View source for Wi-Fi

From Navas Wireless Wiki

← Wi-Fi

You do not have permission to edit this page, for the following reason:

---

You can view and copy the source of this page.

{{Welcome}} {{GoogleSearch}} {{Contributions}} {{Donate}} '''This article covers the practical aspects of wireless access to the Internet via Wi-Fi.''' {{Wi-Fi Articles}} == Introduction to Wi-Fi == [[Image:Wi-Fi Logo.svg.png|thumb|Wi-Fi logo]] [[wikipedia:Wi-Fi|Wi-Fi]] [[wikipedia:wireless|wireless]] [[wikipedia:Computer networking|networks]] provide all the functionality of wired networks, without the need for physical connections. Data is sent over various [[wikipedia:radio frequency|radio frequencies]] depending on the service. Typical Wi-Fi connection speeds are 11 and 54 [[wikipedia:Megabit per second|Mbps]]. In practice, throughput is about half the connection speed. Wireless Networks basically consists of computers equipped with wireless [[wikipedia:Network card|NICs]], which may be [[wikipedia:Universal Serial Bus|USB]], [[wikipedia:Peripheral Component Interconnect|PCI]], [[wikipedia:Mini PCI|Mini PCI]], [[wikipedia:Compact flash|CF]] card, [[wikipedia:PC card|PCMCIA/CardBus]], or other interface. Connectivity to a wired network requires a wireless ''access point'' (AP) used as a [[wikipedia:Bridging (networking)|bridging]] device. Connectivity to the Internet usually requires a ''wireless router'', which includes an access point. AP's are typically located near the centre of the wireless client concentration. == Related Resources == * [[Wikipedia:Wi-Fi]] * [[Wikipedia:IEEE 802.11]] * [http://www.wifi-forum.com/ WiFi-Forum] * [http://www.telecomspace.com/wirelessnw-wifi.html WiFi Resources] * [http://www.practicallynetworked.com/ PracticallyNetworked.com] (reviews, troubleshooting and tutorials) * [http://www.tomsnetworking.com/wireless_tn/index.html Tom's Networking: Wireless] (articles, reviews, and how to's) * [http://scratchpad.wikia.com/wiki/MeshNetworking Locust world mesh networking wiki] * [http://www.amw1.com/tips Setting up a wireless network] * [http://www.microsoft.com/windowsxp/using/networking/default.mspx Home and Small Office Networking with Windows XP] ** [http://www.microsoft.com/windowsxp/using/networking/getstarted/default.mspx Get started with home networking] ** [http://www.microsoft.com/technet/prodtechnol/winxppro/maintain/wifisoho.mspx Configuring Windows XP IEEE 802.11 Wireless Networks for the Home and Small Business] == The Three Rules of Wireless Networking == # It never goes as fast as they say it does<br> # It never goes as far as they say it does<br> # It never sets up as easily as they say it does<br> : [[http://www.smallnetbuilder.com/content/view/24861/99/ Wireless Networking Need To Know 2006]] == Getting Started == '''<big>See ''[http://www.smallnetbuilder.com/content/view/24861/99/ Wireless Networking Need To Know 2006]''</big>''' == Essential Checklist == {| | [[Image:CheckBox.gif]] || '''Use [[wikipedia:Wi-Fi Protected Access|WPA]] security'''. If you don't do this, assume ''you will get [[wikipedia:Hacker (computer security)|hacked]]''. ''[[wikipedia:Wired Equivalent Privacy|WEP]] is essentially worthless''. Replace wireless equipment that doesn't support WPA. Seriously. (''See [[#Wi-Fi Security|Wi-Fi Security]]'') |- | [[Image:CheckBox.gif]] || '''Use a ''strong'' WPA passphrase'''. A good way to do that is with [[wikipedia:Diceware|diceware]] words. (''See [[#What Makes for a Strong Password or Passphrase?|What Makes for a Strong Password or Passphrase?]]'') Write your passphrase on a label and stick it on the bottom of your wireless router so you won't forget it. (If someone gets to your wireless router, you are compromised regardless.) |- | [[Image:CheckBox.gif]] || '''Make your wireless [[wikipedia:Service set identifier|SSID]] unique'''. This helps avoid network collisions. A good way to do this is to use your address, phone number, and/or name for your SSID (making it easy for you to be contacted if something is wrong with your wireless network). |- | [[Image:CheckBox.gif]] || '''Don't bother with SSID hiding or [[wikipedia:MAC address|MAC address]] filtering'''. They ''don't do any real good'' (improve security) but they can ''cause you grief''. (''See [[#Wi-Fi Security Myths|Wi-Fi Security Myths]]'') |- | [[Image:CheckBox.gif]] || '''Turn off [[wikipedia:Universal Plug and Play|Universal Plug and Play]]''' (UPnP) in your wireless router. Because most consumer-grade wireless routers lack UPnP [[wikipedia:Authentication|authentication]] they are vulnerable to attack. (''See [[wikipedia:Universal Plug and Play#Lack of Authentication|Problems with UPnP, Lack of Authentication]]'') |- | [[Image:CheckBox.gif]] || '''Set a ''strong'' password''' on the administration interface of your wireless router. Again, [[wikipedia:Diceware|diceware]] is a good way to do that. |- | [[Image:CheckBox.gif]] || '''Turn off remote administration.''' If your wireless router supports remote administration, ''turn it off'' (unless you really know what you're doing). |- | [[Image:CheckBox.gif]] || '''Configure Windows ''not'' to connect to open networks automatically.''' See [http://compnetworking.about.com/od/wirelesshotspots/qt/noautoconnect.htm Do Not Auto-Connect to Open Wi-Fi Networks] |- | [[Image:CheckBox.gif]] || '''On unsecured Wi-Fi use [[#VPN|VPN]]''' (Virtual Private Networking). Otherwise your wireless traffic can be ''snooped and compromised''. ''(See [[Wi-Fi How To#Secure Internet access in a public hotspot|Secure Internet access in a public hotspot]])'' |} == Wi-Fi Network Types == === Infrastructure === [[Image:Infrastructure.png|thumb|right|Star topology of<br>Infrastructure WLAN]] The [[wikipedia:Network topology|network topology]] of an Infrastructure [[wikipedia:Wireless LAN|Wireless LAN]] (WLAN) is a [[wikipedia:Point-to-multipoint|point-to-multipoint]] ''[[wikipedia:Star network|star]]'', with a single central controller (wireless access point or wireless router), and one or more wireless clients. * Clients can connect to one and only one access point, and not to other clients. * An access point can only connect to clients, not to other access points. Some products can be switched between different modes; ''e.g., ''either an access point or a client bridge, but not both at the same time. Most Wi-Fi WLANs are Infrastructure. === Ad Hoc === [[Image:AdHoc.png|thumb|right|Full Connected topology<br>of Ad Hoc WLAN]] The [[wikipedia:Network topology|network topology]] of an [[wikipedia:Mobile ad-hoc network|Ad Hoc]] [[wikipedia:Wireless LAN|Wireless LAN]] (WLAN) is fully connected matrix, with two or more wireless clients connecting to each other, without any central controller. Connecting an Ad Hoc network to other networks (''e.g.,'' the public [[wikipedia:Internet|Internet]]) typically involves [[wikipedia:Network bridge|bridging]] or [[wikipedia:Routing|routing]] in one of the wireless clients (''e.g.,'' [http://support.microsoft.com/kb/234815/ Windows Internet Connection Sharing]) to some other network connection. == Wi-Fi Channels == Wi-Fi uses spectrum near 2.4 GHz, which is standardized and ''unlicensed'' by international agreement, although the exact frequency allocations vary slightly in different parts of the world, as does maximum permitted power. However, channel numbers are standardized by frequency throughout the world, so authorized frequencies can be identified by channel numbers. <table border="0" cellpadding="0" cellspacing="0"> <tr> <td>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td> <td> <table style="font-size: 90%; line-height: 1.1em;" border="1" cellpadding="0" cellspacing="0"> <tr> <th colspan="8" bgcolor="#ffffee">Wi-Fi Channels </th> </tr> <tr> <th bgcolor="#ffffee">&nbsp;Channel&nbsp; </th> <th bgcolor="#ffffee">&nbsp;Center Freq (GHz)&nbsp; </th> <th bgcolor="#ffffee">&nbsp;Americas&nbsp; </th> <th