Category: Wireless Networking

Articles

News articles

Ozmo’s WiFi PAN available Q4, is this the end of Bluetooth’s reign of terror? – Engadget

From the horse’s mouth

Ozmo Devices Announces Revolutionary Solution Powering World’s First Wi-Fi Mouse and Keyboard

Related Articles in this site

The Wi-Fi Personal Area Network is getting closer

Ultra-Low-Power Wireless Networking

My comments and questions

Previously I have covered the topic of WiFi technology being used as a “personal area network” for a computer, which comprises of peripheral devices like mice and keyboards communicating to a particular computer via the WiFi technology. rather than that technology being used to transfer data between computers and other devices in a local area network. What has happened is that Ozmo have come up with a real chipset for use in these devices that can use this medium as well as run for a  long time on batteries. At the same time, Ozmo had built reference designs of wireless mice and keyboards that use this technology to communicate with their host devices.

One main question that I have about Ozmo’s effort is whether the same technology can be applied to devices that link directly to a Wi-Fi local area network’s access point rather than a particular computer? One main application that I see here with this technology would be Wi-Fi as a sensor / control network medium with devices like those that Ekahau had made as part of their Wi-Fi-driven real-time location technology, such as the pager tag which I had talked about in this site previously. Another application would be Internet radios, Wi-Fi-connected speakers and similar multimedia terminals that would be able to work on batteries as well as digital cameras that can upload to network storage or Internet sites or present to DLNA terminals without a severe penalty on battery life.

Another issue would be for a dedicated-function device like a set-top box or games console to support this kind of technology, whether as part of integrated Wi-Fi LAN functionality or as a Wi-Fi PAN setup as an alternative to Bluetooth or infra-red as a way of connecting peripherals, especially control peripherals.

It would be very interesting to see what comes of this technology once the silicon becomes fully available.

Introduction

Over this last few weeks, there has been hysterical media and political activity in Europe and Australia concerning Google’s Street View activities. This activity has become focused on the collection of Wi-Fi network data by the Street Survey vehicles which grab the initial street images.

The hysteria focused on identifying details about Internet use and Wi-Fi devices that existed at individuals’ addresses and that this data could be used to spy on individuals.

The truth

Wi-Fi site surveys are a part of Wi-Fi networking life

The Wi-Fi site survey is associated with nefarious activities like wardriving but it is commonly practised as part of Wi-Fi network use.

When you want to connect to your Wi-Fi wireless network with a client device, you will come to a point in the device’s setup operation where you see a list of SSIDs, then you choose the SSID that you wish to connect to. This is an elementary form of a site survey.

This is extended to technology enthusiasts like myself who activate Wi-Fi network scanning functions on smartphones to see a list of wireless networks operating in the neighbourhood that they are in for curiosity’s sake. Here, we see the list of SSIDs and an icon beside each SSID that indicates whether the network is protected or not. The practice also extends to use of “Wi-Fi-finder” devices to look for open Wi-Fi networks.

Similarly, people who are optimising wireless networks will use software like inSSIDer (which I have reviewed) or HeatMapper for site surveys and wireless-network optimisation. This software can also yield information about the BSSID and operating channel for that particular SSID and more sophisticated versions can use spectrum analysers to determine interfering frequencies or determine the location using support for GPS modules.

This leads me to Navizon and Skyhook Wireless who have done these surveys in order to turn these beacons in to a location tool in a similar manner to GPS or mobile-phone-tower-based positioning. The most common application of this is the Apple iPhone platform which uses this information for locating the phone during setup, avoiding the need for users to determine their time zone or location.

What does my Wi-Fi network yield

A normally-setup wireless access point or router will send out a “beacon” with contains the following data:

• SSID or ESSID which is the wireless network name
• BSSID which is the MAC address for the access point’s radio transceiver. This MAC address does not have any relationship to the Ethernet MAC address or the broadband (WAN) interface’s MAC address on your wireless router.
• Information required to determine security protocol to establish a successful conection

This data that is in this “beacon” is publicly available in a similar context to the information written on a vehicle’s registration label which would have the registration number (written on the number plates / license plates) and the VIN (vehicle identification number) for that vehicle.

