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23 janvier 2011 7 23 /01 /janvier /2011 08:38

Wi-Fi is a trademark of the Wi-Fi Alliance. A Wi-Fi enabled device such as a personal computer, video game console, smartphone or digital audio player can connect to the Internet when within range of a wireless network connected to the Internet  (Dell XPS M1210 Batteryhttp://www.hdd-shop.co.uk .

The coverage of one or more (interconnected) access points — called hotspots — generally comprises an area the size of a few rooms but may be expanded to cover many square miles, depending on the number of access points with overlapping coverage  (Dell Studio XPS 1340 Battery)         .

'Wi-Fi' is not a technical term. However, the Alliance has generally enforced its use to describe only a narrow range of connectivity technologies includingwireless local area network (WLAN) based on the IEEE 802.11 standards, device to device connectivity [such as Wi-Fi Peer to Peer AKA Wi-Fi Direct], and a range of technologies that support PAN, LAN and even WAN connections  (Dell Studio XPS 1640 Battery)     .

Derivative terms, such as Super Wi-Fi, coined by the U.S. Federal Communications Commission (FCC) to describe proposed networking in the former UHF TV band in the US, may or may not be sanctioned by the alliance.As of November 2010 this was very unclear (Dell Vostro 1710 Battery)      .

The technical term "IEEE 802.11" has been used interchangeably with Wi-Fi, but over the past few years Wi-Fi has become a superset of IEEE 802.11. Wi-Fi is used by over 700 million people, there are over 750,000 hotspots (places with Wi-Fi Internet connectivity) around the world, and about 800 million new Wi-Fi devices every year  (Dell KM958 battery)       .

Wi-Fi products that complete the Wi-Fi Alliance interoperability certification testing successfully can use the Wi-Fi CERTIFIED designation and trademark.

Not every Wi-Fi device is submitted for certification to the Wi-Fi Alliance        (Sony VGP-BPS13 battery)        .

The lack of Wi-Fi certification does not necessarily imply a device is incompatible with Wi-Fi devices/protocols. If it is compliant or partly compatible, the Wi-Fi Alliance may not object to its description as a Wi-Fi device though technically only the CERTIFIED designation carries their approval         (Sony VGP-BPS13/B battery)        .

Wi-Fi certified and compliant devices are installed in many personal computers, video game consoles, MP3 players, smartphones, printers, digital cameras, and laptop computers.

This article focuses on the certification and approvals process and the general growth of wireless networking under the protocols certified by the Wi-Fi Alliance        (Sony VGP-BPS13/S battery)             .

For more on the technologies, see the appropriate articles with IEEE, ANSI, IETF, W3 and ITU prefixes (acronyms for the accredited standards organizations that have created formal technology standards for the protocols by which devices communicate). Non-Wi-Fi-Alliance wireless technologies intended for fixed points such as Motorola Canopy are usually described as fixed wireless  (Sony VGP-BPS13A/B battery)       .

Non-Wi-Fi-Alliance wireless technologies intended for mobile use are usually described as 3G, 4G or 5G, reflecting their origins and promotion by telephone or cellphone companies.

Wi-Fi certification

Wi-Fi technology builds on IEEE 802.11 standards      (Sony VGP-BPS13B/B battery)         .

The IEEE develops and publishes some of these standards, but does not test equipment for compliance with them. The non-profit Wi-Fi Alliance formed in 1999 to fill this void — to establish and enforce standards for interoperability and backward compatibility, and to promote wireless local-area-network technology       (Sony VGP-BPL9 battery)         .

As of 2010 the Wi-Fi Alliance consisted of more than 375 companies from around the world. Manufacturers with membership in the Wi-Fi Alliance, whose products pass the certification process, gain the right to mark those products with the Wi-Fi logo  (Sony VGP-BPS13B/B battery)   .

Specifically, the certification process requires conformance to the IEEE 802.11 radio standards, the WPA and WPA2 security standards, and the EAP authentication standard. Certification may optionally include tests of IEEE 802.11 draft standards  Sony VGP-BPL15 battery ,

interaction with cellular-phone technology in converged devices, and features relating to security set-up, multimedia, and power-saving.

Most recently, a new security standard, Wi-Fi Protected Setup, allows embedded devices with limited graphical user interface to connect to the Internet with ease    Dell Inspiron E1505 battery .

Wi-Fi Protected Setup has 2 configurations: The Push Button configuration and the PIN configuration. These embedded devices are also called The Internet of Things and are low-power, battery-operated embedded systems. A number of Wi-Fi manufacturers design chips and modules for embedded Wi-Fi, such as GainSpan   Dell Latitude E6400 battery .

The name Wi-Fi

The term Wi-Fi suggests Wireless Fidelity, resembling the long-established audio-equipment classification term high fidelity (in use since the 1930s ) or Hi-Fi(used since 1950 ). Even the Wi-Fi Alliance itself has often used the phrase Wireless Fidelity in its press releases and documents        HP Pavilion dv6000 Battery ;

the term also appears in a white paper on Wi-Fi from ITAA. However, based on Phil Belanger's statement, the term Wi-Fi was never supposed to mean anything at all.

