to 802.11 to support 5.5 and 11Mbps

IEEE 802.11cBridge operation procedures; included in the IEEE 802.1D standard

IEEE 802.11dInternational roaming extensions

IEEE 802.11eQuality of service

IEEE 802.11FInter-Access Point Protocol

IEEE 802.11g54Mbps, 2.4GHz standard (backward compatible with 802.11b)

IEEE 802.11hDynamic Frequency Selection (DFS) and Transmit Power Control (TPC) at 5Ghz

IEEE 802.11iEnhanced security

IEEE 802.11jExtensions for Japan and U.S. public safety

IEEE 802.11kRadio resource measurement enhancements

The 802.11 Standards

CommitteePurposeIEEE 802.11mMaintenance of the standard; odds and ends

IEEE 802.11nHigher throughput improvements using MIMO (multiple input, multiple output antennas)

IEEE 802.11pWireless Access for the Vehicular Environment (WAVE)

IEEE 802.11rFast roaming

IEEE 802.11sExtended Service Set (ESS) Mesh Networking

IEEE 802.11TWireless Performance Prediction (WPP)

IEEE 802.11uInternetworking with non-802 networks (cellular, for example)

IEEE 802.11vWireless network management

IEEE 802.11wProtected management frames

IEEE 802.11y3650–3700 operation in the U.S

• 2.4GHz (802.11b): (11, 5.5, 2, and 1Mbps), Direct Sequence Spread Spectrum (DSSS)

• 2.4GHz (802.11g): 54Mbps, Orthogonal Frequency Division Multiplexing (OFDM)• 5GHz (802.11a ): (54, 48, 36, 24, 18, 12, and 6Mbps)• 5GHz (802.11h): Dynamic Frequency Selection (DFS), Transmit Power Control

(TPC) & additional 11 channels• 2.4GHz/5GHz (802.11n): Using MIMO

5GHz affecting with interference is less than that of 2.4GHz, reasons for interference are:

1. Cordless phones2. Metal cabinets3. Microwaves ovens4. Antenna type & direction5. Bluetooth devices

CSMA/CA

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is also called aRequest To Send, Clear To Send (RTS/CTS)

Classification ofWireless Networks

Connecting APs (Cisco’s Unified Wireless Solution)• If the APs weren’t root, they could only connect to a root device as a repeater. Nonroot devices include clients, bridges, repeater access points, and work group bridges.• Cisco WLAN controllers (come with gigabit interfaces).• Controllers decide the packet’s destiny based on the Lightweight Access Point Protocol (LWAPP) information that’s encapsulated on it.• Split-MAC Architecture is the splitting the processing of the 802.11 protocol between two devices, the AP and a centralized Cisco WLAN controller.• The controller is managed either through the controller web interface, from the controller itself, or from Cisco’s Wireless Control System (WCS)

APs Functions•The frame exchange handshake between a client and AP when transferring a frame over the air•Transmitting beacon frames•Buffering and transmitting frames for clients in power save operations•Responding to probe request frames from clients•Forwarding notification of received probe requests to the controller•Providing real-time signal quality information to the controller with every received frame•Monitoring each of the radio channels for noise, interference, and other WLANs•Monitoring for the presence of other APs•Encryption and decryption except in the case of VPN/IPSec clients

Controller Functions•802.11 authentication•802.11 association and reassociation (mobility)•802.11 frame translation and bridging

Cisco Wireless Controller can do its job with more facilities using the GUI Wirelss Control System (WCS)

MESH, LWAPP, and AWPP

•Root Access Points (RAPs)•Mesh Access Points (MAPs): 32 MAPs over a 5GHz•Adaptive Wireless Path Protocol (AWPP) runs on all APs

Wireless Security•Open Access•Service Set Identifier (SSID): Open authentication and shared-key authentication•Wired Equivalency Protocol (WEP): 40 or 128 bits•Media Access Control (MAC) authentication•Wi-Fi Protected Access (WPA) & (WPA2) Pre-Shared Key (PSK) (using password or passphrase)

Cisco Unified Wireless Network Security•Secure Connectivity for WLANs: using strong dynamic encryption keys (WPA) & (WPA2)•Trust and Identity for WLANs: using IEEE 802.1X:EAP, RADIUS, & AAA server•Threat Defense for WLANs: using intrusion Prevention System (IPS), WLAN NAC, and advanced location services

Configuring WLANRouter(config)#int dot11radio 0/3/0Router(config-if)#ip address 10.1.8.1 255.255.255.0Router(config-if)#description Admin WLANRouter(config-if)#ssid ADMINRouter(config-if-ssid)#guest-modeRouter(config-if-ssid)#authentication openRouter(config-if-ssid)#infrastructure-ssidRouter(config-if-ssid)#no shut