It is also worth knowing that all access points and wireless routers have the option to turn off SSID broadcast. Here, you don’t have the SSID made available but have the network listed as a “hidden network” on some devices. This is something you can do in your router’s or access point’s Web-based management interface

When your network client devices are active in your wireless network and are “talking” to your wireless access point or router, they don’t broadcast an SSID or other beacon because they have “latched on” to that access point or router. This data will usually be encrypeted as part of the WPA security protocols that should be in place on your private wireless network.

Conclusion

Once you know how the Wi-Fi network works, you should then know that a site-survey operation should not gather the actual data that is moved across the network.

There have been some significant advances in Windows 7 that benefit the small business and the mobile laptop users. This includes people who use their computers for both their work use and home / community use.

Location Aware Printing for “work-home” laptops

If you run Windows 7 Professional or above on your laptop, this operating system has another feature to support the “work-home” laptop. It is in the form of “Location Aware Printing” where the default printer is determined based on which network the computer is connected to. The network can be determined by factors like the domain Windows is associated with, the SSID of a wireless network or the MAC of the Internet Gateway or DHCP Server that it gets its IP address from.

The printer can be a network printer that exists on the network like the HP OfficeJet at your workplace or your Epson WiFi-enabled all-in-one at home, a locally-connected printer like your Canon portable USB printer or a software-based virtual printer like your fax software’s “print-to-fax” function or “print-to-PDF” software.

At the moment, there isn’t ready support for handling location-aware printing in locations where there are many printers in the same facility, such as the typical workplace or educational institution with its many rooms.

Inherent support for mobile broadband services

Windows 7 has inherent support for 3G wireless broadband services thus eliminating the need to run operator-provided software to use the 3G modem. It also caters for laptops that have integrated 3G modems, which is a feature becoming more common with units that are supplied through mobile-phone outlets. In some cases, you may not need to install any software provided by the 3G provider to use wireless broadband Internet service.

This is similar to when Microsoft implemented Dial Up Networking in Windows 95 and users didn’t have to run any other software to get online with their dial-up Internet service.

Wi-Fi Wireless Flexibility for the business partner and hotspot surfer

Windows 7 has improved the Wi-Fi wireless infrastructure thus allowing a Wi-Fi equipped computer with an appropriate hardware driver for its wireless card to do more tricks. It can become a wireless-wireless LAN bridge which can allow for such things as running Wi-Fi devices that can’t go beyond regular WPA2-PSK authentication and don’t have an easy-to-use Web browser with networks that implement WPA2-Enterprise authentication at workplaces or Web-based authentication at hotspots. A good use for this could be for a business partner to take pictures with his Wi-Fi digital camera and upload them to his laptop or a site worker who wants to play his Roberts Stream 202 Internet radio at a wireless hotspot just by using his laptop (which will alert him to new work) as a gateway. It can also allow for “bonding” of multiple Wi-Fi signals for greater throughput, which can come in handy with multi-access-point networks.

Improved business network functionality

The Windows 7 Professional or Ultimate computer has improved business network functionality, which can come in handy with corporate or business-partner networks. One feature that I like is “network-specific” security that accounts for VPN and DirectAccess network setups. Here, you can set up a “domain-driven” business network profile for the VPN tunnel while you have a “private-network” security rule that applies to your home network or a “public-network” security rule that applies to public networks like wireless hotspots. This still allows business-driven network tools like system management tools or desktop-based MIS “dashboards” to operate “through the tunnel” with your computer being secure enough for the network you are in.

Speaking of DirectAccess, this is an improved IPv6-IPSec VPN replacement provided with Windows 7 Ultimate that does away with the need for extra weight associated with a lot of VPN software. The software sets up a separate IPv6 path to the DirectAccess server that your employer or business partner provides and makes the access to business resources more transparent. This function will require the use of a Windows Server 2008 R2 box installed at the workplace by your employer or IT contractor and your computer to run Windows 7 Ultimate.

