WIRELESS NETWORKING IN SCHOOLS
Why is wireless computing so popular in education? It is easy and it works!
(plus given a choice many students will choose a wireless notebook rather than a desktop)
Notebook computers using wireless networking offer great flexibility in classrooms!
by Keith Lightbody - Facilities Consultant - last updated 3 August 2009
1. New South Wales to spend $70 million over three years to fit out 463 secondary schools with secure, scalable wireless connectivity
so 232,000 secondary school students and 25,000 teachers can benefit from the federal Government's $2 billion digital education revolution
2. The One Laptop Per Child initiative will help make notebook/laptop computers
much more affordable for schools and students http://laptop.org/
3 . The Victorian Department of Education and Training (DET) in Australia has completed possibly the world's largest enterprise
wireless network with 10,000 access points spread over 1700 education sites across the entire state (see link).
1. Quick Start
3. Recent Advances
4. Possible Uses
5. When Buying
6. Select Products
7. Tech Details
8. Health & Safety
13. Helpful Resources
14. Site Credits
Quick Start: A school can quickly add wireless networking to their existing
network infrastructure however first check with the Principal for any related
policies or technical compliance requirements. One way to start is to organise
a qualified company to work with your network manager to arrange a wireless
site survey - this can measure how the radio signal strength varies through
your school walls, fittings and furniture - which then allows a calculation
of the number of wireless access points needed for full site coverage. To see
how easy it is you could try it at home first: buy a kit with at least one wireless
base station and a wireless card - plug in the base station, put the card into
a notebook and check the coverage yourself.
- purchase a wireless base station (access point)
- use existing data outlets (or install additional points)
- use existing power outlets (or use Power over Ethernet)
- buy and install a wireless card for each mobile computer
- connect the base station into an active (live) network point
- locate the base station at least half a metre away from the nearest person
(e.g. 2 metres above the floor on a wall, on the top of a rack in a communications cupboard, in the ceiling)
- use the software provided to configure the base station to access an appropriate part of your network
- verify that security features are enabled to protect the network
- configure any necessary settings on each computer
- adjust the base station antenna for best possible coverage
- if necessary reposition the base station to get the best possible coverage
This technology is much less intrusive in a classroom! Once a few teachers find success others will want the same advantages. Wireless notebook technology has proved popular in schools around the world. However for the best results qualified installers need to verify wireless coverage and security. Relevant professional development with good support is another essential part of the package - then teachers really can empower student learning with technology.
In most cases it is recommended that a school have high bandwidth optic fibre cable between buildings, suitable network switches and a reasonable number of physically cabled data points. This allows the maximum speed of data transfer and minimises the amount of radio traffic required for network coverage. It is also essential to have well managed and highly reliable network servers. Schools can install different ratios of cabled to wireless devices as required - the guiding principle should be the needs of the students and staff - however larger numbers of notebooks will require more access points.
Maximum flexibility is gained by using notebook (laptop) computers. Each computer can then access network software, printers, the World Wide Web (WWW), email and other network resources from anywhere within range of the wireless signal (typical use is over distances less than 30 metres). This allows anywhere, anytime learning - where the computer tool shifts to the learning! - not the learning moving to the tool. An early example was Quinns Beach Primary School in Western Australia - they chose 60% notebook to 40% desktop computers for maximum flexibility and extremely high utilisation rates. This contrasts to many schools where notebook computers are in the minority. Note: to allow the full potential use of computers all classrooms at Quinns have both cabled and wireless access.
Notebook users can do low bandwidth tasks and stay completely mobile. Wireless networks cope well with low to moderate bandwidth tasks such as those mentioned above. An average user may use low bandwidth 80% of the time. However for fast access on high bandwidth tasks they can plug into the network. Some high bandwidth tasks include use of video files, computer assisted drafting or working with large graphics files. These are currently best done on computers physically plugged into the LAN via a fast network card (e.g. 100 Mbps). Very high bandwidth tasks such as editing video are still best done on local hard drives or with high speed external drives (e.g. Firewire, USB2).