bgcolor="#ffffee">&nbsp;EMEA&nbsp; </th> <th bgcolor="#ffffee">&nbsp;France&nbsp; </th> <th bgcolor="#ffffee">&nbsp;Israel&nbsp; </th> <th bgcolor="#ffffee">&nbsp;China&nbsp; </th> <th bgcolor="#ffffee">&nbsp;Japan&nbsp; </th> </tr> <tr> <td align="center" bgcolor="#ffffee">1 </td> <td align="center" bgcolor="#ffffee">2.412 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">2 </td> <td align="center" bgcolor="#ffffee">2.417 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">3 </td> <td align="center" bgcolor="#ffffee">2.422 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">4 </td> <td align="center" bgcolor="#ffffee">2.427 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">5 </td> <td align="center" bgcolor="#ffffee">2.432 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">6 </td> <td align="center" bgcolor="#ffffee">2.437 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">7 </td> <td align="center" bgcolor="#ffffee">2.442 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">8 </td> <td align="center" bgcolor="#ffffee">2.447 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">9 </td> <td align="center" bgcolor="#ffffee">2.452 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">10 </td> <td align="center" bgcolor="#ffffee">2.457 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">11 </td> <td align="center" bgcolor="#ffffee">2.462 </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">12 </td> <td align="center" bgcolor="#ffffee">2.467 </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">13 </td> <td align="center" bgcolor="#ffffee">2.472 </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">Y </td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> </tr> <tr> <td align="center" bgcolor="#ffffee">14 </td> <td align="center" bgcolor="#ffffee">2.484 </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">&nbsp; </td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">&nbsp;</td> <td align="center" bgcolor="#ffffee">Y </td> </tr> </table> </td> </tr> </table> * EMEA = Europe, Middle East and Asia (except where otherwise specified) * Maximum permitted power varies by region. * Channel spacing is 0.005 GHz (5 MHz), except for channel 14 (which is ignored for much that follows). * Each channels overlaps its neighbors, with the amount of interference decreasing the farther apart they are. * Most interference is with the two adjacent channels in each direction (above and below); ''e.g., ''channel 6 mostly interferes with channels 4, 5, 7 and 8. * There is significant interference with two more channels in each direction; ''e.g., '' channel 6 also has significant interference with channels 2, 3, 9 and 10. * There can even be some interference beyond four channels in each direction, particularly with strong transmitters; ''e.g., '' channel 6 can interfere with channels 1 and 11. * As a good rule of thumb, there should be minimal interference between channels that are ''five numbers apart'', except channel 14, which has minimal interference with other channels. * In the USA: ** There are ''three minimum interference channels'': 1, 6, 11. ** For four channels with somewhat more interference that may still be usable, channels can be three or four numbers apart: <table border="0" cellpadding="0" cellspacing="0" style="font-size:90%; line-height:1.1em;"> <tr> <td width="20%"></td> <td> <table border="1" cellspacing="0" cellpadding="2" width="100%"> <tr> <th bgcolor="#FFFFEE" nowrap>Option #1</th> <th bgcolor="#FFFFEE" nowrap>Option #2</th> <th bgcolor="#FFFFEE" nowrap>Option #3</th> </tr> <tr> <td align="center" bgcolor="#FFFFEE" nowrap>1, 4, 7, 11</td> <td align="center" bgcolor="#FFFFEE" nowrap>1, 4, 8, 11</td> <td align="center" bgcolor="#FFFFEE" nowrap>1, 5, 8, 11</td> </tr> </table> </td> </tr> </table> References: * [http://www.itu.int/ITU-T/wtsa-04/files/itinfo_lan.doc Channels, Power Levels, and Antenna Gains]. ''Cisco Aironet 1200 Series Access Point Software Configuration Guide for VxWorks. ''Retrieved on 2007-06-18. * Mitchell Burton (Cirond Technologies). [http://www.techonline.com/community/ed_resource/tech_paper/21668 Channel Overlap Calculations for 802.11b Networks]. (PDF) ''White Paper. ''TechOnLine (registration required but free). Retrieved on 2006-06-14. * John Ross. [http://www.nostarch.com/download/wifi_01.pdf How Wi-Fi Works]. (PDF) ''The Book of Wi-Fi (ISBN 1-886411-45-X). ''No Starch Press (March 2003, 288 pp). Retrieved on 2006-06-14. * [[Wikipedia:IEEE 802.11#Channels and international compatibility]] == Wi-Fi Hardware == === Wireless Access Point === A Wireless Access Point (AP) is the central bridge device used in an Infrastructure (as opposed to Ad Hoc) wireless network. (See [[Wi-Fi#Wi-Fi Network Types|Wi-Fi Network Types]]) Traffic from the wireless side of the bridge is sent to the [[wikipedia:Ethernet|Ethernet]] (wired) side of the bridge, and ''vice versa''. The wireless access point controls all traffic with wireless client radios. '''Note''': A wireless router, which is often less expensive than a wireless access point, can be configured to work as just a wireless access point -- see [[Wi-Fi How To#Use a wireless router as a wireless access point|Wi-Fi How To Use a wireless router as a wireless access point]]. === Wireless Router === A wireless router typically consists of three sections: # ''[[wikipedia:Ethernet|Ethernet]] [[wikipedia:Router|router]]'', including: #* [[wikipedia:Dynamic Host Configuration Protocol|DHCP]] client and server #* [[wikipedia:Network address translation|NAT]]([[wikipedia:Port address translation|PAT]]) #* [[wikipedia:Firewall (networking)|Firewall]] (sometimes, not always -- ''NAT alone is '''not''' a real firewall'') # ''Ethernet [[wikipedia:Network switch|switch]]'' # ''Wireless access point'' (radio) Some boxes also include either: * [[wikipedia:Digital Subscriber Line|DSL]] [[wikipedia:Modem|modem]] * [[wikipedia:Cable modem|Cable modem]] '''Note''': A wireless router, which is often less expensive than a wireless access point, can be configured to work as just a wireless access point -- see [[Wi-Fi How To#Use a wireless router as a wireless access point|Wi-Fi How To Use a wireless router as a wireless access point]]. === Wireless Bridge === All [[wikipedia:IEEE 802.11|802.11]] wireless is [[wikipedia:Bridging (networking)|bridging]], where everything is done on [[wikipedia:Data link layer|Layer 2]]. [[wikipedia:IP address|IP addresses]] are used only for configuration of the access points. [[wikipedia:Wi-Fi|Wi-Fi]] encapsulates [[wikipedia:IEEE 802.3|802.3 Ethernet]] [[wikipedia:Packet|packets]] inside 802.11 wireless packets. ==== Wireless Bridge Types ==== * Single [[wikipedia:MAC address|MAC address]] client adapter : Common client radio used in workstations, laptops, and PDA's. Limited to connecting one computer to an infrastructure access point. * Multiple MAC address client adapter : Client wireless adapter that can bridge more than one MAC address. Used for connecting more than one computer via a single wireless link to an infrastructure access point. * Point-to-point wireless bridge : Two identical radios used to connect two networks. Same as transparent bridge. Will bridge more than one MAC address. * Transparent bridges. : Bridges more than one MAC address. Same as point to point bridge. * Point-to-multipoint wireless bridge : Three or more identical radios used to connect multiple networks. Bridge more than one MAC address * Workgroup bridge : Bridges a limited number of MAC addresses (usually 4, 8, or 16) to an infrastructure access point. (Examples: 3Com 3CRWE675075, 3CRWE83096A, Cisco AIR-WGB352) * Game adapter : Muddled marketing term for either a workgroup bridge or single MAC address client adapter. Bridges an indeterminant number of MAC addresses. Some do one MAC, some do more. Good luck. * Wireless [[wikipedia:Repeater|repeater]] : [[wikipedia:Store and forward|Store-and-forward]] repeater. Repeats all packets it hears for a configured [[wikipedia:Service set identifier|SSID]]. Also repeats all broadcasts. Used to extend the range or coverage of a wireless network. * [[wikipedia:Wireless Distribution System|WDS]] bridge : Simultaneously act as a bridge and as an access point. Used to extend the range or coverage of a network. Wireless users can connect to any WDS bridge as if were an access point. WDS bridge radios talk to each other as if they were transparent bridge radios. * Wireless [[wikipedia:Ethernet|Ethernet]] [[wikipedia:Network switch|switch]] : Multiple simple access point radios connected to a central intelligent switch. Offers centralized management and monitoring. Very easy to expand. Note that a switch is a bridge with more than two ports. ==== Wireless Ethernet Bridges ==== ''Note: There are '''limits''' on how many units ([[wikipedia:MAC address|MAC addresses]]) these products are able to bridge (even with a separate wired hub or switch). Some (which may be called "game adapter") are only able to bridge a '''single''' MAC address. Some (but not necessarily all) bridges able to handle more than one MAC address are identified with '''multi''', with a number in parentheses if the specific limit is known. This information may '''not''' be reliable, and should be '''verified''' before making a purchase!'' * '''Actiontec''' ** [http://www.actiontec.com/products/home_networking/54mbps_eth_adapter/index.php 54 Mbps Wireless Ethernet Adapter] * '''Airlink''' ** [http://www.airlink101.com/products/ap411w.php AP411W Super G Wireless Access Point] '''''multi''''' ** [http://www.airlink101.com/products/ap421w.php AP421W Super G Multi-function Access Point] '''''multi''''' ** [http://www.airlink101.com/products/ap431w.php AP431W Super G Multi-function Access Point] '''''multi''''' * '''Alfa Network''' ** [http://dplanet.biz/alfa.com/ AIP-W610H High-Power 400mW 802.11b/g Router] '''''multi'''''<br>(support for access point, client bridge, WDS, and access point + WDS modes) * '''Belkin''' ** [http://catalog.belkin.com/IWCatProductPage.process?Product_Id=136486 F5D7130 Wireless G Access Point] '''''multi''''' ** [http://catalog.belkin.com/IWCatProductPage.process?Product_Id=154416 F5D7330 Wireless G Gaming Adapter] * '''Buffalo''' ** [http://www.buffalotech.com/products/product-detail.php?productid=118&categoryid=29 WLI-TX4-G54HP Wireless-G MIMO Performance Ethernet Converter] '''''multi''''' * '''D-Link''' ** [http://www.dlink.com/products/?pid=383 DGL-3420 Wireless 108AG Gaming Adapter] ** [http://www.dlink.com/products/?pid=482 DPR-1260 RangeBooster G Multifunction Print Server]<br>''Can be used to bridge an Ethernet device.'' ** [http://www.dlink.com/products/?pid=292 DWL-2100AP High Speed 2.4GHz (802.11g) Wireless 108Mbps Access Point] '''''multi''''' ** [http://www.dlink.com/products/?pid=303 DWL-2700AP Wireless 802.11g Outdoor AP/Bridge] '''''multi''''' ** [http://www.dlink.com/products/?pid=376 DWL-7700AP Wireless AG Outdoor AP/Bridge] '''''multi''''' ** [http://support.dlink.com/products/view.asp?productid=DWL%2D810%2B DWL-810+ Ethernet to Wireless Bridge] '''''multi''''' ** [http://support.dlink.com/products/view.asp?productid=DWL%2DG810 DWL-G810 Ethernet to Wireless Bridge] ** [http://www.dlink.com/products/?pid=333 DWL-G820 High-Speed Wireless Gaming Adapter] * '''Hawking''' ** [http://www.hawkingtech.com/products/productlist.php?CatID=19&FamID=82&ProdID=177 HWBA54G Wireless-G Multi-Function AP/Bridge] '''''multi''''' * '''Linksys''' ** [http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1118334782530&pagename=Linksys%2FCommon%2FVisitorWrapper WET54G Wireless-G Ethernet Bridge] '''''multi''''' ** [http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1115416829491&packedargs=site%3DUS&pagename=Linksys%2FCommon%2FVisitorWrapper WGA54AG Wireless A/G Game Adapter] ** [http://www.linksys.com/servlet/Satellite?c=L_Product_C2&childpagename=US%2FLayout&cid=1115416826619&packedargs=site%3DUS&pagename=Linksys%2FCommon%2FVisitorWrapper WGA54G Wireless-G Game Adapter] * '''Motorola''' ** [http://broadband.motorola.com/consumers/products/we800g/ WE800G Wireless Ethernet Bridge] * '''NETGEAR''' ** [http://www.netgear.com/Products/WirelessAccessPoints/WirelessAccessPoints/WAG102.aspx?detail=Specifications WAG102 ProSafe Dual Band Wireless Access Point] '''''multi''''' ** [http://www.netgear.com/Products/WirelessAccessPoints/WirelessAccessPoints/WAG302.aspx?detail=Specifications WAG302 ProSafe Dual Band Wireless Access Point] '''''multi''''' ** [http://www.netgear.com/Products/WirelessAccessPoints/WirelessAccessPoints/WG102.aspx?detail=Specifications WG102 Prosafe 802.11g Wireless Access Point] '''''multi''''' ** [http://www.netgear.com/Products/WirelessAccessPoints/WirelessAccessPoints/WG302.aspx?detail=Specifications WG302 Prosafe 802.11g Wireless Access Point] '''''multi''''' ** [http://www.netgear.com.au/products/prod_details.asp?prodID=209 WGE101 54 Mbps Wireless Ethernet Bridge] '''''multi''''' ** [http://www.netgear.com/Products/PrintServers/WirelessPrintServers/WGPS606.aspx WGPS606 54Mbps Wireless USB print server with 4-port switch] '''''multi'''''<br>''Can be used to bridge Ethernet devices.'' * '''SMC''' ** [http://www.smc.com/index.cfm?event=viewProduct&localeCode=EN_USA&cid=94&scid=&pid=365 SMC2582W-B EliteConnect Wireless Bridge] '''''multi''''' ** [http://www.smc.com/index.cfm?event=viewProduct&localeCode=EN_USA&cid=94&scid=&pid=1487 SMC2585W-G EliteConnect Wireless Bridge] '''''multi''''' ** [http://www.smc.com/index.cfm?event=viewProduct&localeCode=EN_USA&cid=94&scid=&pid=373 SMC2586W-G EliteConnect Wireless Bridge] '''''multi''''' ** [http://www.smc.com/index.cfm?event=viewProduct&localeCode=EN_USA&cid=5&scid=&pid=586 SMC2870W EZ Connect g Wireless Ethernet Bridge] '''''multi''''' ** [http://www.smc.com/index.cfm?event=viewProduct&localeCode=EN_USA&cid=5&scid=84&pid=1474 SMCWEBT-G EZ Connect g Wireless Ethernet Bridge] '''''multi''''' === Adapter Types === * [[Wikipedia:Peripheral Component Interconnect|PCI]] * [[Wikipedia:Mini PCI|Mini PCI]] * [[Wikipedia:Universal Serial Bus|USB]] * [[Wikipedia:PC card|PC Card]] === Link Calculations === The easiest way to do this is by example. Your setup and numbers will vary. This is the [[wikipedia:Best, worst and average case|best case]] solution, with no consideration for atmospherics, [[wikipedia:Fresnel zone|Fresnel zone]] edge diffraction, folliage attenuation, and non-line of sight effect. [[wikipedia:Fade margin|Fade margin]] only gets worse, never better. We'll use a pair of Linksys [http://www.linksysinfo.org/modules.php?name=Content&pa=showpage&pid=6 WRT54G v4] 802.11g with [http://www.dd-wrt.com DD-WRT] alternative firmware setup as a transparent bridge. This makes it easy because both sides are the same. The transmit output is about +17 [[wikipedia:DBm|dBm]]. The WRT54G will be mounted in a weatherproof box somewhere near the antenna with a single 3 ft cable (pigtail) using LMR-240 [[wikipedia:Coaxial cable|coax]] with a loss of about 4 [[wikipedia:Decibel|dB]] including connectors. Next, we gotta do some guesswork. I'll assume that we can live with about 6 [[wikipedia:Megabit per second|Mbits/sec]] [[wikipedia:Throughput|thruput]]. That means the connection speed will be about twice that or 12 Mbits/sec. The receiver sensitivity varies with the speed and modulation type. The following is from the Dlink DI-624 datasheet but is close enough for most similar 802.11g radios: <table border="0" cellpadding="0" cellspacing="0" style="font-size:90%; line-height:1.1em;"> <tr> <td width="30"> </td> <td> <div align="center"> <table border="1" cellspacing="0" width="100%" cellpadding="2"> <tr height="17" > <th bgcolor="#FFFFEE" >Mbps</th> <th bgcolor="#FFFFEE" >Type</th> <th