AirPort
From AudioLexic
AirPort is a local area wireless networking system from Apple Inc. based on the IEEE 802.11b standard (also known as Wi-Fi) and certified as compatible with other 802.11b devices. A later family of products based on the IEEE 802.11g specification is known as AirPort Extreme. The latest family of products is based on the draft-IEEE 802.11n specification and carries the same name.
AirPort and AirPort Extreme in common usage can refer to the protocol (802.11b and 802.11g, respectively), the expansion card or the base station.
In Japan, "AirPort" had already been registered with the I-O data device Ltd. Instead, Apple uses "AirMac".
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[edit] Overview
AirPort debuted on July 21, 1999 at the Macworld Expo in New York City with Steve Jobs picking up an iBook supposedly to give the cameraman a better shot as he surfed the Web—the applause quickly built as people realized there were no wires. The initial offering included an optional expansion card for Apple's new line of iBook notebooks, plus an AirPort Base Station. The AirPort card (a repackaged Proxim—ORiNOCO Gold Card PCMCIA adapter) was later added as an option for almost all of Apple's product line, including PowerBooks, eMacs, iMacs, and Power Macs. Only Xserves do not have an AirPort card option. The original AirPort system allowed transfer rates up to 11 Mbit/s and was commonly used to share Internet access and files between multiple computers.
On January 7, 2003, Apple introduced AirPort Extreme, based on the 802.11g specification. AirPort Extreme allows theoretical peak data transfer rates of up to 54 Mbit/s, and is fully backward-compatible with existing 802.11b wireless network cards and base stations. Several of Apple's current desktop computers and portable computers, including the MacBook Pro, MacBook, Mac mini, and iMac ship with an AirPort Extreme card as standard (as of May 2006). All other modern Macs have an expansion slot for the card. AirPort and AirPort Extreme cards are not physically compatible: AirPort Extreme cards cannot be installed in older Macs, and AirPort cards cannot be installed in newer Macs. The original AirPort card was discontinued in June 2004.
On June 7 2004, Apple released the AirPort Express Base Station as a lower-priced, more mass-market alternative to the AirPort Extreme Base Station.
On January 9 2007, Apple unveiled a new AirPort Extreme base station, now with styling similar to that of the Mac mini and Apple TV.
Although both AirPort and AirPort Extreme cards are available only for Macintosh computers, all AirPort base stations and cards are fully compatible with third-party base stations and wireless cards, so long as they conform to the 802.11a, 802.11b or 802.11g networking standards. Due to the nature of draft-n hardware, it is unlikely that the new model will interoperate with 802.11n routers from other manufacturers. However, due to the interoperability among previous models, it is not uncommon to see wireless networks composed of several types of AirPort base station serving both old and new Macintosh, Microsoft Windows, and even Linux systems. Apple's software drivers for AirPort Extreme also support some Broadcom and Atheros-based PCI Wireless adapters when fitted to PowerMac computers.
[edit] Base stations
An AirPort base station is used to connect AirPort-enabled computers to the Internet, each other, a wired LAN, and/or other devices.
[edit] AirPort
The original base station (known as Graphite) featured a modem and an Ethernet port. It was based on the same Lucent WaveLAN Bronze PC Card as the AirPort Card, and used an embedded 486 processor. It was released July 21, 1999. The Graphite AirPort Base Station is functionally identical to the Lucent RG-1000 wireless base station.
A second generation model (known as Dual Ethernet or Snow) was introduced on November 13 ,2001. It added a second Ethernet port, allowing it to share a wired network connection with both wired and wireless clients. Also new was the ability to connect to America Online's dial-up service—a feature unique to Apple base stations. This model was based on Motorola's PowerPC 860 processor.
[edit] AirPort Extreme
The AirPort Base Station was discontinued after the updated AirPort Extreme was announced on January 7, 2003. In addition to providing wireless connection speeds of up to a maximum of 54 Mbit/s, it adds an external antenna port and a USB port. The antenna port allows the addition of a signal-boosting antenna, and the USB port allows the sharing of a USB printer. A connected printer is made available via Bonjour's "zero configuration" technology and IPP to all wired and wireless clients on the network. A second model lacking the modem and external antenna port was briefly made available, but then discontinued after the launch of AirPort Express (see below). On April 19 2004, a third version, marketed as the 'AirPort Extreme Base Station (with Power over Ethernet and UL 2043), was introduced that supports Power over Ethernet and complies to the UL 2043 specifications for safe usage in air handling spaces, such as above suspended ceilings. All three models support the Wireless Distribution System (WDS) standard. The model introduced in January 2007 does not have a corresponding PoE, UL-compliant variant.
An AirPort Extreme base station can serve up to 50 wireless clients at once and thus, is more suitable for a corporate environment than the AirPort Express.
[edit] AirPort Express
The AirPort Express is a simplified and compact AirPort Extreme base station allowing only up to 10 networked users with a new feature called AirTunes. It did not replace the AirPort Extreme base station. It was introduced by Apple on June 7 2004 and includes an analog/optical audio mini-jack output, a USB port for remote printing, and a single Ethernet port.
The main processor in the AirPort Express is a Broadcom BCM4712KFB wireless networking chipset. This has a 200 MHz MIPS processor built in. The audio is handled by a Texas Instruments PCM2705 16-bit digital-to-analog converter.