The term Wi-Fi, first used commercially in August 1999        SONY VAIO VGN-FZ Battery ,

was coined by a brand-consulting firm called Interbrand Corporation that the Alliance had hired to determine a name that was "a little catchier than 'IEEE 802.11b Direct Sequence'". Belanger also stated that Interbrand invented Wi-Fi as a play on words with Hi-Fi, and also created the yin-yang-style Wi-Fi logo     SONY VAIO VGN-FZ18 Battery .

The Wi-Fi Alliance initially used an advertising slogan for Wi-Fi, "The Standard for Wireless Fidelity", but later removed the phrase from their marketing. Despite this, some documents from the Alliance dated 2003 and 2004 still contain the term Wireless Fidelity.There was no official statement related to the dropping of the term     SONY VAIO VGN-FZ180E Battery .

The yin-yang logo indicates the certification of a product for interoperability.

Uses

Internet access

A Wi-Fi enabled device such as a personal computer, video game console, smartphone or digital audio player can connect to the Internet when within range of a wireless network connected to the Internet      SONY VAIO VGN-FZ220E Battery .

The coverage of one or more (interconnected) access points — called hotspots — can comprise an area as small as a few rooms or as large as many square miles. Coverage in the larger area may depend on a group of access points with overlapping coverage. Wi-Fi technology has been used in wireless mesh networks, for example, in London, UK      SONY VAIO VGN-FZ340E Battery .

In addition to private use in homes and offices, Wi-Fi can provide public access at Wi-Fi hotspots provided either free-of-charge or to subscribers to various commercial services. Organizations and businesses - such as those running airports, hotels and restaurants - often provide free-use hotspots to attract or assist clients      SONY VAIO VGN-FZ430E Battery .

Enthusiasts or authorities who wish to provide services or even to promote business in selected areas sometimes provide free Wi-Fi access. As of 2008 more than 300 metropolitan-wide Wi-Fi (Muni-Fi) projects had started. As of 2010 the Czech Republic had 1150 Wi-Fi based wireless Internet service providers     SONY VAIO VGN-FZ460E Battery .

Routers that incorporate a digital subscriber line modem or a cable modem and a Wi-Fi access point, often set up in homes and other premises, can provide Internet access and internetworking to all devices connected (wirelessly or by cable) to them  SONY VAIO VGN-FZ480E Battery .

With the emergence of MiFi and WiBro (a portable Wi-Fi router) people can easily create their own Wi-Fi hotspots that connect to Internet via cellular networks. Now iPhone, Android or Symbian phones can create wireless connections.

One can also connect Wi-Fi devices in ad-hoc mode for client-to-client connections without a router  SONY VAIO VGN-FZ4000 Battery .

Wi-Fi also connects places that would traditionally not have network access, for example kitchens and garden sheds.

City-wide Wi-Fi

In the early 2000s, many cities around the world announced plans for city-wide Wi-Fi networks   SONY VAIO VGN-FZ31E Battery .

This proved to be much more difficult than their promoters initially envisioned with the result that most of these projects were either canceled or placed on indefinite hold. A few were successful, for example in 2005,Sunnyvale, California became the first city in the United States to offer city-wide free Wi-Fi  SONY VAIO VGN-FZ31B Battery ,

and Minneapolis has generated $1.2 million profit annually for their provider.

In May, 2010, London, UK Mayor Boris Johnson pledged London-wide Wi-Fi by 2012. Both the City of London, UK and Islingtonalready have extensive outdoor Wi-Fi coverage   SONY VAIO VGN-FZ31J Battery .

Campus-wide Wi-Fi

Carnegie Mellon University built the first wireless Internet network in the world at their Pittsburgh campus in 1994, long before Wi-Fi branding originated in 1999. Many traditional college campuses provide at least partial wireless Wi-Fi Internet coverage  SONY VAIO VGN-FZ31M Battery .

Drexel University in Philadelphia made history by becoming the United State's first major university to offer completely wireless Internet access across the entire campus in 2000.

Direct computer-to-computer communications

Wi-Fi also allows communications directly from one computer to another without the involvement of an access point  SONY VAIO VGN-FZ31Z Battery .

This is called the ad-hoc mode of Wi-Fi transmission. This wireless ad-hoc network mode has proven popular with multiplayer handheld game consoles, such as the Nintendo DS, digital cameras, and other consumer electronics devices.

Similarly, the Wi-Fi Alliance promotes a specification called Wi-Fi Direct for file transfers and media sharing through a new discovery- and security-methodology   SONY VAIO VGN-FZ38M Battery .

Wi-Fi Direct launched in October 2010.