bgcolor="#FFFFEE" >PER</th> <th bgcolor="#FFFFEE" >dBm</th> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >54</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-68</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >48</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-68</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >36</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-75</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >24</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-79</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >18</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-82</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >12</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-84</td> </tr> </table> </div> </td> <td width="20" ></td> <td> <div align="center"> <table border="1" cellspacing="0" width="100%" cellpadding="2"> <tr height="17" > <th bgcolor="#FFFFEE" >Mbps</th> <th bgcolor="#FFFFEE" >Type</th> <th bgcolor="#FFFFEE" >PER</th> <th bgcolor="#FFFFEE" >dBm</th> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >11</td> <td align="center" bgcolor="#FFFFEE" >CCK</td> <td align="center" bgcolor="#FFFFEE" >8%</td> <td align="center" bgcolor="#FFFFEE" >-82</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >9</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-87</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >6</td> <td align="center" bgcolor="#FFFFEE" >OFDM</td> <td align="center" bgcolor="#FFFFEE" >10%</td> <td align="center" bgcolor="#FFFFEE" >-88</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >5.5</td> <td align="center" bgcolor="#FFFFEE" >CCK</td> <td align="center" bgcolor="#FFFFEE" >8%</td> <td align="center" bgcolor="#FFFFEE" >-85</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >2</td> <td align="center" bgcolor="#FFFFEE" >QPSK</td> <td align="center" bgcolor="#FFFFEE" >8%</td> <td align="center" bgcolor="#FFFFEE" >-86</td> </tr> <tr height="17" > <td align="center" bgcolor="#FFFFEE" >1</td> <td align="center" bgcolor="#FFFFEE" >BPSK</td> <td align="center" bgcolor="#FFFFEE" >8%</td> <td align="center" bgcolor="#FFFFEE" >-89</td> </tr> </table> </div> </td> </tr> </table> 12 Mbps connect speed thus sets the receiver sensitivity at -84 dBm. '''PER''' (Packet Error Rate) is similar to BER (Bit Error Rate) but is easier to measure. You would not want to operate at a 10% PER error rate. 1 in 10 packets trashed is useable, but no fun. This is approximately the same as a BER of 1E10⁵, which is one of the common reference levels for measuring receiver sensitivity. Again, these are measurement reference levels, not operating points. Next, we must guess the fade margin. Fade margin or system operating margin is how much stronger the operating level is above the receiver reference level. 20 dB is considered to be a good minimum. In other words, your operating signal level must be 100 times stronger than the receiver sensitivity or the link is going to be flaky and unreliable. The relationship between fade margin and reliability is: <table border="0" cellpadding="0" cellspacing="0" style="font-size:90%; line-height:1.1em;"> <tr> <td width="30"></td> <td> <table border=1 cellpadding=2 cellspacing=0 width=100%> <tr height=17> <th bgcolor="#FFFFEE">SOM dB</th> <th bgcolor="#FFFFEE">Reliability %</th> <th bgcolor="#FFFFEE">Downtime per year</th> </tr> <tr height=17> <td> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=right bgcolor="#FFFFEE">8</td> <td bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">18</td> <td bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">28</td> <td bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">38</td> <td bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">48</td> <td bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">58</td> <td bgcolor="#FFFFEE">&nbsp;</td> </tr> </table> </td> <td> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=right bgcolor="#FFFFEE">90</td> <td bgcolor="#FFFFEE"></td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">99</td> <td bgcolor="#FFFFEE"></td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">99</td> <td bgcolor="#FFFFEE">.9</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">99</td> <td bgcolor="#FFFFEE">.99</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">99</td> <td bgcolor="#FFFFEE">.999</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">99</td> <td bgcolor="#FFFFEE">.9999</td> </tr> </table> </td> <td align=right> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=right bgcolor="#FFFFEE">876</td> <td bgcolor="#FFFFEE"></td> <td bgcolor="#FFFFEE">hours</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">88</td> <td bgcolor="#FFFFEE"></td> <td bgcolor="#FFFFEE">hours</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">8</td> <td bgcolor="#FFFFEE">.8</td> <td bgcolor="#FFFFEE">hours</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">53</td> <td bgcolor="#FFFFEE"></td> <td bgcolor="#FFFFEE">minutes</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">5</td> <td bgcolor="#FFFFEE">.3</td> <td bgcolor="#FFFFEE">minutes</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">32</td> <td bgcolor="#FFFFEE"></td> <td bgcolor="#FFFFEE">seconds</td> </tr> </table> </td> </tr> </table> </td> </tr> </table> 99% reliability might sound great, but that means your link will be useless for 1% of the year, or 3.6 days per year. Don't go below 20 dB fade margin, which is 70 hours of downtime per year. Plugging the above guesswork into a suitable [http://www.terabeam.com/support/calculations/som.php Link Calculator] and trying various [[wikipedia:Antenna gain|antenna gains]] until we get a 20 dB fade margin: <table border="0" cellpadding="0" cellspacing="0" width="60%" style="font-size:90%; line-height:1.1em;"> <tr> <td width="30"></td> <td> <table border="1" cellpadding="0" cellspacing="0" width="100%"> <tr> <td> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>TX power&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>TX coax loss&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>TX ant gain&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>Distance&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>RX ant gain&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>RX coax loss&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>RX sens&nbsp;</td> </tr> <tr> <td align="right" bgcolor="#FFFFEE" nowrap>Fade margin&nbsp;</td> </tr> </table> </td> <td> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;+15 dBm</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;4 dB (3 ft LMR-240 plus a mess of connectors)</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;unknown</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;2 miles</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;unknown</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;4 dB (same at other end)</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;-84 dBm (at 12 Mbits/sec)</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;20 dB</td> </tr> </table> </td> </tr> </table> </td> </tr> </table> yields a minimum antenna gain of +21 dBi. Any less than +21 dBi antenna gain will result in insufficient fade margin and a corresponding loss in link reliability. That makes the required antenna to be a [[wikipedia:Parabolic antenna|dish]]. We can use a lower gain antenna by running at a slower speed, shorter coax, or more transmit power at ''both'' ends. '''Online link calculators:''' * [http://www.terabeam.com/support/calculations/som.php System Operating Margin (Terabeam Wireless)] * [http://my.athenet.net/~multiplx/cgi-bin/wireless.main.cgi Wireless Network Link Analysis (Green Bay Professional Packet Radio)] * [http://www.connect802.com/antenna_c_main.php Antenna System Designer (Connect802)] === Performance and Speed === Wireless connection speed and thruput are