The device can be used as an Ethernet-to-wireless bridge.
[edit] AirTunes
AirTunes allows an AirPort-enabled computer with the iTunes music player to simultaneously send a single stream of music to multiple (up to three) stereos connected to an AirPort Express. The AirPort Express can be used to extend the range of existing AirPort Extreme networks by using WDS-bridging, which allows AirTunes functionality (as well as internet access, file and printer sharing, etc.) to be extended across a larger distance and multiple wired and wireless clients.
Another use of the USB port is to control AirTunes using a Keyspan USB-enabled infrared remote control.
The AirPort Express's streaming media capabilities use the Apple's Remote Audio Access Protocol (RAOP), a variant of RTSP/RTP. Currently, the AirTunes system is not compatible with the Apple Remote's volume buttons. Likewise, AirTunes will not stream a video's audio. Several third-party AirPort Express clients exist to provide connectivity to an AirPort Express from sources other than iTunes. These include Airfoil for Mac OS X and Windows, JustPort for Windows, and raop-play for Linux.
[edit] AirPort Extreme (802.11n)
The AirPort Extreme was updated on January 9, 2007. It features support for 802.11a/b/g and draft-n protocols. This revision also adds two additional LAN ports for a total of three. The form-factor has changed to Apple's square-shaped design and it now more closely resembles the Apple TV and Mac Mini. The footprint is identical to the Mac Mini (6.5" sq.), however the AirPort is about half the height of the mini.
Among other additions, the USB Port now also supports connecting an external drive and using AirPort Extreme as a file server. Nicknamed AirPort Disk, this feature is compatible with Mac OS X and Microsoft Windows. The USB port also supports the connection of a USB hub, allowing both an external drive and printer to be connected at the same time.
[edit] AirPort Cards
An AirPort Card is an Apple-branded wireless card used to connect to wireless networks such as those provided by an AirPort Base Station.
[edit] AirPort 802.11b Card
The original model, known as simply AirPort Card was a re-branded Lucent WaveLAN Bronze PC Card, in a modified housing that lacked the integrated antenna. It was designed to be capable of of being user-installable.
[edit] AirPort Extreme 802.11g Cards
Corresponding with the release of the AirPort Extreme Base Station, the AirPort Extreme card became available as an option on the current models. The Extreme card is based on a Broadcom 802.11g chipset and is housed in a custom enclosure that is mechanically proprietary, but is electrically compatible with the Mini PCI standard. It was also capable of being user-installed.
A different 802.11g card was included in the last iteration of the PowerPC-based PowerBooks and iBooks. A major distinction for this card was that it was the first "combo" card that included both 802.11g as well as Bluetooth. It was also the first card that was not user-installable. It was again a custom form factor, but was still electrically a Mini PCI interface for the Broadcom WLAN chip. A separate USB connection was used for the on-board Bluetooth chip.
[edit] Integrated AirPort Extreme 802.11a/b/g and /n cards
As AirPort Extreme began to come standard on all notebook models, Apple dropped the user-installable designs (for notebooks, iMacs and Mac Minis--PowerMacs could still be updated post-purchase) completely in July, 2005 in the iBook G4 (Mid 2005). With the introduction of the Intel-based MacBook Pro in January 2006, Apple began to use a PCI Express mini card. Cards with this form factor are now used in all AirPort-equipped Macintoshes.
In early 2007, Apple announced that most Intel Core 2 Duo-based Macs, which had been shipping since October 2006, already included AirPort Extreme cards compatible with the draft-802.11n specification. 802.11n capability was unlocked by a driver included with the new draft-802.11n-capable AirPort Extreme Base Station, or by purchasing the driver separately from the Apple Store online. This card was also a PCI Express mini design, but utilized three antenna connectors in the notebooks and iMacs, in order to utilize a 2x3 MIMO antenna configuration. The cards in the Mac Pro and Apple TV have 2 antenna connectors and support a 2x2 configuration.
[edit] Security
AirPort and AirPort Extreme support a variety of security technologies to prevent eavesdropping and unauthorized network access. Cryptography plays a major role since all wireless networks are inherently vulnerable to eavesdropping, unlike wired networks which can, in most cases, be physically secured.
The original family of AirPort base stations, like most other Wi-Fi products, used 40-bit or 128-bit Wired Equivalent Privacy (WEP). AirPort Extreme and Express base stations retain this option, but also allow and encourage the use of Wi-Fi Protected Access (WPA) and, as of July 14, 2005, WPA2.
Generally, WEP is considered "broken". In March 2005, a demonstration by the FBI showed that they could crack a WEP key in 3 minutes using freely available tools from the internet, although as early as 2001 holes were being found in the WEP protocol.
In response to mounting concern over the insecurity of WEP, the WPA standard was made available in June 2003 as an intermediate solution until a more permanent and secure protocol could be developed. This new standard, known as WPA2, or IEEE 802.11i, was ratified on June 24, 2004 and uses the Advanced Encryption Standard (AES).
AirPort extreme cards, using the Broadcom chipset, have the Media Access Control layer in software. The driver is closed source.
[edit] See also
[edit] External links
- AirPort Extreme at Apple.com
- AirPort Express at Apple.com
- AirPort Support at Apple.com
- Designing AirPort Networks (PDF)
- Managing AirPort Extreme Networks (PDF)
- AirPort Base Station disassembly and benchmarks at iFixit
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