Onnowpurbo: /* See also */

2010-01-26T08:25:59Z

Onnowpurbo: New page: Planet WsAP-4000 Wireless Access Point Neteon Industrial Wireless Access Point In [[computer networ...

2010-01-24T23:59:50Z

New page: thumb|Planet WsAP-4000 Wireless Access Point thumb|Neteon Industrial Wireless Access Point In [[computer networ...

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[[Image:Planet WAP-4000.JPG|thumb|Planet WsAP-4000 Wireless Access Point]]
[[Image:Industrial wireless access point.JPG|thumb|Neteon Industrial Wireless Access Point]]
In [[computer networking]], a '''wireless access point''' (WAP) is a device that allows wireless communication devices to connect to a [[wireless network]] using [[Wi-Fi]], [[Bluetooth]] or related standards. The WAP usually connects to a [[Ethernet|wired network]], and can relay data between the wireless devices (such as computers or printers) and wired devices on the network.

Industrial grade WAPs are rugged, with a metal cover and a [[DIN rail]] mount. During operations they can tolerate a wider temperature range, high humidity and exposure to water, dust, and oil. Wireless security includes: [[WPA-PSK]], [[WPA2]], IEEE 802.1x/[[RADIUS]], [[Wireless Distribution System|WDS]], [[Wired Equivalent Privacy|WEP]], [[Temporal Key Integrity Protocol|TKIP]], and [[CCMP]] ([[Advanced Encryption Standard|AES)]] encryption. Unlike home consumer models, industrial wireless access points can also be used as a bridge, router, or a client.

== Introduction ==
[[Image:Linksys WAP54G.JPG|thumb|Linksys WAP54G 802.11g Wireless Access Point]]
[[Image:RouterBoard 112 with U.FL-RSMA pigtail and R52 miniPCI Wi-Fi card.jpg|thumb|[[Embedded system|embedded]] RouterBoard 112 with [[U.FL]]-[[SMA connector|RSMA]] pigtail and R52 [[mini PCI]] [[Wi-Fi]] card widely used by [[wireless]] [[Internet]] service providers ([[Wireless internet service provider|WISP]]s) across the world]]
Prior to [[wireless networks]], setting up a computer network in a business, home, or school often required running many cables through walls and ceilings in order to deliver network access to all of the network-enabled devices in the building. With the advent of the Wireless Access Point, network users are now able to add devices that access the network with few or no cables. Today's WAPs are built to support a standard for sending and receiving data using radio frequencies rather than cabling. Those standards, and the frequencies they use are defined by the [[IEEE]]. Most WAPs use [[IEEE 802.11]] standards.

== Common WAP Applications ==
A typical corporate use involves attaching several WAPs to a wired network and then providing wireless access to the office [[Local Area Network|LAN]]. The wireless access points are managed by a [[WLAN Controller]] which handles automatic adjustments to RF power, channels, authentication, and security. Further, controllers can be combined to form a [[wireless mobility group]] to allow inter-controller roaming. The controllers can be part of a mobility domain to allow clients access throughout large or regional office locations. This saves the clients time and administrators overhead because it can automatically re-associate or re-authenticate. Further, multiple controllers and all of the hundreds of access points attached to those controllers can be managed by a software called [[Cisco Wireless Control System]] Which handles the same functions as a controller yet adds the bonus features of mapping user or RFID locations to an uploaded map, upgrading controllers and access point firmware, and rogue detection/handling. In this instance, the WAP functions as a [[wireless gateway]] for clients to access the wired network.

A [[Hotspot (Wi-Fi)|Hot Spot]] is a common public application of WAPs, where wireless clients can connect to the Internet without regard for the particular networks to which they have attached for the moment. The concept has become common in large cities, where a combination of coffeehouses, libraries, as well as privately owned open access points, allow clients to stay more or less continuously connected to the Internet, while moving around. A collection of connected Hot Spots can be referred to as a lily-pad network.

The majority of WAPs are used in [[Home network|Home wireless networks]]. Home networks generally have only one WAP to connect all the computers in a home. Most are [[wireless router]]s, meaning [[converged device]]s that include the WAP, a [[router]], and, often, an [[ethernet switch]]. Many also include a broadband modem. In places where most homes have their own WAP within range of the neighbors' WAP, it's possible for technically savvy people to turn off their encryption and set up a [[wireless community network]], creating an intra-city communication network without the need of wired networks.

A WAP may also act as the network's arbitrator, negotiating when each nearby client device can transmit. However, the vast majority of currently installed [[IEEE 802.11]] networks do not implement this, using a distributed pseudo-random algorithm called [[Carrier sense multiple access|CSMA/CA]] instead.

== Wireless Access Point vs. Ad-Hoc Network ==

Some people confuse Wireless Access Points with [[Wireless ad hoc network|Wireless Ad-Hoc networks]]. An Ad-Hoc network uses a connection between two or more devices without using a wireless access point: the devices communicate directly when in range. An Ad-Hoc network is used in situations such as a quick data exchange or a multiplayer LAN game because setup is easy and does not require an access point. Due to its peer-to-peer layout, Ad-Hoc connections are similar to [[Bluetooth]] ones and are generally not recommended for a permanent installation.

[[Internet access]] via [[ad-hoc network|Ad-Hoc networks]], using features like Windows' [[Internet Connection Sharing]], may work well with a small number of devices that are close to each other, but Ad-Hoc networks don't scale well. Internet traffic will converge to the nodes with direct internet connection, potentially congesting these nodes. For internet-enabled nodes, Access Points have a clear advantage, being designed to handle this load.