Future directions

As of 2010 Wi-Fi technology has spread widely within business and industrial sites. In business environments, just like other environments, increasing the number of Wi-Fi access points provides network redundancy, support for fast roaming and increased overall network-capacity by using more channels or by defining smaller cells  SONY VGP-BPS8 Battery .

Wi-Fi enables wireless voice-applications (VoWLAN or WVOIP). Over the years, Wi-Fi implementations have moved toward "thin" access points, with more of the network intelligence housed in a centralized network appliance, relegating individual access points to the role of "dumb" transceivers. Outdoor applications may utilize mesh topologies      SONY VGP-BPS13 Battery .

Operational advantages

Wi-Fi allows the deployment of local area networks (LANs) without wires for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs     SONY VGP-BPS13/S Battery .

As of 2010 manufacturers are building wireless network adapters into most laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in even more devices. Wi-Fi has become widespread in corporate infrastructures        SONY VGP-BPS13A/B Battery .

Different competitive brands of access points and client network-interfaces can inter-operate at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards compatible. "Wi-Fi" designates a globally operative set of standards: unlike mobile phones, any standard Wi-Fi device will work anywhere in the world   SONY VGP-BPS13B/B Battery .

Wi-Fi operates in more than 220,000 public hotspots and in tens of millions of homes and corporate and university campuses worldwide. The current version of Wi-Fi Protected Access encryption (WPA2) as of 2010 is considered secure, provided users employ a strong passphrase      SONY VGP-BPS13A/S Battery .

New protocols for quality-of-service (WMM) make Wi-Fi more suitable for latency-sensitive applications (such as voice and video); and power saving mechanisms (WMM Power Save) improve battery operation.

Limitations

Spectrum assignments and operational limitations are not consistent worldwide     SONY VGP-BPS13AS Battery :

most of Europe allows for an additional two channels beyond those permitted in the U.S. for the 2.4 GHz band (1–13 vs. 1–11), while Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect.

A Wi-Fi signal occupies five channels in the 2.4 GHz band            Dell Inspiron 1320n Battery ;

any two channels whose channel numbers differ by five or more, such as 2 and 7, do not overlap. The oft-repeated adage that channels 1, 6, and 11 are the only non-overlapping channels is, therefore, not accurate; channels 1, 6, and 11 do, however, comprise the only group of three non-overlapping channels in the U.S         Dell Inspiron 1464 Battery .

Equivalent isotropically radiated power (EIRP) in the EU is limited to 20 dBm (100 mW).

The current 'fastest' norm 802.11n uses double the radio spectrum compared to 802.11a or 802.11g. This means there can only be one 802.11n network on 2.4 GHz band without interference to other WLAN traffic, or none, if there already is an AP on any of the mid channels      Dell Inspiron 1564 Battery .

The on-coming 802.11ac will jam all the current WLAN bands, if allowed on same bands. There might be a chance the 802.11ac would be allocated a new band, perhaps on UHF TV white space.

Reach

Wi-Fi networks have limited range        Dell Inspiron 1764 Battery .

A typical wireless router using 802.11b or 802.11g with a stock antenna might have a range of 32 m (120 ft) indoors and 95 m (300 ft) outdoors. The IEEE 802.11nhowever, can exceed that range by more than two times. Range also varies with frequency band. Wi-Fi in the 2.4 GHz frequency block has slightly better range than Wi-Fi in the 5 GHz frequency block  Dell Studio 1450 Battery .

Outdoor ranges - through use of directional antennas - can be improved with antennas located several kilometres or more from their base. In general, the maximum amount of power that a Wi-Fi device can transmit is limited by local regulations, such as FCC Part 15in USA         Dell Studio 1457 Battery .

Due to reach requirements for wireless LAN applications, Wi-Fi has fairly high power consumption compared to some other standards. Technologies such as Bluetooth (designed to support wirelessPAN applications) provide a much shorter propagation range of <10m and so in general have a lower power consumption     Dell Latitude D610 Battery .

Other low-power technologies such as ZigBee have fairly long range, but much lower data rate. The high power consumption of Wi-Fi makes battery life in mobile devices a concern.

Researchers have developed a number of "no new wires" technologies to provide alternatives to Wi-Fi for applications in which Wi-Fi's indoor range is not adequate and where installing new wires (such as CAT-5) is not possible or cost-effective  Toshiba NB100 Battery .

For example, the ITU-T G.hn standard for high speed Local area networks uses existing home wiring (coaxial cables, phone lines and power lines). AlthoughG.hn does not provide some of the advantages of Wi-Fi (such as mobility or outdoor use), it's designed for applications (such as IPTV distribution) where indoor range is more important than mobility  Toshiba Satellite M65 battery .

Due to the complex nature of radio propagation at typical Wi-Fi frequencies, particularly the effects of signal reflection off trees and buildings, algorithms can only approximately predict Wi-Fi signal strength for any given area in relation to a transmitter  Toshiba Satellite M60 battery .