2. Benefits: Wireless notebook computers can transform teaching. It is easier to use wireless notebook computers and they are less intrusive in a classroom! Schools can offer better technology access for students with disabilities or behavioural issues. Students using wireless notebooks show much greater integration of the technology within lessons than desktop computers - even when desktops are arranged in collaborative clusters. Wireless networks provide great freedom for the users - offering anytime, anywhere learning. It allows students greater movement, permits easy showing of work to fellow students and offers greater opportunity for collaboration. Students can use wireless notebooks wherever they are learning! Inside at desks, in bean bags, on the floor, outside on benches, on the grass or under a tree. Wireless networks provide constant access to critical information (e.g. for teachers to access student assessment records). A combination of notebook computers and wireless networking provides great flexibility for different class sizes and multi mode teaching spaces (e.g. in middle schooling). Wireless networks allow smaller more mobile devices that save space in the classroom and allow better teacher vision. They also help reduce the tangle of cables.
Another advantage is that wireless notebooks require less change by the teacher to classroom routine. Teachers who have been reluctant to use technology may find the advantages now outweigh the disadvantages. Wireless notebooks can be used in a variety of different ways so are suitable for a range of teaching styles. Teachers appreciate the easy visual supervision of students - no longer are heads obscured by clunky desktop computers or monitors. The notebook computers are small, light and can be easily shifted around the classroom.
Wireless base stations or access points using 802.11b or 802.11g can cover 25 to 100 metres depending on obstructions while 802.11a has a much lower area of coverage. 802.11b allows up to 10 concurrent users to happily share the bandwidth - it is possible to have 20 to 30 concurrent users but access speeds may be unsatisfactory unless students are on very low bandwidth tasks. The higher speed 54 Mbps products using 802.11a or 802.11g provide higher bandwidths which means a larger number of concurrent users can comfortably share the signal. Coverage can be improved by optimum selection of antennae. Base stations offer quick deployment and can be easily redeployed. It is easy to add a wireless networking card to modern notebook computers. Wireless networking can be easily integrated with an existing LAN management infrastructure.
Wireless LANs are particularly well suited to places where traditional Ethernet networks are too expensive or too difficult to install (e.g. heritage buildings). They are useful for providing network coverage in lecture theatres, open plan buildings or larger areas such as outdoors. Wireless networks can be easily moved. They often reduce the need for large centralised computer laboratories.
Recent Advances: People like the convenience of wireless so it is rapidly
growing in popularity. The IEEE 802.11n draft standard is progressing - it incorporate
new technologies (multiple receivers and transmitters) for increasing the throughput
- possibly up to 600 Mbps - much faster than the speed of 11g. Some 11n draft
products released in 2006 achieved up to 100 Mbps but also affected existing
11b or 11g systems. Draft products may need software or hardware updates when
the standard is finally ratified so it is too soon to consider 11n for widespread
deployment. Another contender is Ultra WideBand (UWB) - it allows high data
rates over distances less than 10 metres and offers a possible replacement for
USB or Firewire cables - it is also capable of resolving location information
similar to a GPS.
Wireless survey tools continue to become more powerful with laptop-based site survey software (e.g. AirMagnet Survey 3.0) and integrated radio frequency spectrum analysis software (e.g. Spectrum Analyzer 2.0) making it much easier to find problem areas and fix dead spots.
The Massachusetts Institute of Technology (MIT) can now map wireless users across campus - it provides information on exactly how many people are logged on in different locations at any given time. MIT researchers developed electronic maps that tracked the devices people use to connect to the network (e.g. notebooks, wireless personal digital assistants (PDAs), Wi-Fi equipped cell phones). Red areas on the map show the highest concentration of wireless users on campus so students can plan to avoid the congested areas.
The current marketing of tri-mode 802.11 a/b/g PC cards allows wireless connection by users at sites running any of the 3 common wireless standards currently in use. The most popular installation in 2007 is still 802.11g. It will be critical that any new 802.11n equipment is completely compatible with earlier a/b/g cards and does not interfere with a/b/g access points.
The introduction of Centrino technology in Windows notebooks during 2003 was very significant - more efficient power management has resulted in 4-6 hour battery life and the internal wireless cards are more robust in schools.
The IEEE ratified the 802.11g standard on 12 June 2003. Testing in February 2003 at 2 WA schools showed clear benefits with using 802.11g systems - the coverage was very similar to existing 802.11b systems but with much greater range (at least double) compared to 802.11a systems tested in the same buildings. Better still the new 802.11g cards worked perfectly with existing 802.11b base stations even though they were a different brand.
Many schools have installed wireless networks after realising the advantages. In a Dec 2002 survey of 45 teachers from 4 WA schools who had spent the year using wireless notebooks an indication of success was that the majority of teachers recommended an increase in the ratio of notebooks to desktops (they were using between 30% to 60% wireless notebooks in the 4 schools).
