Wireless Protocols You Just Have to Know About! Todd Lammle (FCC RF Licensed) Certified Wireless Administrator (CWA) instructor, Sybex author www.wirelesstechnologygroup.org www.globalnettraining.com www.routersim.com
About Todd Lammle
President, GlobalNet Training, inc
CEO, RouterSim, LLC
To understand the term “WLAN”
To understand the current IEEE wireless standards
To understand the future IEEE wireless standards
To gather information that will allow you to make informed decisions
Why do we care?
Can I just use it till I need glasses? Wireless Is Addicting Once You Use It You Can’t Live without It
What’s a typical “LAN”?
What’s a typical WLAN? It’s a “hub” without wires
Wireless LANS (WLANs) use “Cells”
Channel Overlap to cover distance
Audio AM Broadcast Short-Wave Radio FM Broadcast Television Infrared Wireless LAN Cellular (840MHz) NPCS (1.9GHz) Extremely Low Very Low Low Medium High Very High Ultra High Super High Infrared Visible Light Ultra- violet X-Rays ISM Unlicensed Frequency Bands 902–928 MHz 26 MHz 5 GHz (IEEE 802.11) HyperLAN HyperLAN2 2.4–2.4835 GHz 83.5 MHz (IEEE 802.11)
What is the Wireless LAN Hardware?
Devices In a Wireless Network
Access Point: An AP operates within a specific frequency spectrum and uses an 802.11 standard specified modulation technique.
It also informs the wireless clients of its availability and authenticates and associates wireless clients to the wireless network.
An AP also coordinates the wireless clients' use of wired resources.
Wireless Access Points
Serves as a connection point for wireless users to connect to the wired LAN
Contention-based, half-duplex device
Not necessary in Ad Hoc networks
Physical/Data Link Layer device
Has Layer-2 filtering capabilities
1, 2, 5.5, or 11 Mbps connectivity depending on standard implemented
Think of this device as a 10BaseT hub
Access Point Example
Network interface card (NIC)/client adapter: A PC or workstation uses a wireless NIC to connect to the wireless network.
The NIC scans the available frequency spectrum for connectivity and associates it to an access point or another wireless client.
The NIC is coupled to the PC/workstation operating system using a software driver.
Bridge: Wireless bridges are used to connect multiple LANs (both wired and wireless) at the Media Access Control (MAC) layer level.
Used in building-to-building wireless connections, wireless bridges can cover longer distances than AP’s (IEEE 802.11 standard specifies 1 mile as the maximum coverage range for an AP).
Wireless Bridged Network
Wireless Workgroup Bridge
Users are connected via wired Ethernet to the bridge, which is then connected via wireless Ethernet to the Access Point, which then connects to the wired backbone
Used to connect a small group of users (8 or less) to the wireless network
Users are a "collective client" on the wireless network
Antenna: An antenna radiates the modulated signal through the air so that wireless clients can receive it.
Characteristics of an antenna are defined by propagation pattern (directional versus omnidirectional), gain, transmit power, and so on.
Antennas are needed on both the AP/bridge and the clients.
Campus Antenna Example
IEEE 802.11 WLAN Physical MAC layer IEEE 802.11 LLC layer IEEE 802.2 SNAP Infrared Light Direct Sequence Spread Spectrum Frequency Hopping Spread Spectrum Packet Layer Convergence Protocol (PLCP)
802.11a Standard 5 GHz – OFDM* 54 Mbps 802.11b Standard 2.4 GHz – DSSS 11Mbps 1999 2000 2001 2002 Network Radio Speed 2003 * *Orthogonal Frequency Division Multiplexing ( OFDM ) 802.11b uses complementary Code Keying (CCK) as its modulation scheme Quadrature Phase Shift Keying
IEEE 802.11 who?
Original recipe 802.11: Ratified June, 1997, 1 or 2Mbps at 2.4Ghz.