This effect does not apply equally to long-range Wi-Fi, since longer links typically operate from towers that broadcast above the surrounding foliage.

Mobility

The very limited practical range of Wi-Fi essentially confines mobile use to such applications as inventory-taking machines in warehouses or in retail spaces        Dell Latitude D830 Battery ,

barcode-reading devices at check-out stands, or receiving/shipping stations. Mobile use of Wi-Fi over wider ranges is limited, for instance, to uses such as in an automobile moving from one hotspot to another (known as Wardriving). Other wireless technologies are more suitable as illustrated in the graphic   Dell Latitude D620 Battery .

Data security risks

The most common wireless encryption-standard, Wired Equivalent Privacy (WEP), has been shown to be easily breakable even when correctly configured.Wi-Fi Protected Access (WPA and WPA2) encryption, which became available in devices in 2003, aimed to solve this problem       Dell Inspiron Mini 10 Battery .

Wi-Fi access points typically default to an encryption-free (open) mode. Novice users benefit from a zero-configuration device that works out-of-the-box, but this default does not enable anywireless security, providing open wireless access to a LAN. To turn security on requires the user to configure the device, usually via a software graphical user interface (GUI)  Sony VGN-FW11S Battery .

On unencrypted Wi-Fi networks connecting devices can monitor and record data (including personal information), but such networks may use other means of protection, such as a VPN or secure Hypertext Transfer Protocol (HTTPS) over Transport Layer Security     Sony VGN-FW11M Battery .

Population

Many 2.4 GHz 802.11b and 802.11g access-points default to the same channel on initial startup, contributing to congestion on certain channels. To change the channel of operation for an access point requires the user to configure the device  Sony VGN-FW139E/H battery .

Yet, regular users selecting a "free" channel usually leads to even worse congestion, due to the overlapping channel system. Observations during the year 2010 have shown pretty acceptable spreading of by far most of the devices being on one of the "good" channels: 1, 6 or 11          Dell Latitude E5400 Battery .

Channel pollution

Market forces may drive a process of standardization. Interoperability issues between non-Wi-Fi brands or proprietary deviations from the standard can still disrupt connections or lower throughput speeds on all devices within range, including any non-Wi-Fi or proprietary product      Dell Latitude E4200 Battery .

Moreover, the usage of the ISM band in the 2.45 GHz range is also common to Bluetooth, WPAN-CSS, ZigBee, and any new system will take its share.

Wi-Fi pollution, or an excessive number of access points in the area, especially on the neighboring channel, can prevent access and interfere with other devices' use of other access points, caused by overlapping channels in the 802.11g/b spectrum Dell Inspiron 300M Battery ,

as well as with decreased signal-to-noise ratio (SNR) between access points. This can become a problem in high-density areas, such as large apartment complexes or office buildings with many Wi-Fi access points. Additionally, other devices use the 2.4 GHz band  Dell Vostro A840 Battery :

microwave ovens, security cameras, ZigBee devices, Bluetooth devices and (in some countries) Amateur radio, video senders, cordless phones and baby monitors, all of which can cause significant additional interference. It is also an issue when municipalitiesor other large entities (such as universities) seek to provide large area coverage  Dell Studio 1737 battery .

Hardware

Standard devices

A wireless access point (WAP) connects a group of wireless devices to an adjacent wired LAN  Dell Inspiron E1505 battery .

An access point resembles a network hub, relaying databetween connected wireless devices in addition to a (usually) single connected wired device, most often an ethernet hub or switch, allowing wireless devices to communicate with other wired devices.

Wireless adapters allow devices to connect to a wireless network     Dell RM791 battery .

These adapters connect to devices using various external or internal interconnects such as PCI, miniPCI, USB, ExpressCard, Cardbus and PC Card. As of 2010, most newer laptop computers come equipped with internal adapters. Internal cards are generally more difficult to install     Dell XPS M1530 battery .

Wireless routers integrate a Wireless Access Point, ethernet switch, and internal router firmware application that provides IP routing, NAT, and DNSforwarding through an integrated WAN-interface. A wireless router allows wired and wireless ethernet LAN devices to connect to a (usually) single WAN device such as a cable modem or a DSL modem  Dell XPS M2010 battery .

A wireless router allows all three devices, mainly the access point and router, to be configured through one central utility. This utility is usually an integrated web server that is accessible to wired and wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple's AirPort  Acer Aspire One battery .

Wireless network bridges connect a wired network to a wireless network. A bridge differs from an access point: an access point connects wireless devices to a wired network at the data-link layer. Two wireless bridges may be used to connect two wired networks over a wireless link, useful in situations where a wired connection may be unavailable, such as between two separate homes  Toshiba Satellite P10 Battery .

Wireless range-extenders or wireless repeaters can extend the range of an existing wireless network. Strategically placed range-extenders can elongate a signal area or allow for the signal area to reach around barriers such as those pertaining in L-shaped corridors       SONY VGN-FZ210CE Battery .

Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a wireless device connected to any of the repeaters in the chain will have a throughput limited by the "weakest link" between the two nodes in the chain from which the connection originates to where the connection ends   Dell Precision M70 Battery .

Distance records

Distance records (using non-standard devices) include 382 km (237 mi) in June 2007, held by Ermanno Pietrosemoli and EsLaRed of Venezuela, transferring about 3 MB of data between the mountain-tops of El Águila and Platillon       Toshiba Satellite L305 Battery .

The Swedish Space Agency transferred data 420 km (260 mi), using 6 watt amplifiers to reach an overhead stratospheric balloon.

Embedded systems

Increasingly in the last few years (particularly as of 2007), embedded Wi-Fi modules have become available that incorporate a real-time operating system and provide a simple means of wirelessly enabling any device which has and communicates via a serial port  Toshiba Satellite T4900 Battery .

This allows the design of simple monitoring devices. An example is a portable ECG device monitoring a patient at home. This Wi-Fi-enabled device can communicate via the Internet.

These Wi-Fi modules are designed  so that implementers need only minimal Wi-Fi knowledge to provide Wi-Fi connectivity for their products     Toshiba PA3399U-2BRS battery .

Network security

The main issue with wireless network security is its simplified access to the network compared to traditional wired networks such as ethernet.With wired networking one must either gain access to a building (physically connecting into the internal network) or break through an external firewall       Toshiba Satellite A200 Battery .

Most business networks protect sensitive data and systems by attempting to disallow external access. Enabling wireless connectivity provides an attack vector, particularly if the network uses inadequate or no encryption.

An attacker who has gained access to a Wi-Fi network router can initiate a DNS spoofing attack against any other user of the network by forging a response before the queried DNS server has a chance to reply        Toshiba Satellite 1200 Battery .

Securing methods

A common but unproductive measure to deter unauthorized users involves suppressing the access point's SSID broadcast. This is ineffective as a security method because the SSID is broadcast in the clear in response to a client SSID query  Toshiba Satellite M300 Battery .

Another unproductive method is to only allow computers with knownMAC addresses to join the network. But intruders can defeat this method because they can often (though not always) set MAC addresses with minimal effort (MAC spoofing). If eavesdroppers have the ability to change their MAC address, then they may join the network by spoofing an authorized address  Sony Vaio PCG-5G2L Battery .

Wired Equivalent Privacy (WEP) encryption was designed to protect against casual snooping, but is now deprecated. Tools such as AirSnort or Aircrack-ng can quickly recover WEP encryption keys. Once it has seen 5-10 million encrypted packets, AirSnort can determine the encryption password in under a second  Sony Vaio PCG-5G3L Battery ;

newer tools such as aircrack-ptw can use Klein's attack to crack a WEP key with a 50% success rate using only 40,000 packets.

To counteract this in 2002, the Wi-Fi Alliance approved Wi-Fi Protected Access (WPA) which uses TKIP as a stopgap solution for legacy equipment       Sony Vaio PCG-5J1L Battery .

Though more secure than WEP, it has outlived its designed lifetime and has known attack vectors.

In 2004, the IEEE ratified the full IEEE 802.11i (WPA2) encryption standards. If used with a 802.1X server or in pre-shared key mode with a strong and uncommon passphrase WPA2 is still considered secure by many IT professionals  Sony Vaio PCG-5K2L Battery .

Piggybacking

Piggybacking refers to access to a wireless Internet connection by bringing one's own computer within the range of another's wireless connection, and using that service without the subscriber's explicit permission or knowledge      Sony Vaio PCG-5J2L Battery .

During the early popular adoption of 802.11, providing open access points for anyone within range to use was encouraged to cultivate wireless community networks, particularly since people on average use only a fraction of their downstream bandwidth at any given time     Sony Vaio PCG-5K1L Battery .

Recreational logging and mapping of other people's access points has become known as wardriving. Indeed, many access points are intentionally installed without security turned on so that they can be used as a free service. Providing access to one's Internet connection in this fashion may breach the Terms of Service or contract with the ISP  Sony Vaio PCG-5L1L Battery .

These activities do not result in sanctions in most jurisdictions; however, legislation and case law differ considerably across the world. A proposal to leave graffiti describing available services was called warchalking.A Florida court case determined that owner laziness was not to be a valid excuse   Sony Vaio PCG-6S2L Battery .

Piggybacking often occurs unintentionally, most access points are configured without encryption by default, and operating systems can be configured to connect automatically to any available wireless network. A user who happens to start up a laptop in the vicinity of an access point may find the computer has joined the network without any visible indication   Sony Vaio PCG-6S3L Battery .

Moreover, a user intending to join one network may instead end up on another one if the latter has a stronger signal. In combination with automatic discovery of other network resources (see DHCP and Zeroconf) this could possibly lead wireless users to send sensitive data to the wrong middle-man when seeking a destination (see Man-in-the-middle attack)  Sony Vaio PCG-6V1L Battery .