Conclusion

This series of Windows 7 articles shows how your Windows-based computer and network can be improved when you deploy Windows 7.

I have tried to connect my Nokia N85 mobile phone and a Kogan Internet radio (which is on loan for an upcoming review) with a 2007-era Draytek VPN-endpoint router used as our household’s Internet “edge”. But what would happen is that I would supply the correct WPA-PSK passphrase and it would not admit the device. It would admit Apple MacOS X and iPhone equipment as well as Windows computers without a hitch. The problem was that the router was on a WEP-WPA compatibility mode which you may have set up for when not many embedded WiFi network clients supported WPA out-of-the-box.

A good idea would be to make sure your router operates in WPA security mode. This is to make sure all your WPA clients associate properly and quickly when you give them the WPA-PSK passphrase and your network is also secure to the full extent of the WPA standard.

Introduction

Now that the 802.11n high-bandwidth wireless-network standard has been declared a final standard, the price of 802.11n-compatible wireless-network hardware will come down to more affordable levels. This will lead to you considering upgrading your wireless network to 802.11n whenever the time is right to renew your home-network IT hardware.

The 802.11n access point

This works in a different manner to the 802.11a/b/g access points we are so used to. Basically, these units use a “multiple in, multiple out” methodology with “front-end diversity”. They will typically have two or three aerials with each aerial serving a particular transceiver. Some units may have an aerial serving a receiver as well as the two aerials serving two transceivers. It is totally different from “antenna diversity” which is used on most 802.11b/g routers and access points, where one transceiver works with two aerials, choosing whichever has the best signal strength.

These access points and the network client devices that connect to them also make use of “constructive multipath” to improve their quality of reception.This is different from the “destructive multipath” often experienced with FM radio and analogue television. Here, signals picked up as reflected signals are mixed with signals received by line-of-sight and “worked out” as a data stream.

The premium-priced 802.11n access points will be typically dual-band in which they can work on the existing 2.4GHz band or the newer 5GHz band. Some of this equipment may be able to work on both bands, as though there are two access points in one box.

Access Point Types

Single Band

These access points use a single access point that is set up to work on one band, typically 2.4GHz, but some of them work on 5GHz as an “add-on” access point.

Dual Band, Single Radio

These access points are like a single-band access point but can be set by the user to work on either 2.4GHz or 5GHz, but not both of the bands.

Dual Band, Dual Radio

These access points, sometimes described as “simultaneous dual-band”, are effectively two 802.11n access points in one box with one working on 2.4GHz and the other working on 5GHz.

Access Point Operating Modes

Primary Operating Modes

A typical 802.11n access point can be configured to work in one of two primary operating modes – a “compatibility” mode or an “N-only” mode.

Compatibility Mode

This mode, known as Mixed Mode or G-compatible mode allows 802.11g wireless network hardware to work from the same access point alongside 802.11n equipment. The limitation with this mode is that the wireless network works to a “worst-case” scenario with throughput that doesn’t hit the standards for an 802.11n segment. You will still have the larger coverage and service reliability with the 802.11n equipment and this benefit may pass through to 802.11g equipment

N-only Mode

This mode allows the access point to work only with 802.11n equipment and gives the equipment full wireless throughput as well as the full reliability of the standard.

Wideband vs Standard Channels

802.11n access points can run their channels as either “standard” 20MHz channels or 40MHz wideband channels which can yield higher throughput. The wideband channels also make use of a “standard” channel as a “base” channel for the double-width channel.

The preferred method of operation is that a 2.4GHz access point works on “standard” channels and most such access points will be set to have this kind of behaviour by default. But you can run these access points on the wideband channels with the limitation of poorer compatibility with 802.11g devices. If you are running a 2,4GHz access point in a manner to be compatible with regular 802.11g devices, it would be a good idea to stick to “standard” channels. If you are running 5GHz access points, you can get away with using the wideband channels and I would prefer setting up a 5GHz 802.11n extended-service-set to work this way.