The big event- 802.11b (Wi-Fi): 1, 2, 5.5 and 11Mbps, 2.4 GHz, ratified in 1999. Didn’t take off until late 2000. Backward compatible to 802.11
First in line, last to produce products- 802.11a: Up to 54Mbps, 5 GHz, ratified in 1999. Not compatible with 802.11 and 802.11b
802.11a is 5Ghz
Range of 5Ghz is about 30% less then 2.4Ghz
Overall investment of infrastructure is much higher with 5Ghz (for now)
Typical 2.4 Ghz range is 150 feet
Typical 5Ghz range is 50 feet
Not compatible with 802.11a and 802.11b
The data rates specified by IEEE 802.11a are 6, 9, 12, 18, 24, 36, 48, and 54 Mbps, with support for 6, 12, and 24 Mbps
802.11c: Management Group
802.11d: Committee trying to add 802.11 into other countries that can’t use 2.4Ghz. Only Spain now…
802.11e: Quality of Service (QoS), multimedia and security as well as error correction. Uses TDMA like Cisco’s up and coming 802.11a products.
802.11f: Inter-Access Point Protocol (IAPP), Mobile IP
802.11g: 54Mbps in 2.4Ghz range
802.11h: Group trying to take 802.11a into Europe with 802.11e specs.
802.11i: Wireless Authentication and Security
802.11j: So new, there is still no members! Group will focus on 802.11a and HiperLAN2 coexistence
11 and 54Mbs WLAN’s 802.11g
Provides higher date rates at 2.4 Ghz
Similar to 802.11b
Backward compatible to
Wireless Ethernet Compatibility Alliance (WECA): Drafted the Wi-Fi System Interoperability testing document
Wireless Fidelity (Wi-Fi): Agilent Technologies in San Jose performs the independent WLAN products testing. After testing, the WECA board awards the Wi-Fi seal
Wireless Ethernet Compatibility Alliance (WECA)
Mission statement—WECA’s mission is to certify interoperability of Wi-Fi ™ (IEEE 802.11b) products and to promote Wi-Fi as the global wireless LAN standard across all market segments
Goal —Provide users with a comfort level for interoperability
Presently over 100 different product certified and growing
Supports ONLY 802.11b 11MB DS products
Other Wireless Technologies
Bluetooth is a personal-area network (PAN) specified by the Bluetooth Special Interest Group for providing low-power and short-range wireless connectivity using frequency-hopping spread spectrum in the 2.4-GHz frequency environment.
In 1988, The HomeRF SWAP Group published the Shared Wireless Access Protocol (SWAP) standard for wireless digital communication between PCs and consumer electronic devices within the home.
SWAP supports voice and data over a common wireless interface at 1 and 2-Mbps data rates using frequency-hopping and spread-spectrum techniques in the 2.4-GHz band.
Was known as “HomeRF Light”
Less then $2 per module for manufacturer
Runs off of cheap AA batteries
Up to 115kbps
From 10 meters to 75 meters
All-in-one product (power, tx, rx, ant.)
HiperLAN is a European Telecommunications Standards Institute (ETSI) standard ratified in 1996. HiperLAN/1 standard operates in the 5-GHz radio band up to 24 Mbps.
ETSI has recently approved HiperLAN/2, which operates in the 5-GHz band at up to 54 Mbps using a connection-oriented protocol for sharing access among end-user devices.
HomePlug Powerline Alliance
Not-for-profit corporation formed to provide a forum for the creation of open specifications for high speed home powerline networking products and services.
Supposedly works at 14Mbps
Don’t turn on a blow dryer…
Newly released spec’s fix power spikes
WLAN is not all you need to know…
Third Generation Cell service will provide…..???
Reality: WLAN will deliver mobile high-speed ahead of 3G 802.11b/WiFi 50 500 1 000 10 000 50 000 100 000 Transmission rate (kbit/s) Terminal device location HomeRF Bluetooth Fixed LAN Blackberry (US) HomeRF Bluetooth 802.11a and HiperLAN2 UMTS GPRS GSM