For example, a user could inadvertently use an insecure network to log in to awebsite, thereby making the login credentials available to anyone listening, if the website uses an insecure protocol such as HTTP.

Overview

The San Francisco Digital Inclusion Strategy (SFDIS) is a policy initiative in San Francisco, CA   Sony Vaio PCG-6W1L Battery .

It is part of TechConnect, which is an initiative aimed at achieving Mayor Gavin Newsom's campaign promise to provide all San Franciscans with free wireless internet access.

TechConnect did not originally have a digital inclusion component       Sony Vaio PCG-6W2L Battery .

After significant criticism from groups that had advanced the idea of citywide wireless, the City's Department of Telecommunications and Information Services (DTIS) created a Digital Inclusion Task Force. This Task Force created what is now apparently known as the San Francisco Digital Inclusion Strategy hopes to ease the Digital Divide in the city of San Francisco   Sony Vaio PCG-6W3L Battery .

The digital divide is the gap between those with regular, effective access to digital technologies and those without.

On the city’s website Newsom said, “We are committed to bring universal, affordable wireless broadband internet access to all San Francisco’s residents and businesses       Sony Vaio PCG-7111L Battery .”

The initiative will focus on underserved neighborhoods and disadvantaged residents within San Francisco. By applying national statistics to the city’s deomographics, they estimate that 200,000 San Francisco residents lack access to informational technology  Sony Vaio PCG-7112L Battery .

Today, the Internet and other digital technologies, are very important for employment, information/education, and social networking. Those without access to such technologies are at a distinct disadvantage.

There are six major aspects of the plan   Sony Vaio PCG-7113L Battery .

The most widely publicized is the San Francisco Municipal Wireless initiative that was the cornerstone, and originally the only component of TechConnect.

Strategic elements

According to the San Francisco Digital Inclusion Strategy Executive Summary        Sony Vaio PCG-7133L Battery ,

the six major program goals are Free and Affordable Wireless Internet Access, Computer Ownership and Basic Training Programs, Online Safety and Responsibility, Accessible Solutions, Enhanced Digital Literacy Programs, and Relevant, Multi-language Internet Content and Online Services        Sony Vaio PCG-7Z2L Battery .

Free and Affordable Wireless Internet Access

The goal is to have wireless access throughout the City- in schools, homes, and businesses and on the street. Because technology hasn’t advanced too far past the wireless routers we all use in our apartments, the wireless network will consist of maybe a thousand points of connectivity to blanket the city        Sony Vaio PCG-8Y1L Battery .

In addition to a range of low cost, high bandwidth services, the San Francisco program will offer a free basic service designed to read e-mail and surf the Internet.

The free connection will allow web access at 300 kbit/s while high-speed access (1 Mbit/s) will be available for $21.95. 3200 high-speed accounts will be available for qualifying low-income residents for $12.95    Sony Vaio PCG-8Y2L Battery .

Computer Ownership and Basic Training Programs

This program will attempt to expand personal computer ownership to all residents of San Francisco and teach users basic skills like email and web browsing to use their new tools   Sony Vaio PCG-8Z1L Battery .

The city plans to increase awareness about current programs that collect, refurbish and distribute used computers to underserved communities. In addition, a low or no-interest computer purchase program will relieve qualifying low-income residents of some of the financial stress of purchasing a new computer       Dell Studio 1555 battery .

Furthermore, technology fairs in the underserved neighborhoods will promote these services.

Online Safety and Responsibility

With the goal that all San Franciscans should feel comfortable using the Internet in ways that are appropriate to their and their families’ needs, educational programs will be implemented to increase parents’ awareness of resources that help protect children’s online safety          Sony Vaio PCG-8Z2L Battery .

Accessible Solutions

The goal behind this provision is that all San Franciscans, including those with disabilities, will have unhindered access to the Internet. People with physical and mental disabilities and some seniors may need special accommodations to more easily use a computer and the Internet         Sony VAIO PCG-5G2L Battery .

The city will promote current Accessibility and Ease of Use tools in current software. In addition, promotion of new technologies to help users with a number of disabilities will also be important.

The implementation of computer purchase programs will include at least one configuration for physical impairments  Sony VAIO PCG-5G3L Battery .

Enhanced Digital Literacy Programs

Computer training will be available for residents to move from novice to expert users. Basic technical support (over phone and on-site) and computer training will be available to underserved communities in SF       Sony VAIO PCG-5J1L Battery .

Relevant, Multi-language Internet Content and Online Services

In order to better serve San Francisco’s diverse and multicultural communities, the city hopes to increase multi-lingual and multi-cultural content geared towards underserved communities         Sony VAIO PCG-5K2L Battery .