quite different. The wireless may offer a connection speed of 54 Mbits/sec, but the actual thruput is considerably less, typically less than half. That's because of management packet overhead, [[wikipedia:IEEE 802.11|802.11b]] compatibility, inter-symbol gaps, and necessary timing delays. Also, note that wireless is [[wikipedia:Duplex (telecommunications)|half-duplex]], where only one radio in a given airspace can transmit at a time. This is taken from an [http://www.atheros.com/pt/atheros_range_whitepaper.pdf Atheros paper] with some additions and corrections. <table border="0" cellpadding="0" cellspacing="0" style="font-size:90%; line-height:1.1em;"> <tr> <td width="30"></td> <td> <table border=1 cellpadding=2 cellspacing=0 width="100%"> <tr height=17> <th bgcolor="#FFFFEE">Wi-Fi type</th> <th bgcolor="#FFFFEE">Non-overlapping<br> Channels</th> <th bgcolor="#FFFFEE">Modulation</th> <th bgcolor="#FFFFEE">Max Link</th> <th bgcolor="#FFFFEE">Max TCP</th> <th bgcolor="#FFFFEE">Max UDP</th> </tr> <tr height=17> <td bgcolor="#FFFFEE" align="left" nowrap>&nbsp;802.11b only</td> <td align=center bgcolor="#FFFFEE">&nbsp; 3</td> <td align="center" bgcolor="#FFFFEE">CCK</td> <td align=center bgcolor="#FFFFEE">&nbsp; 11</td> <td align=center bgcolor="#FFFFEE">&nbsp; 5.9</td> <td align=center bgcolor="#FFFFEE">&nbsp; 7.1</td> </tr> <tr height=17> <td bgcolor="#FFFFEE" align="left" nowrap>&nbsp;802.11g with 802.11b&nbsp;</td> <td align=center bgcolor="#FFFFEE">&nbsp; 3</td> <td align="center" bgcolor="#FFFFEE">OFDM/CCK</td> <td align=center bgcolor="#FFFFEE">&nbsp; 54</td> <td align=center bgcolor="#FFFFEE">14.4</td> <td align=center bgcolor="#FFFFEE">19.5</td> </tr> <tr height=17> <td bgcolor="#FFFFEE" align="left" nowrap>&nbsp;802.11g only</td> <td align=center bgcolor="#FFFFEE">&nbsp; 3</td> <td align="center" bgcolor="#FFFFEE">OFDM</td> <td align=center bgcolor="#FFFFEE">&nbsp; 54</td> <td align=center bgcolor="#FFFFEE">24.4</td> <td align=center bgcolor="#FFFFEE">30.5</td> </tr> <tr height=17> <td bgcolor="#FFFFEE" align="left" nowrap>&nbsp;802.11g turbo</td> <td align=center bgcolor="#FFFFEE">&nbsp; 1</td> <td align="center" bgcolor="#FFFFEE">OFDM</td> <td align=center bgcolor="#FFFFEE">108</td> <td align=center bgcolor="#FFFFEE">42.9</td> <td align=center bgcolor="#FFFFEE">54.8</td> </tr> <tr height=17> <td bgcolor="#FFFFEE" align="left" nowrap>&nbsp;802.11a</td> <td align=center bgcolor="#FFFFEE">13</td> <td align="center" bgcolor="#FFFFEE">OFDM</td> <td align=center bgcolor="#FFFFEE">&nbsp; 54</td> <td align=center bgcolor="#FFFFEE">24.4</td> <td align=center bgcolor="#FFFFEE">30.5</td> </tr> <tr height=17> <td bgcolor="#FFFFEE" align="left" nowrap>&nbsp;802.11a turbo</td> <td align=center bgcolor="#FFFFEE">&nbsp; 6</td> <td align="center" bgcolor="#FFFFEE">OFDM</td> <td align=center bgcolor="#FFFFEE">108</td> <td align=center bgcolor="#FFFFEE">42.9</td> <td align=center bgcolor="#FFFFEE">54.8</td> </tr> </table> </td> </tr> </table> The paper claims that encryption is enabled for these calculations, but the numbers seem to indicate that these number are for encryption disabled. (Don't know for sure.) The maximum [[wikipedia:Transmission Control Protocol|TCP]] and maximum [[wikipedia:User Datagram Protocol|UDP]] are the theoretical maximum [[wikipedia:Throughput|throughput]] rates. No calculations for Turbo and SuperG modes yet. There is also a relationship between speed and range. The following table is from a paper by Intel on [ftp://download.intel.com/business/bss/infrastructure/wireless/deployment/hotspot.pdf wireless hotspot deployment] for 802.11b/g. <table border="0" cellpadding="0" cellspacing="0" style="font-size:90%; line-height:1.1em;"> <tr> <td width="30"></td> <td> <table border=1 cellpadding=2 cellspacing=0 width=100%> <tr height=17> <th width=50% bgcolor="#FFFFEE" nowrap>Rate Mbps</th> <th width=50% bgcolor="#FFFFEE" nowrap>Range ft</th> </tr> <tr height=17> <td bgcolor="#FFFFEE"> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=right bgcolor="#FFFFEE">1</td> <td bgcolor="#FFFFEE"></td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">2</td> <td bgcolor="#FFFFEE"></td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">5</td> <td bgcolor="#FFFFEE">.5</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">6</td> <td bgcolor="#FFFFEE"></td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">9</td> <td bgcolor="#FFFFEE"></td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">11</td> <td bgcolor="#FFFFEE"></td> </tr> </table> </td> <td bgcolor="#FFFFEE"> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=center bgcolor="#FFFFEE">350</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">250</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">180</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">300</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">250</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">150</td> </tr> </table> </td> </tr> </table> </td> <td width="20"></td> <td> <table border=1 cellpadding=2 cellspacing=0 width=100%> <tr height=17> <th width=50% bgcolor="#FFFFEE" nowrap>Rate Mbps</th> <th width=50% bgcolor="#FFFFEE" nowrap>Range ft</th> </tr> <tr height=17> <td bgcolor="#FFFFEE"> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=right bgcolor="#FFFFEE">12</td> <td align=left bgcolor="#FFFFEE">&nbsp;&nbsp;&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">18</td> <td align=left bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">24</td> <td align=left bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">36</td> <td align=left bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">48</td> <td align=left bgcolor="#FFFFEE">&nbsp;</td> </tr> <tr height=17> <td align=right bgcolor="#FFFFEE">54</td> <td align=left bgcolor="#FFFFEE">&nbsp;</td> </tr> </table> </td> <td bgcolor="#FFFFEE"> <table border=0 cellpadding=0 cellspacing=0 width=100%> <tr height=17> <td align=center bgcolor="#FFFFEE">200</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">170</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">140</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">100</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">&nbsp; 95</td> </tr> <tr height=17> <td align=center bgcolor="#FFFFEE">&nbsp; 90</td> </tr> </table> </td> </tr> </table> </td> </tr> </table> The rather optimistic ranges listed are probably with a better than standard [[wikipedia:Omnidirectional antenna|omnidirectional antenna]] and with unobstructed [[wikipedia:Line of sight|line of sight]]. There are similar charts in the Intel [[wikipedia:Hotspot (wifi)|Wi-Fi hotspot]] paper for other [[wikipedia:Radio frequency|frequencies]] and [[wikipedia:Communications protocol|protocols]]. === Attenuation === Solid objects greatly [[wikipedia:Attenuation|attenuate]] (reduce) Wi-Fi radio signals, so clear line of sight is best. The amount of attenuation is expressed in dB, where each 3 dB of attenuation is a power loss of 1/2. ==== Indoor ==== :{| border="1" cellpadding="2" cellspacing="0" width="60%" style="background:#FFFFEE; font-size:90%; line-height:1.1em;" |+'''Attenuation Properties of Common Building Materials''' !Building Material !2.4 GHz Attenuation |- |Solid Wood Door 1.75" |align="center"|&nbsp;&nbsp;6 dB |- |Hollow Wood Door 1.75" |align="center"|&nbsp;&nbsp;4 dB |- |Interior Office Door w/Window 1.75"/0.5" |align="center"|&nbsp;&nbsp;4 dB |- |Steel Fire/Exit Door 1.75" |align="center"|13 dB |- |Steel Fire/Exit Door 2.5" |align="center"|19 dB |- |Steel Rollup Door 1.5" |align="center"|11 dB |- |Brick 3.5" |align="center"|&nbsp;&nbsp;6 dB |- |Concrete Wall 18" |align="center"|18 dB |- |Cubical Wall (Fabric) 2.25" |align="center"|18 dB |- |Exterior Concrete Wall 27" |align="center"|53 dB |- |Glass Divider 0.5" |align="center"|12 dB |- |Interior Hollow Wall 4" |align="center"|&nbsp;&nbsp;5 dB |- |Interior