The survey confirmed that teachers and students enjoy the greater freedom, mobility and versatility of using wireless notebooks in their own classroom. Teachers commented on the 'better fit' of notebooks in normal size classrooms, the ease of use of wireless notebooks for collaboration and that wireless notebooks provided more flexibility for group work. Wireless notebooks also better allowed multiple activities in the same room and more customised learning. However issues raised included managing battery life, the time taken to pack up a trolley of 10 or more notebooks, preventing damage to cords or chargers, occasional problems with protruding wireless cards and the need for more careful handling of notebooks (less robust than desktop computers).
In 2003 most interest for new systems was in 54 Mbps 802.11g (with 802.11a for certain situations and 802.11b still popular for existing installations). Previously schools mainly installed 11 Mbps 802.11b systems but late in 2002 a few schools introduced 802.11a base stations and cards. They offer about 5 times the bandwidth, support more users and allow up to 12 zones (compared to only 3 zones for 802.11b or 802.11g). Unfortunately 802.11a products are more expensive, have a much reduced range and few are compatible with 802.11b systems. However 802.11a is ideally suited for use in wireless bridges which offer a convenient and flexible way to connect temporary classrooms. In January 2003 Apple released the first commercial 802.11g systems at very attractive prices. At present the 802.11g option is gaining ground at prices very similar to last years 802.11b prices. A mixture of products is also possible with some dual homing base stations and access cards now available.
Older Windows Celeron, Pentium II, III or IV notebooks (non Centrino) can use the PC card slot for connecting to a wireless network. However the protruding antenna part of the wireless card requires care to avoid damage. Internal wireless cards (such as those found in the Centrino) offer significant advantages. The Mac iBooks and Powerbooks have always had a more robust internal Airport card slot and also an internal aerial. The new Airport Express cards are also internal. Fortunately the growing importance of wireless networking has resulted in Windows notebook manufacturers offering better wireless options. Internal cards in notebook (notebook) computers typically connect to an antenna built in to the notebook lid. When the notebook lid is raised the higher and wider internal antenna provides better range than a protruding 'stub' aerial on a PC card. It is also usually safer for the user. Desktop computers can also have wireless cards added via internal PCI card slots (Windows) or internal Airport card slots (e.g. Apple iMac, G4, G5).
A wide range of special antennas can be used to direct the signal or improve service. These include directional, high gain, mast mount, multiple array and smart antennas.
In the future third generation (3G) mobile services, Bluetooth (used in personal area wireless connectivity), personal digital assistants (PDAs), Voice over Internet Protocol (VoIP) telephony and other mobile technologies using wireless will find growing use in education.
HISTORY: Early wireless LANs were very expensive and relatively slow (low bandwidth). The arrival of the affordable 11 Mbps 802.11b standard in late 1999 was a turning point. Lower costs, the introduction by Apple of easy to use wireless networks (AirPort) and the availability of off-the-shelf chip sets quickly reduced costs. In 2000 the significantly lower prices and the increased bandwidth made the use of wireless networking in classrooms attractive to education. In 2001 more teachers appreciated the greater flexibility - notebook computers combined with wireless networking provided basic Internet, print and software needs for students anywhere in the classroom.
Possible Uses: The use of wireless networking can:
- boost productivity (the computer is at hand - ready for use)
- provide technology access for students with disabilities
- support dynamic class sizes or flexible teaching spaces
- improve sharing or utilisation of computers (mobile location)
- support the use of notebooks in all parts of the curriculum
- provide network access in large open areas such as libraries, halls or theatres
- support sports training or athletics competitions
- allow widespread network access in notebook for teacher programs
- provide network access in heritage buildings
- allow rapid deployment of extra networking for special events (e.g. open days, parent evenings, drama performances)
- offer flexibility within science laboratories, art, D & T or other unique learning environments
- provide roaming network access for notebook computers
- wireless IP Phones
- (please email suggestions to add to this list)
One interesting feature is that some wireless cards allow computer-to-computer (peer-to-peer) connection without a base station. Bryn Jones mentioned an example where a group of Australian Apple Distinguished Educators were delayed at Adelaide airport - he and his colleagues quickly set up a wireless network of notebook computers in the Qantas lounge and exchanged documents, projects, photos and shareware. Similarly students can set up their own private peer-to-peer networks - however management of this feature may require some additional policies or strategies in a school situation.