A ‘digital inclusion’ portal will provide info about the purchasing programs and services described before. It will at least be in English, Spanish and Chinese. Community based websites and local content and news will be encouraged and promoted through Google and Earthlink           Sony VAIO PCG-5J2L Battery .

Finally, training programs will be available for communities to develop their own content.

Objections to the SFDIS

While most will agree that the goal of easing the digital divide is a good one, many informed people have raised objections to franchise contract with EarthLink/Google     Sony VAIO PCG-5K1L Battery .

Lack of ownership

Under the current model, the city and its residents will not own the infrastructure that makes free wi-fi possible. It will belong to EarthLink, who will then sell wholesale network capacity to Google      Sony VAIO PCG-5L1L Battery

Coverage uncertainty

There are no assurances the wireless network coverage will be complete. There are concerns the signal will not reach interior rooms, or above the second floor. Individuals in these situations will need to purchase a repeater box which can cost as much as $150   Sony VAIO PCG-6S2L Battery .

Even then, the box would need to be placed in a location that can get a signal in the first place.

Length of Contract

The city of San Francisco’s contract with Earthlink consist of 4 four year terms which are automatically renewed. This could leave San Francisco at the mercy of EarthLink in terms of network maintenance and upgrades   Sony VAIO PCG-6S3L Battery .

Connection speed

The free service would be 300 kbit/s, 1/3rd the speed of what other cities are getting in their wifi deals.

Possible Alternatives

One possible alternative to such an institutionalized wireless system, is the product line from Meraki The mini  Sony VAIO PCG-6V1L Battery ,

a low-cost and lower power type of repeater box, assists in creating a free wi-fi network by allowing users to broadcast their unused bandwidth and coordinate this with bandwidth broadcasted by other Minis in its area. While it may not be a feasible city-wide plan, and raises some serious terms of service questions with ISPs   Sony VAIO PCG-6W1L Battery ,

it shows some creativity and demonstrates an alternative to the massive plan set to move forward in San Francisco.

Existing is SFLAN, a project of the Internet Archive, for over five years is San Francisco's first and only prolific community Wi-Fi network      Sony VAIO PCG-6W2L Battery .

It boasts network neutrality and ample bandwidth without any additional or special hardware other than one's current wireless devices. Its difference is its solid, stable connection when wireless equipment is mounted on the roof of a building plus the ability to maintain a wired inside environment       Sony VAIO PCG-6W3L Battery .

Wi-Fi operating system support usually consists of two pieces: driver level support, and configuration and management support.

Driver support is usually provided by multiple manufacturers of the chip set hardware or end manufacturers   Sony VAIO PCG-7111L Battery .

Also available are Unix clones such as Linux and FreeBSD, sometimes through open source projects.

Configuration and management support consists of software to enumerate, join, and check the status of available Wi-Fi networks. This also includes support for various encryption methods       Sony VAIO PCG-7112L Battery .

These systems are often provided by the operating system backed by a standard driver model. In most cases, drivers emulate an Ethernet device and use the configuration and management utilities built into the operating system        Sony VAIO PCG-7113L Battery .

In cases where built in configuration and management support is non-existent or inadequate, hardware manufacturers may include their own software to handle the respective tasks.

Microsoft Windows

Microsoft Windows has comprehensive driver-level support for Wi-Fi, the quality of which depends on the hardware manufacturer  Sony VAIO PCG-7133L Battery .

Hardware manufactures almost always ship Windows drivers with their products. Windows ships with very few Wi-Fi drivers and depends on the original equipment manufacturers (OEMs) and device manufacturers to make sure users get drivers. Configuration and management depend on the version of Windows      Sony VAIO PCG-7Z1L Battery .

  • Earlier versions of Windows, such as 98, ME and 2000 do not have built-in configuration and management support and must depend on software provided by the manufacturer
  • Microsoft Windows XP has built-in configuration and management support        Sony VAIO PCG-7Z2L Battery .
  • The original shipping version of Windows XP included rudimentary support which was dramatically improved in Service Pack 2. Support for WPA2 and some other security protocols require updates from Microsoft. Many hardware manufacturers include their own software and require the user to disable Windows’ built-in Wi-Fi support  Sony VAIO PCG-8Y1L Battery .
  • Windows Vista and Windows 7 improved Wi-Fi support over Windows XP with a better interface and a suggestion to connect to a public Wi-Fi when no other connection is available     Sony VAIO PCG-8Y2L Battery .

Mac OS X and classic Mac OS

Apple was an early adopter of Wi-Fi, introducing its AirPort product line, based on the 802.11b standard, in July 1999. Apple later introduced AirPort Extreme, an implementation of 802.11g         Sony VAIO PCG-8Z1L Battery .

All Apple computers, starting with the original iBook in 1999, either included AirPort 802.11 networking or were designed specifically to provide 802.11 networking with only the addition of the internal AirPort Card (or, later, an AirPort Extreme Card), connecting to the computer's built-in antennae        Sony VAIO PCG-8Z2L Battery .