Hollow Wall 6" |align="center"|&nbsp;&nbsp;9 dB |- |Interior Solid Wall 5" |align="center"|14 dB |- |Marble 2" |align="center"|&nbsp;&nbsp;6 dB |- |Bullet-Proof Glass 1" |align="center"|10 dB |- |Exterior Double Pane Coated Glass 1" |align="center"|13 dB |- |Exterior Single Pane Window 0.5" |align="center"|&nbsp;&nbsp;7 dB |- |Interior Office Window 1" |align="center"|&nbsp;&nbsp;3 dB |- |Safety Glass-Wire 0.25" |align="center"|&nbsp;&nbsp;3 dB |- |Safety Glass-Wire 1.0" |align="center"|13 dB |} :[Source: [http://www.3com.com/other/pdfs/products/en_US/101900.pdf 3Com Wireless Antennas Product Guide]] ==== Outdoor ==== {{TODO}} === Repeaters === {{TODO}} === Antennas === ==== Antenna Manufacturers ==== * [[#Hawking|Hawking]] * [[#Linksys|Linksys]] ==== Do It Yourself ==== * See [[Wikibooks:Wifi:Building an antenna]] * [http://www.ab9il.net/wlan-projects/wifi1.html AB9IL WLAN Antenna Projects] === Manufacturers === ==== Belkin ==== * '''[http://belkin.com Belkin home page]''' ==== Buffalo Technology ==== * '''[http://buffalotech.com Buffalo Technology home page]''' * [http://buffalotech.com/products/product-detail.php?productid=117&categoryid=30 WHR-G54S Wireless-G High Speed Router & Access Point] ** [http://www.gilanet.com/ohlandl/NIC/whr-g54s.html Notes on the Buffalo Technology WHR-G54S] ==== D-Link ==== * '''[http://dlink.com D-Link home page]''' * [ftp://ftp.dlink.com/Gateway/ Firmware downloads] (including [[Wikipedia:Release cycle|beta]] versions) * [http://support.dlink.com/faq/view.asp?prod_id=1457 Product simulators] (user interfaces) ==== Hawking Technology ==== * '''[http://hawkingtech.com Hawking Technology home page]''' * [http://www.hawkingtech.com/products/index.php?CatID=32&FamID=58 High-Gain Range Extending Antennas] * [http://hawkingtech.com//support/details.php?CatID=19&FamID=13&ProdID=147&Rev=M HWR54G Hi-Speed Wireless-G Router] '''''Revision M''''' ** '''BUG:''' Firmware Version 1.0 Release 11 is unable to properly renew DHCP leases on [http://comcast.com/Benefits/CHSIBenefits.asp?LinkID=51 Comcast cable Internet]. '''Fixed in Version 1.1 Release 22'''. As of May 2006, the only way to get this firmware is by an '''[mailto:techsupport@hawkingtech.com?subject=HWR54G%20Rev%20M%20firmware%20Version%201.1%20Release%2022%20(or%20later) email request to Hawking Support]''' ''('''not''' phone)''. ==== Intel ==== * '''[http://www.intel.com/network/connectivity/products/wireless/index.htm Intel Wireless Networking]''' ==== Linksys ==== * '''[http://linksys.com Linksys home page]''' (part of [http://cisco.com Cisco Systems]) * Antennas ** [http://www.linksys.com/servlet/Satellite?blobcol=urldata&blobheadername1=Content-Type&blobheadername2=Content-Disposition&blobheadervalue1=application%2Fpdf&blobheadervalue2=inline%3B+filename%3DHGA7S-DS%252C0.pdf&blobkey=id&blobtable=MungoBlobs&blobwhere=1130803982737&ssbinary=true HGA7S High-Gain (7 dBi) Omni with R-SMA connector] ** [http://www.linksys.com/servlet/Satellite?blobcol=urldata&blobheadername1=Content-Type&blobheadername2=Content-Disposition&blobheadervalue1=application%2Fpdf&blobheadervalue2=inline%3B+filename%3Dhga7t-ds.pdf&blobkey=id&blobtable=MungoBlobs&blobwhere=1130803982775&ssbinary=true HGA7T High-Gain (7 dBi) Omni with R-TNC connector] * [http://www.linksysInfo.org LinksysInfo.org] Good source of information on Linksys products * [http://www.linksysdata.com/ui/ Product simulators] (user interfaces) * [[Wikipedia:WRT54G]] (including related models) ==== Motorola ==== * '''[http://broadband.motorola.com/consumers/home_networking.asp Motorola Home Networking]''' * [http://broadband.motorola.com/consumers/products/wps870g/default.asp WPS870G Wireless Print Server] ** 6/2006: WPA-PSK reportedly doesn't work. Replace product with something else. ==== NETGEAR ==== * '''[http://netgear.com NETGEAR home page]''' * WG511 PC Card ** Version 1 (v1) has about the best range and performance of readily available 802.11g PC Card adapters ** Version 2 (v2), a different design, isn't as good as Version 1. ==== 3Com ==== * '''[http://www.3com.com/wireless 3Com Wireless]''' ==== 2Wire ==== * '''[http://www.2wire.com/ 2Wire home page]''' === 3rd-party Firmware === Replacing the standard firmware in certain wireless routers and access points (''e.g.,'' [[wikipedia:WRT54G|Linksys WRT54GL]]) can provide greatly increased functionality (''e.g.'' [[wikipedia:Hotspot (Wi-Fi)|hotspot]] capability) and improved stability, although a fair amount of technical skill may be needed. For specific features and supported products, see: * '''[http://www.dd-wrt.com/dd-wrtv2/ddwrt.php DD-WRT]''' ** [http://www.howtoforge.com/wifi_hotspot_setup How To Setup a Wi-Fi Hotspot] ** [http://www.sputnik.com/ Sputnik] (for setting up secure hotspots) * '''[http://openwrt.org/ OpenWRT]''' ** [http://www.chillispot.org/ ChilliSpot] (for setting up secure hotspots) ** [http://wiki.openwrt.org/HotspotOpenvpnHowto?highlight=%28HowTo%29 HotspotOpenvpnHowto] (hotspot with private VPN access) ** [http://www.wifitastic.com/ WiFiTastic] (for setting up secure hotspots) * '''[http://www.sveasoft.com/ Sveasoft]''' Replacing the standard firmware in certain wireless routers and access points (''e.g.,'' [[wikipedia:rtl8186|ZyxelP330W]]) can provide greatly increased functionality (''e.g.'' [[wikipedia:Hotspot (Wi-Fi)|hotspot]] capability) and improved stability, although a fair amount of technical skill may be needed. For specific features and supported products, see: * '''[http://rtl8186.sf.net Wive (firmware for rtl8186 SoC based routers)]''' * '''[http://wive-ng.sf.net Wive-NG (next generation firmware for rtl8186 SoC based routers)]''' == Wi-Fi Software == === Connection Managers === Software for rapid changing of network configuration profiles. * [http://www.boingo.com/download.html Boingo Wi-Fi software] (free) * [http://www.mobilenetswitch.com/ Mobile Net Switch] * [http://www.netswitcher.com/ NetSwitcher] === Network Monitors === Monitor network throughout, amount of data sent/received, ''etc.'' Recommended products are shown in bold. * [http://www.snapfiles.com/get/bwvista.html Bandwidth Vista] * [http://www.e-systems.ro/bandwidth_monitor.htm Emsa Bandwidth Monitor] * '''[http://www.snapfiles.com/get/novatrafstats.html MZL & Novatech TrafficStatistic]''' * '''[http://readerror.gmxhome.de/ NetMeter]''' * [http://www.snapfiles.com/get/netmon.html Netmon] * [http://www.snapfiles.com/get/netspeed.html NetSpeed] * [http://www.analogx.com/contents/download/network/nsl.htm NetStat Live] * [http://majorgeeks.com/Network_Traffic_Monitor_d1858.html Network Traffic Monitor] * '''[http://www.snapfiles.com/get/tslanmon.html Tong Software LAN Monitor]''' * [http://www.snapfiles.com/get/itindicator.html Interface Traffic Indicator] === Site Survey Tools === ''See [[Wi-Fi How To#Why and How to do a Site Survey|Why and How to do a Site Survey]]'' * Free tools ** [http://www.kismetwireless.net/ Kismet] ** [http://www.stumbler.net/ Network Stumbler] === WEP cracking === * [http://airsnort.shmoo.com/ Airsnort] == Wi-Fi Speed == * The raw speed reported by your wireless network adapter is ''not'' necessarily a reliable indicator of actual raw speed. The reason is that transmit speed fluctuates according to the wireless error rate, and when the wireless link is idle, unrealistic speed may be reported (since no errors are occuring when the wireless link is idle). * Data can only flow on ''one'' wireless link in ''one'' direction at any one time, which means that the ''maximum data transfer rate will be well below half of the raw wireless network speed''. * To measure Wi-Fi speed, see ''[[Wi-Fi How To#Measure wireless network performance|Wi-Fi How To Measure wireless network performance]]''. == Wi-Fi Safety == === Anti-Virus (free) === ''If you're not already protected, then you're probably already infected!'' '''Resident protection''' * [http://www.free-av.com/ Avira AntiVir Personal Edition Classic] ** Very good, but occasionally pops up a ''nag screen'' *** ''[http://groups.google.com/group/alt.comp.anti-virus/msg/909eb6a8756fd6f0 How to eliminate the nag screen] (Windows XP Pro only)'' * '''[http://comodo.com COMODO Internet Security] (very good, includes very good firewall)''' * [http://free.grisoft.com/ Grisoft AVG Free] ** Not quite as good, but still very good, and ''no nagging'' '''Online scanners''' (good when you think you might be infected) * [http://housecall.trendmicro.com/ Trend Micro HouseCall] * [http://www.pandasoftware.com/products/activescan/ Panda ActiveScan] * [http://www.kaspersky.com/scanforvirus Kaspersky Lab] * [http://us.mcafee.com/root/mfs/ McAfee FreeScan] === Anti-Spyware (free) === ''Run only one resident protection at any given time.