Wireless networks are also suitable for other locations such as homes, small offices, warehouses, airport terminals, hospitals, department stores and restaurants.
Some features to consider in wireless networking products:
- performance (Mbps throughput)
- site survey and placement tools
- interoperability: some items from different vendors do not work well together
- simple installation of hardware and software
- easy base station and client-configuration management software
- comprehensive security: protection from unauthorized use of your network or viewing of file traffic
- adjustment of cell coverage or signal strength
- multiple operating channel frequencies
- roaming of clients across multiple base stations (not a feature on all products)
- real time statistics and monitoring of system status
- IP addressable base station
- separate or inline power supply
- diagnostic and signal measurement tools
- fully compliant with the 802.1x standards
- WiFi certification (different brand wireless products are interoperable)
- well engineered and designed
- centralised management for multiple base stations
- ability to detect and deny network access to rogue access points
- physical security of wireless base stations (anti-theft features that do not interfere with the signal)
- ability to update firmware
- feature-rich products
Prior to installation some extra data points may be required to locate the base stations in a position for optimum wireless coverage. With Power over Ethernet there is no need to install adjacent power points for each base station. It is important to consider health and safety issues. A site survey is recommended to determine the optimum placement of base stations as different building materials and designs will restrict the wireless signal in unique ways. Common base station placement is on a central wall approximately 2000 mm (2 metres) above the floor. Some sites mount access points in the ceiling for greater security and to prevent theft but physical access can be a problem. Fortunately web based site management software allows easy checking and configuration of access points across a whole school site without any need for physical access. Some schools have also had success with base stations located on the top of the rack in a communications cupboard.
users may require
- multiple base stations to allow campus wide roaming
- multiple cards in base stations to increase the bandwidth
Selected Products: Selections
below are available in Western Australia,
are for education in Australian $ inc. GST, ***
recommended models (more stars is better).
Companies that supply wireless cards include Apple, Belkin, Cisco, D-Link, Intel, Lucent, Netgear, 3Com, Symbol, Toshiba and Xircom. Prices range from $50-$150.
Base Station (Access Points
Companies that supply base stations include Apple, Belkin, Cisco, D-Link, Enterasys, Ericsson, Intel, Lucent, Netgear, 3COM and Toshiba. Prices range from $150-$1500. Additional information is available via links in the Other Resources section below.
7. Technical Details: The 802.llx standard was designed by the Institute of Electrical and Electronics Engineers (IEEE) and adopted by the Wireless Ethernet Compatibility Alliance (WECA). Compatibility testing has resulted in high rates of interoperability of equipment for each standard from different suppliers. However some schools have had technical problems when a mix of equipment was in use - in at least 2 cases the easiest way was to adopt a single vendor solution on that site. 802.11b devices use Direct Sequence Spread Spectrum (DSSS) transmission. Base stations (access points) and wireless cards in computers using 802.11b and 802.11g communicate via the 2.4 GHz radio band. Devices using 802.11a communicate via the 5 GHz radio band. The wireless signal can reach anywhere from 25 - 100 metres from the base station - it does not stop at the school boundary. Current performance varies from up to 11 Mbps for 802.11b to 54 Mbps for 802.11a and 802.11g. Some non-standard solutions offer up to 108 Mbps.
The method of spreading a transmitted signal in the radio spectrum was first developed around 1945 by the military. Spread Spectrum Transmission was designed to provide a radio transmission method that was low in power, reliable, and robust against interference. In 1990 two of the four methods of spread spectrum transmission developed by the military were released for commercial use.
Health & Safety: The instruction manuals for wireless devices (often
only pdf files on the installation CD-ROM) usually include a number of cautions.
Some examples are shown below.
CAUTION: Do not touch or move antenna(s) while the unit is transmitting or receiving.
CAUTION: Do not hold any component containing the radio so that the antenna is very close or touching any exposed parts of the body, especially the face or eyes, while transmitting.
One solution could be to
attach a prominently displayed warning sticker to all wireless devices in schools.
This allows all users ready access to health and safety information. The sticker
should clearly indicate the recommended safe distances for an operating device.
Some examples are shown below.
High gain, wall or mast mount antennas should be more than 30 cm from your body.
Dipole antennas on base stations should be more than 15 cm from your body.