All Intel-based Macs either come with built-in AirPort Extreme or a slot for an AirPort card, and all portable Macs (all MacBooks and the earlier iBooks and PowerBooks) have included Wi-Fi for several years. In late 2006, Apple began shipping Macs with Broadcom Wi-Fi chips that also supported the Draft 802.11nstandard        Sony VGP-BPS21 Battery ,

but this capability was disabled and Apple did not claim or advertise the hardware's capability until some time later when the draft had progressed further. At the January 2007 Macworld Expo, Apple announced that their computers would begin shipping with Draft 802.11n support         Sony VGP-BPS21A Battery .

Systems shipped with this hidden capability can easily be unlocked through software, but due to the accounting requirements of Sarbanes-Oxley, Apple cannot freely add features to already-sold hardware and so must nominally sell an upgrade. This "upgrade" is included in the price of an AirPort Extreme Base Station for all computers owned by the purchaser   Sony VGP-BPS21B Battery ,

and Apple sells the "upgrade" separately (as the "AirPort Extreme 802.11n Enabler for Mac") for about US$2 in the United States and at similar prices elsewhere.

Apple produces the operating system, the computer hardware, the accompanying drivers, AirPort Wi-Fi base stations   Sony VGP-BPS21/S Battery ,

and configuration and management software, simplifying Wi-Fi integration, set-up, and maintenance (including security updates). The built-in configuration and management is integrated throughout many of the operating system's applications and utilities  Sony VGP-BPS21A/B Battery .

Mac OS X has Wi-Fi support, including WPA2, and ships with drivers for all of Apple’s current and past AirPort Extreme and AirPort cards. Many third-party manufacturers make compatible hardware along with the appropriate drivers which work with Mac OS X’s built-in configuration and management software            SONY VGP-BPS21 Battery .

Other manufacturers distribute their own software.

Apple's older Mac OS 9 supported AirPort and AirPort Extreme as well, and drivers exist for other equipment from other manufacturers, providing Wi-Fi options for earlier systems not designed for AirPort cards       SONY VGP-BPS21A Battery .

Versions of Mac OS before Mac OS 9 predate Wi-Fi and do not have any Wi-Fi support, although some third-party hardware manufacturers have made drivers and connection software that allows earlier OSes to use Wi-Fi.

Open source Unix-like systems

Linux, FreeBSD and similar Unix-like clones have much coarser support for Wi-Fi           SONY VGP-BPS21B Battery .

Due to the open source nature of these operating systems , many different standards have been developed for configuring and managing Wi-Fi devices. The open source nature also fosters open source drivers which have enabled many third party and proprietary devices to work under these operating systems            SONY VGP-BPS21/S Battery .

See Comparison of Open Source Wireless Drivers for more information on those drivers.

  • Linux has patchy Wi-Fi support.Native drivers for many Wi-Fi chipsets are available either commercially or at no cost, although some manufacturers don't produce a Linux driver, only aWindows one        SONY VGP-BPS21A/B Battery .
  • Consequently, many popular chipsets either don't have a native Linux driver at all, or only have a half-finished one. For these, the freely available NdisWrapper and its commercial competitor DriverLoader allow Windows x86 and 64 bit variants NDIS drivers to be used on x86-based Linux systems and 86_64 architectures as of January 6, 2005  SONY VGP-BPS13/Q Battery .
  • As well as the lack of native drivers, some Linux distributions do not offer a convenient user interface and configuring Wi-Fi on them can be a clumsy and complicated operation compared to configuring wired Ethernet drivers      SONY VGP-BPS13/Q Battery .
  • This is changing with the adoption of utilities such as NetworkManager and wicd that allow users to automatically switch between networks, without root access or command-line invocation of the traditional wireless tools.
  • FreeBSD has Wi-Fi support similar to Linux        SONY VGP-BPS13B/Q Battery .
  • Support under FreeBSD is best in the 7.x versions, which introduced full support for WPA and WPA2, although in some cases this is driver dependent. FreeBSD comes with drivers for many wireless cards and chipsets, including those made by Atheros, Ralink, Cisco, D-link, Netgear, and many Centrino chipsets        SONY VGP-BPS13B/Q Battery ,
  • and provides support for others through the ports collection. FreeBSD also has "Project Evil", which provides the ability to use Windows x86 NDIS drivers on x86-based FreeBSD systems as NdisWrapper does on Linux, and Windows amd64 NDIS drivers on amd64-based systems        SONY VGP-BPS13A/Q Battery .
  • NetBSD, OpenBSD, and DragonFly BSD have Wi-Fi support similar to FreeBSD. Code for some of the drivers, as well as the kernel framework to support them, is mostly shared among the 4 BSDs.
  • Solaris and OpenSolaris have the Wireless Networking Project to provide Wi-Fi drivers and support.
  • Android has built in support for WiFi, with it being preferred over Mobile telephony networks.

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