<br>(Multiple scanners are OK, and may be needed in difficult cases.)'' * '''[http://www.microsoft.com/athome/security/spyware/software/ Microsoft Defender]''' ** Very good protection ** Only works on [http://www.microsoft.com/genuine/downloads/WhyValidate.aspx?displaylang=en "genuine" Windows] '''Other good anti-spyware''' (''e.g., ''for on-demand scanning) * [http://www.lavasoft.com/software/adaware/ Ad-Aware Free] (not effective against all threats) * [http://www.safer-networking.org/ Spybot Search & Destroy] (not effective against all threats) '''Diagnostic tools for spyware''' * [http://www.tomcoyote.org/hjt/ HijackThis] == Wi-Fi Security == *See: ** [[wikibooks:Wifi:Security|WiFi:Security]] ** [http://www.drizzle.com/~aboba/IEEE/ The Unofficial 802.11 Security Web Page] ** [http://blogs.zdnet.com/Ou/index.php?p=42 Simple advice for securing your home wireless LAN] === Wi-Fi Security Myths === * '''[http://blogs.zdnet.com/Ou/index.php?p=43 The six dumbest ways to secure a wireless LAN]''' (Wireless LAN security hall of shame) ** MAC filtering (absolutely worthless) ** SSID hiding (doesn't really work, causes needless grief) *** [http://www.trusecure.com/cgi-bin/download.cgi?ESCD=W0149&file=wp_ssid_hiding.pdf Debunking the Myth of SSID Hiding] (registration required) ** LEAP authentication (can be rapidly cracked) ** Disable DHCP (waste of time) ** Antenna placement (hackers have better antennas than you do) ** Just use 802.11a or Bluetooth (have nothing to do with security) * '''[http://www.oreillynet.com/pub/a/wireless/excerpt/wirlsshacks_chap1/ Dispelling the Myth of Wireless Security]''' === Intruder Detection === * [http://home.comcast.net/~jay.deboer/airsnare/ AirSnare] === WEP === * See [[Wikipedia:Wired Equivalent Privacy]] (WEP) * ''WEP can be easily cracked and is ''not'' secure. Use WPA instead.'' ** [http://www.smallnetbuilder.com/content/view/24244/98/ How To Crack WEP] ** [http://www.securityfocus.com/infocus/1814 WEP: Dead Again] * WEP keys can usually be entered in either ''ASCII format ''(all letters, numbers, ''etc.'') or ''hex (hexadecimal) format ''(only 0-9 and A-F), and the difference can result in (frustrating) key mismatch. To avoid this problem, ''enter all keys in hex'' (using only symbols 0-9 and A-F). <table border="0" cellpadding="0" cellspacing="0" style="font-size:90%; line-height:1.1em;"> <tr> <td width="40"> </td> <td> <table border="1" cellspacing="0" cellpadding="2"> <tr> <th rowspan="2" bgcolor="#FFFFEE" nowrap> WEP Type (Bits)</th> <th colspan="2" bgcolor="#FFFFEE" nowrap> Number of key characters</th> </tr> <tr> <th bgcolor="#FFFFEE">ASCII</th> <th bgcolor="#FFFFEE">Hex</th> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;WEP64 (40)</td> <td align="center" bgcolor="#FFFFEE">5</td> <td align="center" bgcolor="#FFFFEE">10</td> </tr> <tr> <td bgcolor="#FFFFEE" nowrap>&nbsp;WEP128 (104)</td> <td align="center" bgcolor="#FFFFEE">13</td> <td align="center" bgcolor="#FFFFEE">26</td> </tr> </table> </td> </tr> </table> === WPA === * See [[Wikipedia:Wi-Fi Protected Access]] (WPA) {{Tip|tiptext=WPA can be cracked if a weak passphrase is used!<br>See [[#What Makes for a Strong Password or Passphrase?|What Makes for a Strong Password or Passphrase?]]}} === Universal Plug and Play === Turn off [[wikipedia:Universal Plug and Play|Universal Plug and Play]] (UPnP) in your wireless router. Because most consumer-grade wireless routers lack UPnP [[wikipedia:Authentication|authentication]] they are vulnerable to attack. (''See [[wikipedia:Universal Plug and Play#Lack of Authentication|Problems with UPnP, Lack of Authentication]]'') === SSL/TLS === * [[Wikipedia:Transport Layer Security|Wikipedia:SSL/TLS]] (Secure Sockets Layer/Transport Layer Security) * See: ** [[Wi-Fi How To#Use SSL/TLS for email access|Wi-Fi How To Use SSL/TLS for email access]] ** [[Wi-Fi How To#Use SSL/TLS for sensitive Web pages|Wi-Fi How To Use SSL/TLS for sensitive Web pages]] === Software Firewall === * A good software "[[wikipedia:Firewall (networking)|firewall]]" will protect your computer from network attacks, particularly on [[wikipedia:Encryption|unencrypted]] Wi-Fi networks (''e.g., ''public [[wikipedia:Hotspot (Wi-Fi)|hotspots]]). * If running Microsoft Windows XP: *# Update with SP2 (Service Pack 2), and install ''all'' security updates. *# Make sure the Windows Firewall is enabled for the wireless connection. * Good free software firewalls ** [http://www.personalfirewall.comodo.com/ Comodo Personal Firewall] ** [http://www.sunbelt-software.com/kerio.cfm Sunbelt Kerio Personal Firewall] (full download reverts to free basic version after 30 days) ** [http://www.zonelabs.com/store/content/catalog/products/sku_list_za.jsp?dc=12bms&ctry=US&lang=en&lid=nav_za ZoneAlarm] === VPN === VPN ([[wikipedia:Virtual private network|Virtual Private Networking]]) is used to construct and connect private networks using the public [[wikipedia:Internet|Internet]]. Communications are secured by means of some type of [[wikipedia:Encryption|encryption]], depending on the specific type of VPN. In general, there are two kinds of VPN: * ''Remote-access'', in which both payload and data are encrypted. * ''Site-to-site'', in which only data are encrypted. ==== VPN Resources ==== * '''[http://www.vpnlabs.com/ VPN Labs]''' (open community for researching, reviewing, and discussing VPN) ==== VPN Service Providers ==== * '''[http://www.anchorfree.com/hotspot-shield/ AnchorFree Hotspot Shield]''' (ad banners) * [http://www.hotspotvpn.com/ HotSpotVPN] (commercial) * [http://www.iopus.com/iPig/ iPIG] (10 MB free, commercial thereafter) * '''[http://www.jiwire.com/hotspot-helper.htm JiWire Hotspot Helper]''' (commercial) * [http://publicvpn.com/ PublicVPN.com] (commercial) * [http://vpnprivacy.com VPN Privacy] anonymous PPTP (commercial) * [http://www.witopia.net/ WiTopia] (commercial) === What Makes for a Strong Password or Passphrase? === *See ''[[Wikipedia:Password strength]]'' *See also: ** [[wikipedia:Password|Password]] ** [[wikipedia:Passphrase|Passphrase]] ** [http://world.std.com/~reinhold/diceware.html Diceware Passphrase Home Page] ** [http://passwordsafe.sourceforge.net/ Password Safe] (generates and stores passwords securely) === Wireless Isolation === * If you want to open up wireless to outsiders (even just a neighbor), look for a wirelesss router with an '''isolation''' feature that blocks wireless-to-wired networking, most often found in [[#Hotspot Routers|"hotspot" routers]]. * If you also have wireless devices, then look for a wireless router or access point with a '''wireless isolation''' feature that blocks peer-to-peer wireless networking (''e.g.,'' [http://www.netgear.com/products/details/WG302.php NETGEAR WG302]). === Guest Account === A good alternative to [[#Wireless Isolation|Wireless Isolation]] is a '''Guest Account''' feature that not only isolates wireless guests from your own wireless (and wired) networking, but also can provide security ([[wikipedia:Wi-Fi Protected Access|WPA]]) for your guests. Products with such capability