The antenna on wireless cards in notebooks should be more than 5 cm from your body
(NOTE: the actual location of the antenna is not disclosed for many laptops - if it is imbedded around the screen
then it may provide sufficient clearance for laptop computers to actually be used safely on laps)
Current information suggests that a wireless network client device working at one-fiftieth the power output of a mobile phone handset and 50 cm away from the student's body is much less capable of affecting the cells of the body than a mobile phone. It depends on the type of transmissions, the distances, and other factors, but it is most likely that a wireless LAN unit has the potential to cause biological changes which in the worst case is only 1% that of the normal mobile phone held against the head (reference: Stewart Fist).
Students should be aware that the parts of a human considered most susceptible to RF radiation are the eyes, brain, nervous system, immune system, kidneys, ovaries and testes. Students should not use notebook computers in their laps if the base of the computer contains a wireless antenna requiring a clearance greater than 5 cm from the body.
It is important to consider the level of radiation in the school environment given that students are in schools for about 12,000 hours of their lives (assuming 5 hours per day, 200 school days per year, 12 years at school).
Electromagnetic energy is all around us. Modern homes and offices have many radio frequency (RF) producing devices (e.g. computers, cordless phones, microwave ovens, fax machines). All radio equipment emits radio frequency electromagnetic energy. Spread spectrum wireless equipment is a very low power radio device by comparison. Some typical examples:
Wireless base station
Mobile (cellular) phone
Mobile (cellular) phone car kit
500,000 to 1,000,000 mW
During a phone call a mobile phone may emit 20 times more energy than an active wireless base station (or 50 times more energy than an active wireless card client adapter). A mobile phone continues to emit radio energy even while on stand-by. However most wireless networking equipment is only active while it is transmitting.
In January 2006 testing of wireless networking radiation levels was carried out at the Glennie School in Toowoomba, Queensland. All measurements were found to be well below the general public reference level with the maximum reading measured from the wireless network of only 5% of the general public reference level. The maximum environmental reading was 0.0049% of the general public reference levels and the maximum reading when 10cm from the school notebook computers was only 1% of the general public reference level. For more details visit http://www.glennie.qld.edu.au/facilities/technology5.asp To download the complete RF (Radio Frequency) Hazard Survey report (pdf 1.2M) visit http://www.glennie.qld.edu.au/facilities/Glennie_School_RFHCD.pdf Testing was also conducted in August 2001 at Quinns Beach Primary School and Sevenoaks Senior College. The testing indicated that wireless networking equipment used in these West Australian schools has radiation levels 400 times lower than the Australian Standards. Measurements were made by Radhaz Consulting http://www.radhaz.com.au The measured levels near an actively transmitting base station were less than 0.0005 mW/cm2 at all sites for distances greater than 10 cm (the test equipment used could not provide valid measurements for distances less than 10 cm). Measurements at Sevenoaks SC were made with a Cisco 340 base station and Windows notebook with protruding Cisco wireless PC client adapter card. Measurements at Quinns Beach PS were made with a Lucent Orinoco AP-1000 base station and Apple iBook1 with internal Airport wireless card.
The Australian reference levels standard at the time of testing required a power density of less than1 mW/cm2 for occupational workers and 0.2 mW/cm2 for general public [extracted from Australian Standards AS/NZS 2772.1 (Int):1998 Maximum RF Exposure Limits (10-300 000 MHz) - for current information visit http://www.aca.gov.au/standards/index.htm]
A resource by John E. Moulder (Professor of Radiation Oncology) that addresses some commonly asked questions is 'Cellular Phone Antennas (Mobile Phone Base Stations) and Human Health' http://www.mcw.edu/gcrc/cop/cell-phone-health-FAQ/toc.html - this FAQ contains detailed answers that include graphs, explanatory diagrams and further references. Additional information is included in the Technical Information Statement 'Human Exposure to Radio Frequency and Microwave Radiation from Portable and Mobile Telephones and Other Wireless Communication Devices' (September 2000) at http://www.seas.upenn.edu:8080/~kfoster/phone.htm
A further indication of the lower signal strength of wireless networking is the installation of wireless networks in Childrens Hospitals. One example is a Lucent Orinoco wireless base station in the Paediatric Intensive Care Unit of the Princess Margaret Hospital for Children in Perth, Western Australia. The wireless network is used to allow doctors and nurses to access information without having to leave the bedside (in contrast mobile phones are not normally allowed in Intensive Care Units). View the story 'Wireless Enhances Care at Princess Margaret Hospital' (27/03/2001) in the Case Studies area of the Integrity Data Systems web site at http://www.IntegrityData.com.au for more details. The Sheffield Children's Hospital in the United Kingdom also uses wireless networking successfully and safely. Extensive investigation took place prior to selection to ensure radio waves would not interfere with critical medical equipment. The Enterasys RoamAbout solution supports desktop, notebook and hand-held devices (Compaq iPAQs). For more details of how children within the hospital have wireless Internet connectivity and e-learning facilities visit http://www.enterasys.com/corporate/pr/releases/2001/jun/6-11.html
Despite the measurements and the information mentioned above there has already been one case where parents have launched a class action lawsuit over concerns about wireless radiation. A complaint by parents in Oak Park Elementary School District was filed on 26 September 2003 in the Circuit Court of Cook County in Illinois, USA. A copy of the complaint is available online at http://www.nsba.org/cosa2/wireless.pdf (1.8 MB). For more details view http://abcnews.go.com/sections/scitech/Living/WiFi_lawsuit_techtv_031111.html An alternative view is offered at http://www.stargeek.com/item/24194.html
A different health issue to consider is the combined weight of books plus a notebook computer if a student needs to carry the notebook around in a school bag. Other ergonomic issues should also be considered if students are using notebooks for long periods.