== Limitations ==
One [[IEEE 802.11]] WAP can typically communicate with 30 client systems located within a [[radius]] of 100 m. However, the actual range of communication can vary significantly, depending on such variables as indoor or outdoor placement, height above ground, nearby obstructions, other electronic devices that might actively interfere with the signal by broadcasting on the same frequency, type of [[antenna (electronics)|antenna]], the current weather, operating [[radio frequency]], and the power output of devices. Network designers can extend the range of WAPs through the use of [[repeater]]s and [[Passive repeater|reflector]]s, which can bounce or [[Amplifier|amplify]] radio signals that ordinarily would go un-received. In experimental conditions, wireless networking has operated over distances of several [[kilometer]]s.

Most jurisdictions have only a [[IEEE 802.11#Channels and international compatibility|limited number of frequencies]] legally available for use by wireless networks. Usually, adjacent WAPs will use different frequencies (Channels) to communicate with their clients in order to avoid [[Interference (communication)|interference]] between the two nearby systems. Wireless devices can "listen" for data traffic on other frequencies, and can rapidly switch from one frequency to another to achieve better reception. However, the limited number of frequencies becomes problematic in crowded downtown areas with tall buildings using multiple WAPs. In such an environment, signal overlap becomes an issue causing interference, which results in signal dropage and data errors.

Wireless networking lags behind wired networking in terms of increasing [[Bandwidth (computing)|bandwidth]] and [[throughput]]. While (as of 2004) typical wireless devices for the consumer market can reach speeds of 11 Mbit/s ([[megabit]]s per second) ([[Institute of Electrical and Electronics Engineers|IEEE]] [[802.11b]]) or 54 Mbit/s ([[IEEE]] [[802.11a]], [[IEEE]] [[802.11g]]), wired hardware of similar cost reaches 1000 Mbit/s ([[Gigabit Ethernet]]). One impediment to increasing the speed of wireless communications comes from [[Wi-Fi]]'s use of a shared communications medium, so a WAP is only able to use somewhat less than half the actual over-the-air rate for data throughput. Thus a typical 54 MBit/s wireless connection actually carries [[TCP/IP]] data at 20 to 25 Mbit/s. Users of legacy wired networks expect faster speeds, and people using wireless connections keenly want to see the wireless networks catch up.

As of 2007 a new standard for wireless, [[802.11n]] is awaiting final certification from IEEE. This new standard operates at speeds up to 540 Mbit/s and at longer distances (~50 m) than 802.11g. Use of legacy wired networks (especially in consumer applications) is expected to decline sharply as the common 100 Mbit/s speed is surpassed and users no longer need to worry about running wires to attain high bandwidth.

By the year 2008 ''draft'' 802.11n based access points and client devices have already taken a fair share of the market place but with inherent problems integrating products from different vendors.

== Security ==
Wireless access has special [[security]] considerations. Many wired networks base the security on physical access control, trusting all the users on the local network, but if wireless access points are connected to the network, anyone on the street or in the neighboring office could connect.

The most common solution is wireless traffic encryption. Modern access points come with built-in encryption. The first generation encryption scheme [[Wired Equivalent Privacy|WEP]] proved easy to crack; the second and third generation schemes, [[Wi-Fi Protected Access|WPA]] and [[IEEE 802.11i|WPA2]], are considered secure if a strong enough [[password]] or [[passphrase]] is used.

Some WAPs support hotspot style authentication using [[RADIUS]] and other [[authentication server]]s.

== See also ==
* [[Hotspot (Wi-Fi)|Hotspots]] - access points or wireless networks open to the public
* [[Wireless LAN]] - networks consisting of zero or more access points plus devices
* [[Wireless bridge]] - between networks sharing same Service Set Identifier (SSID) and radio channel
* [[Wi-Fi Array]] System of multiple APs
* [[LWAPP]] - Lightweight Access Point Protocol used to manage a large set of WAPs
* [[WarXing]] - searching for open networks
* [[Femtocell]] - a local-area [[base station]] using [[cellular network]] standards such as [[UMTS]], rather than [[Wi-Fi]]
* [[WiMAX]] - wide-area wireless standard that has a few elements in common with Wi-Fi

@@ Line 46: / Line 46: @@
 * [[Hotspot (Wi-Fi)|Hotspots]] - access points or wireless networks open to the public
 * [[Wireless LAN]] - networks consisting of zero or more access points plus devices
-* [[Wireless bridge]] - between networks sharing same Service Set Identifier (SSID) and radio channel
+* [[Wireless bridge]] - between networks sharing same [[Service Set Identifier]] ([[SSID]]) and radio channel
 * [[Wi-Fi Array]] System of multiple APs
 * [[LWAPP]] - Lightweight Access Point Protocol used to manage a large set of WAPs
 * [[WarXing]] - searching for open networks
 * [[Femtocell]] - a local-area [[base station]] using [[cellular network]] standards such as [[UMTS]], rather than [[Wi-Fi]]
-* [[WiMAX]] - wide-area wireless standard that has a few elements in common with Wi-Fi
+* [[WiMAX]] - wide-area wireless standard that has a few elements in common with [[Wi-Fi]]

Access Point - Revision history

Onnowpurbo: /* See also */

Onnowpurbo: New page: Planet WsAP-4000 Wireless Access Point Neteon Industrial Wireless Access Point In [[computer networ...