include: * [http://catalog.belkin.com/IWCatProductPage.process?Product_Id=377018 Belkin N1 Vision wireless router F5D8232-4]<br>(different SSID for Private and Guests) * [http://www.myessentialssupport.com/product/?pid=ME1004-R My Essential G Router ME-1004R] (Belkin)<br>(same SSID for Private and Guests, different WPA passphrases) === What is Wardriving? === * See [[wikibooks:Wifi:Wardriving|Wifi:Wardriving]] == Wi-Fi Hotspots == * See ''[[Wi-Fi How To#Setup a hotspot|How to Setup a hotspot]]'' === Free Public HotSpot Directories === * '''USA (and other countries)''' ** [http://www.anchorfree.com/ AnchorFree] ** [http://www.jiwire.com/ JiWire] ** [http://metrofreefi.com/ MetroFreeFi] ** [http://wififreespot.com/ Wi-Fi-FreeSpot Directory] ** [http://www.wifinder.com/ WiFinder] * '''Australia''' ** [http://www.wifisearch.com.au/ Australian HotSpots] === Commercial Hotspots === * '''Directories''' ** [http://airportwifiguide.com/ AirportWiFiGuide.com] (U.S. Airports) ** [http://www.jiwire.com/ JiWire] ** [http://www.wifinder.com/ WiFinder] * '''Networks''' ** [http://www.airpath.com/ Airpath] ** [http://www.sbc.com/gen/general?pid=1080&cdvn=localize&prod-snip=freedomlink_bus at&t (SBC) FreedomLink] ** [http://www.boingo.com/ Boingo] ** [http://www.stsn.com/ iBAHN] ** [http://www.icoacorp.com/ ICOA] ** [http://www.ipass.com/ iPass] ** [http://www.nnu.com/ NetNearU] ** [http://www.sprint.com/business/products/products/sprintPCSWI-FIAccess.jsp Sprint] ** [http://hotspot.t-mobile.com/ T-Mobile] ** [http://www.wayport.com/ Wayport] ** [http://www.weroam.com/ WeRoam] == Special Wi-Fi Applications == === Marine === See ''[[Wi-Fi on a Boat]]'' === Mesh networks === Mesh is a wireless co-operative communication infrastructure between multiple individual wireless transceivers (''i.e., ''a wireless mesh) that have [[wikipedia:Internet Protocol|IP]] networking capabilities. More information: * [[wikipedia:Wireless mesh network|Wireless mesh network]] (Wikipedia) * [[w:c:newmedia:Mesh Networks|Mesh Networks]] (new media Wikia) * [http://www.locustworld.com/ LocustWorld] * [http://pdos.csail.mit.edu/roofnet/doku.php RoofNet] ** [http://meraki.net/ Meraki Networks] * [http://www.americasnetwork.com/americasnetwork/data/articlebrief/americasnetwork/412002/34898/article.pdf Rooftop Networks] (Nokia) === Streaming Audio to Home Stereo === * '''Media Adapter with computer as server:''' ** Wired Media Adapter with a Wi-Fi-Ethernet bridge/gaming adapter (''e.g.,'' [http://www.hauppauge.com/html/mediamvp_datasheet.htm Hauppauge MediaMVP] with [http://www.linksys.com/ Linksys WRT54G] as client bridge) ** Wireless Media Adapter (''e.g.,'' [http://www.apple.com/airportexpress/ Apple Airport Express] driven by [http://www.apple.com/itunes/ Apple iTunes software]) * '''Standalone Internet radio connecting to Wi-Fi network:''' ** Wired Internet radio with a Wi-Fi-Ethernet bridge/gaming adapter (''e.g.,'' [http://www.slimdevices.com/ Slim Devices Squeezebox] with [http://www.linksys.com/ Linksys WRT54G] as client bridge) ** Wireless Internet radio == Troubleshooting Wi-Fi == === Interference === * '''Checklist of possible interference sources:''' :{| | [[Image:CheckBox.gif]] || [[wikipedia:Microwave oven|Microwave oven]] |- | [[Image:CheckBox.gif]] || 2.4 Ghz video or [[wikipedia:Security camera|security camera]] link ([[wikipedia:X10 (industry standard)|X10]]). |- | [[Image:CheckBox.gif]] || Municipal [[wikipedia:Wireless|wireless]] [[wikipedia:Telecommunications network|network]]. |- | [[Image:CheckBox.gif]] || [[wikipedia:Bluetooth|Bluetooth]] devices ([[wikipedia:Mouse (computing)|mouse]], [[wikipedia:Telephone|phone]], [[wikipedia:Personal digital assistant|PDA]], [[wikipedia:Headphones|headset]], [[wikipedia:Cell phone|cell phone]], ''etc.'') |- | [[Image:CheckBox.gif]] || Portable [[wikipedia:Wireless|wireless]] [[wikipedia:TV camera|TV camera]] used at sports events. |- | [[Image:CheckBox.gif]] || [[wikipedia:Frequency-hopping|Spread spectrum Frequency hopping]] [[wikipedia:Cordless telephone|cordless phones]] (''e.g.,'' [[wikipedia:Panasonic|Panasonic]] Gigarange)<br><small>Note: 2.4 GHz phones are not an issue in the UK(Eur), as [[wikipedia:Digital Enhanced Cordless Telecommunications|DECT]] phones operate from 1.88 GHz to 1.9 GHz.</small> |- | [[Image:CheckBox.gif]] || [[wikipedia:Wi-Fi|Wi-Fi]] (IEEE 802.11b/g) wireless [[wikipedia:Computer keyboard|keyboard]], [[wikipedia:Personal digital assistant|PDA]], and/or [[wikipedia:Cell phone|cell phone]]. |- | [[Image:CheckBox.gif]] || 2.4 GHz [[wikipedia:Wireless|wireless]] [[wikipedia:Gamepad|gamepad]] and/or controller. |- | [[Image:CheckBox.gif]] || [[wikipedia:Electrodeless lamp|RF Excited Lighting]] (''e.g.,'' Fusion Lighting).<br>''See [http://www.bwianews.com/2001_11_01_archive.html Part 18 RF Lighting, A Potential "Extinction Level Event" For Communications Users Of The 2.4 GHz Band]'' |- | [[Image:CheckBox.gif]] || 2.4 GHz [[wikipedia:Wireless|wireless]] [[wikipedia:Baby monitor|baby monitor]]. |- | [[Image:CheckBox.gif]] || 2.4 GHz [[wikipedia:Amateur radio|ham radio]] operation. |- | [[Image:CheckBox.gif]] || [[wikipedia:Wisp|WISP]] (Wireless Internet Service Providers) which may be using non-[[wikipedia:Wi-Fi|Wi-Fi]] type of [[wikipedia:Modulation|modulation]] (''e.g.,'' [[wikipedia:WiMax|WiMAX]]). |- | [[Image:CheckBox.gif]] || Breezecom/Alvarion/Symbol/Raylink [[wikipedia:Frequency-hopping|spread spectrum frequency hopping]] [[wikipedia:Telecommunications network|networks]]. |- | [[Image:CheckBox.gif]] || Western Multiplex or Proxim non-[[wikipedia:Wi-Fi|Wi-Fi]] [[wikipedia:Wireless|wireless]] links (''e.g.,'' [[wikipedia:Lynx (protocol)|Lynx]]). |- | [[Image:CheckBox.gif]] || [[wikipedia:Homerf|HomeRF]] [[wikipedia:Frequency-hopping|spread spectrum frequency hopping]] [[wikipedia:Telecommunications network|network]]. |- | [[Image:CheckBox.gif]] || [[wikipedia:Zigbee|ZigBee]] [[wikipedia:IEEE 802.15|IEEE 802.15.4]] [[wikipedia:Sensor|sensor]] [[wikipedia:Wireless|wireless]] [[wikipedia:Telecommunications network|network]]. |- | [[Image:CheckBox.gif]] || [[wikipedia:Microwave|Microwave]] [[wikipedia:Drying (food)|fruit drying]] oven, plastic mold preheater. |- | [[Image:CheckBox.gif]] || [[wikipedia:Instability|Unstable]] high power [[wikipedia:Wi-Fi|Wi-Fi]] [[wikipedia:Power amplifier|power amplifier]] spewing [[wikipedia:Radio frequency|RF]] "garbage". |} * '''Resources on interference''' ** [http://www.wi-fiplanet.com/tutorials/article.php/953511 Minimizing 802.11 Interference Issues] ** [http://www.networkworld.com/columnists/2004/0816wizards.html Stop the interference!] * '''Checking for Wi-Fi networks''' ** [http://www.stumbler.net/ Network Stumbler] ** [http://www.kismetwireless.net/ Kismet] ** [http://www.kasuei.com/hitchhiker/ Hitchhiker] * '''Non-interfering Wi-Fi channels'''<br>Closely spaced Wi-Fi channels overlap, and signals on two different channels can interfere with each other, especially when they are less than 5 channels apart, with the amount of interference decreasing with increasing channel separation. (Thus channels 1 and 3 interfere less with each other than channels 1 and 2.) ''For minimum interference between different Wi-Fi networks, '''first try channels 1, 6, and 11''', which have minimal overlap.'' === Poor Signal === * See [[#Antennas|Antennas]]. === SSID Conflict === :When two networks have the same [[wikipedia:SSID|SSID]], wireless devices on one network may try to connect to the other network (because they look like the same network), which can cause problems. This can easily happen when two different networks use hardware from the same vendor with the same default SSID. ''To avoid such problems, '''configure a unique SSID''' for your network that won't conflict with other networks, now or in the future.'' === MAC Address Cloning === {{Stub}} [[Category:Wi-Fi]]

Return to Wi-Fi.