9. Security (of data): It is critical that wireless base stations are not added to a network without first ensuring adequate security arrangements. The level of security required will depend on the sensitivity of data on the network. Currently there are many wireless packet analysers available for download from the Internet e.g. AirSnort, NetStumbler. There are also commercial products for analyzing Wireless Local Area Networks (WLANs) e.g. AirMagnet. These can be very useful for site surveys and checking the security of an installed wireless network. However these tools can also be used by hackers.
Some early wireless network security specifications had flaws e.g. the 802.11b Wired Equivalent Privacy (WEP) 40-bit encryption protocol allowed hackers to intercept transmissions from a notebook, read the contents and modify them without detection. There have been a number of reports of hackers using notebooks or PDAs to 'drive by' or 'ride elevators' until they pick up a signal from wireless networks. One example in Perth, Western Australia involved hackers flying around in a light aircraft probing wireless networks.
Another risk is from 'rogue' wireless base stations. This can happen when a person plugs in an unauthorised wireless base station - there have been cases where this generated random errors on the network which took days to identify. Without adequate security at the users computer a rogue wireless base station could also be used to trick users into providing sensitive information. Schools can further reduce risks by turning wireless access off after hours, during vacations or long breaks - this can be done in a number of ways. For larger installations a centralised WLAN management system (e.g. Blue Socket) can address all these issues.
For higher security requirements there are now a range of encryption standards. Newer wireless base stations may also include firewall or other validation strategies so that only authorised users are granted wireless access. There are a range of authentication processes available - these include the use of a RADIUS server or one of a number of types of Extensible Authentication Protocol (EAP) e.g. EAP-MD-5, EAP-TLS, EAP-LEAP, EAP-TTLS. Security features must be correctly activated to fully protect data and servers. One problem with encryption enabled is that a bandwidth overhead (e.g. up to 20% on some 128-bit encryption) can result in slower data transfer rates - this is not an issue if encryption is done in hardware rather than software.
Even if the data being transmitted is not considered 'sensitive', unrestricted access may mean network servers are at risk. A secure wireless network requires both validation of the user and verification that the user has connected to the intended network (multiple wireless networks may be present in one location).
However in conjunction with providing adequate wireless security it is essential that unattended desktop computers physically connected by cable to the network are also secure.
Security (of wireless devices): Wireless access points must be securely attached or they can be stolen. Vandalism may also be an issue in some sites. Similarly some PC wireless cards (client adapters) can be easily removed, stolen or damaged - especially if they have an external antennae that protrudes from the side of the notebook. Even internal wireless cards are at risk from theft as it may not be noticed immediately that someone has removed the card. It is essential in all cases that the risk of theft is minimized.
Security (of notebooks): see below.
10. Notebook Computers: Wireless networking commonly involves extensive use of notebook (notebook) computers. Some private schools require students to purchase their own notebook computers. Students in government schools typically share notebook computers. Issues that arise include keeping the battery charged, securing notebooks from theft, protecting notebooks from excessive wear and tear (particularly the expensive screen). It is critical that all students and teachers understand the need for careful treatment of "shared resource" notebooks - any lack of care or rough treatment will greatly increases costs and also lead to frustrated users. Buy notebooks with internal wireless cards (protruding wireless cards require special care - it is best to avoid these in schools). Consider 12" screen models if students are part of a 1:1 program where they need to carry the notebook around school or to and from home. Be aware that large notebook/laptop screens can be a drain on battery life and budget without any significant educational benefit. With long periods of use ergonomic issues will also need to be addressed.
One strategy being used in WA schools is the use of secure metal storage cabinets or mobile trolleys (carts) that allow for transport, storage and overnight charging. Designs are available to store from 8 - 32 notebook computers. As notebooks or notebooks are very portable some schools choose the simpler and cheaper cabinets which are bolted permanently to a wall. Some issues to consider for mobile trolleys include the weight, handles for pushing, stability, flexibility of internal spaces, power points for charging, fabric lined shelves that are non scratching, cable management and the type of wheels. A smaller (up to 10 notebooks) style trolley manufactured in Australia is the iTrolley (shown below on left) http://process-systems.com.au/computer_trolleys.html A larger (up to 20 notebooks) style of metal cabinet trolleys (shown below in centre) was produced locally by FoxIT. Another style of trolley with high visibility (shown below on right) is made locally by PC Locs - they have a complete range of trolleys (from 6-28 notebooks) http://www.laptoptrolleys.com/laptopcarts.htm Overseas countries offer similar products e.g. Technology on Wheels Systems (ToWS) in Malaysia http://www.tows.com.my/default.asp plus there are a range of notebook carts available in the USA http://earthwalk.com/Products/mobilelabs.html, http://www.pc-security.com/products_solutions/carts_cabinets_cases/mobile_notebook.htm and http://www.bretford-central.com/Bretford-LAP24E-BR1371.html
Temperature control and electrical earth leakage safety devices are highly recommended. A number of Australian mobile trolleys have been made with these features. Australian standards require a maximum 10 Amps of current through standard power leads - trolleys with 20 - 30 notebooks require multiple power leads or a power cycling system for charging.
Teachers with their own notebooks also require some security options. One personal option is the use of securing cables - a wide variety are available from PC Locs http://www.computerlocks.net/index.htm However the West Australian companies above have also developed a personal 'steel lunchbox' style of security cabinet to hold one notebook computer. It can be bolted in many locations including under a teachers desk. A similar notebook cabinet is available from http://www.blackbox.com.au/ Another option is steel storage cabinets that can be bolted to a wall - they can typically hold 4-8 notebook computers.
It is absolutely critical that the notebook computers are well configured, have suitable software and do not require complex login procedures. They need to be well maintained and handled with care. They are more expensive but can be shared successfully if clear standards for use are set and followed. A procedure for documenting and dealing with any hardware or software problems is essential. Other strategies include buying notebooks with 3 or 4 year warranties and purchasing some form of insurance or service contracts.
Security needs to be handled in a systematic way that is not too time consuming - trolleys or storage places with clear vision of the number of notebooks present prior to lockup are ideal. If students are required to use a borrowing system it may be possible via a library card or ID badge left with the teacher. There needs to be clear communication of how many notebooks each teacher is responsible for at the end of the day.
In order to ghost large images (say 5 - 10 GB) to notebooks in an acceptable amount of time consider the fastest ethernet switches that you can afford. In schools with multiple sets of notebooks consider cabling the technicians area with at least 30 data outlets on shelves so that whole batches of laptops can be updated via the network at high speed (see photo below). Other methods used locally are to plug in a whole heap of notebooks in either the library or a computer room - any where with suitable space and enough data outlets to do the job in bulk. Alternatively connect a fast 24 port switch on top of a trolley and use ethernet leads to plug in the laptops while they are still on charge. Please email me if you require more information.
Never buy notebooks for schools without excellent battery life. Notebooks that have obvious charge lights (see photo above) really help with management.
It does not matter if a school starts off with just a few wireless notebooks. Once some teachers have success and administrators see high utilization rates then the justification for a higher proportion of notebook computers is established.
Some current trends supporting
greater use of wireless notebooks include:
- bulky notebooks being replaced by lighter notebook computers
- less performance or feature gap between desktops and notebooks
- availability of economical entry level notebooks
- longer battery life in notebook computers
examples include -
A. There is no need for cabling if a site is using wireless networking
For best network performance most schools will still need to be physically cabled with an optic fibre Gigabit backbone and Ethernet data outlets distributed wherever high bandwidth may be required. A combination of cabled and wireless provides a comprehensive solution. Each wireless base station is plugged into a data outlet selected to give maximum coverage. Typical base station placement is on a central wall approximately 2 metres above the floor. A site survey is necessary to determine the optimum placement of base stations as different building materials and designs will restrict the wireless signal in unique ways. Security mesh grills are particularly effective in blocking the wireless signal.
networking is too slow to be useful
Wireless networking is definitely fast enough for many common school tasks. The 11 Mbps standard was used effectively in multiple classrooms in more than 50 schools in Western Australia. After 2004 the 54 Mbps standard enabled most typical school tasks to be completed with ease. Many schools now have wireless coverage over their entire campus. The key to success is to have adequate cabling for high bandwidth tasks and to limit the number of users on each wireless base station.
backbone - high capacity optic fibre cable carrying network traffic between major buildings
base station (access point) - allows shared wireless access to the network
cell - area of wireless coverage of a single base station
DSSS - Direct Sequence Spread Spectrum sends data in small pieces over a number of discrete frequencies (less efficient use of bandwidth than frequency hopping spread spectrum but more suitable for bandwidth sharing)
IEEE 802.1x - range of wireless standards adopted by Institute of Electrical and Electronics Engineers
infrared - signals requiring direct line of sight (blocked by solid objects)
radio - signals that travel through solid objects
RF - radio frequency
roaming - user can maintain connection while moving from one wireless zone to another wireless zone
wireless card (PC card client adaptor) - radio transceiver network card that fits into the PC slot on notebook computers - also available as a PCI card for desktops or via the USB port
Helpful Resources: ***
recommended resources (more stars is better)
***** "The Unwired Classroom" by Jamie McKenzie http://www.fno.org/jan01/wireless.html
***** "The Role of Wireless Computing Technology in the Design of Schools" by Prakash Nair http://www.edfacilities.org/pubs/wirelessII.pdf
****"Just in Time Technology: Doing Better with Fewer" by Jamie McKenzie http://fno.org/sum02/jitt.html
Health & Safety Focus:
*** Cisco - Spread Spectrum Radios and RF Safety - White Paper
*** Enterasys - Health and Safety - White Paper
** Enterasys - Security - White Paper
The Unofficial 802.11 Security Web Page http://www.drizzle.com/~aboba/IEEE/
IEEE 802.11 Wireless Local Area Networks http://grouper.ieee.org/groups/802/11/
The IEEE 802.1 Working Group http://grouper.ieee.org/groups/802/1/
** Apple http://www.apple.com/airport/
** Cisco http://www.cisco.com/en/US/products/hw/wireless/index.html
** D-Link http://www.dlink.com.au/products/wireless/
** Enterasys http://www.enterasys.com/roamabout/
** Intermec (choose Products - Wireless) http://home.intermec.com/eprise/main/Intermec/Content/home
** Lucent Technologies http://www.agere.com/client/wlan.html
Stewart Fist - weekly communications column in the Tuesday edition of "The Australian" newspaper
14. Site Credits: This site is to help the 80% of people who just want learning, information and communication technology to be easy to use and reliable. To maintain fast access I have only included two low resolution photos. I designed the 370 byte (less than 1 k) animated radio beacon using Photoshop and GifBuilder. As the information changes rapidly a portable document format (PDF) version is not provided - please email me if you need more specific information or higher resolution photos. Feedback from Bryn Jones, Mike Leishman, Jim Fuller, Ian Gaynor, Steve Donatti, Peter Dwyer, Tony Crewe and Don Berry has been included on this site. Bruce Jenkins, Ross Smith, Chris Marley, Justin Cantrell, Stewart Fist, Michael Caddy, David Porter, Prakash Nair and Alan Wills have also provided assistance and information. Please take the trouble to offer ideas or suggestions - you will be acknowledged and others can benefit. The site is intended to be free of bias and receives no commercial gain from any party. Currently up to 300 people per week visit this site. Statistics on usage of this site are gathered by Google Analytics and Chillitech web stats. First published online in January 2001. Portions of this work may be used by others under the fair dealing provisions of the Copyright Act. The complete site should not be included on another website or in email. Please hyperlink to the current version at http://www.zardec.net.au/keith/wireless.htm or request permission for other situations via email.
are checked and this information is updated regularly based on feedback, published
articles, new experience, Internet research and new products)
(please note: while the experience of many educators has been included in my personal summary it is not intended to represent the opinion of my employer)