The number of streams a device can handle

An 802.11n wireless device will typically be rated as being a single-stream, dual-stream or multiple-stream device. This relates to how many streams of data the wireless device can handle. All Wireless-N (802.11n) access points and routers will typically be either a dual-stream type or a multiple-stream type in the case of premium devices. Similarly, laptops with integrated Wireless-N capability; and add-on Wireless-N products will typically be dual-stream devices.

The main class of devices that will handle only one stream will be primarily-battery-powered devices like smartphones, WiFi VoIP phones, and WiFi-enabled digital cameras / portable media players because the single-stream ability won’t be intensive on these devices’ internal battery resources. Similarly, the idea of a single-stream Wireless-N network interface will also appeal to applications where size or cost do matter.

Other points to know

Best practice with dual-band equipment

If you are running dual-band equipment, especially dual-band dual-radio equipment, it would be a good idea to use the 5GHz band as N-only mode, while 2.4GHz works as compatibility mode. If you are running dual-band single-radio equipment, you will need to use older 2.4GHz equipment to run an 802.11g service set with the dual-band single-radio equipment on 5GHz N-only mode.

Use of aftermarket antennas

You can use external aftermarket antennas (aerials) with 802.11n equipment as long as all of the antennas are of the same type. This may work well if you replace the omnidirectional whip aerials with stronger omnidirectional ones. Then you may have to space the aerials further apart for the front-end diversity to work properly The main difficulty you will have is using directional aerials, in which case you may need to look for directional aerials optimised for 802.11n setups.

As well, if you are running dual-band dual-radio equipment, you will have to use antennas that can work on the 2.4GHz and 5GHz bands rather than antennas optimised for the 2.4GHz bands.

Shaping your 802.11n wireless network – the ideal upgrade path for your wireless network

I will be talking of WiFi networks that work on a particular technology and with a unique SSID and security parameter set as an “extended-service-set”. This allows me to cover setups where there are multiple access points working with a particular configuration.

You may be tempted to construct a multiple-access-point extended-service-set with an 802.11g access point and an 802.11n access point working in “compatibility mode” connected by an Ethernet or HomePlug wired backbone. The simple answer is "don’t”. You will end up with your wireless network having reliability problems especially as devices roam between the different access points and switch operating modes.

The simple answer would be to run different extended-service-sets with at least one access point for each WiFi technology. They are set up with different ESSIDs (such as SSID for the G cloud and SSID-N for the N cloud) with the wireless stations choosing between the different ESSIDs. The only thing they can have that is common is the WPA security parameters, and a common wired backbone which can be Gigabit Ethernet or HomePlug AV.

This could be achieved through deploying an existing 802.11g router that is set up as an access point and working on “SSID-G” and one channel while a newer 802.11n router working as the Internet “edge” is set to “N-only: or “compatibility” mode in the case of a single-band 2.4GHz unit, and set to “SSID-N” and a different channel.

As you evolve your wireless network, you may want to work towards establishing a 2.4GHz 802.11n “compatibility-mode” extended-service-set and a 5GHz N-only extended-service-set. You then upgrade your portable computers to work with dual-band 802.11n network interfaces or add dual-band 802.11n network adaptors to your existing equipment. The 5GHz extended-service-set will come in handy for high-throughput activity like video streaming and related applications while the 2.4GHz extended service set can work well with voice applications, smartphones, Internet radio and similar applications where throughput doesn’t matter.

If you are upgrading a wireless hotspot to 802.11n, it would be preferable to make sure your hotspot’s extended-service-set is on the 2.4GHz band and operating in “compatibility” mode so that customers can still use their existing 802.11g hardware on the wireless hotspot.

Some issues may occur with dual-band networks where the 5GHz extended-service-set may not cover the same area as the 2.4GHz extended-service-set. This is because the 5GHz band is of a higher frequency and shorter wavelength than the 2.4GHz band and is best demonstrated by AM radio stations being receivable at a longer distance compared to FM radio stations. It can be rectified by deploying a dual-band single-radio access point working on the 5GHz band in to the 5GHz extended-service-set as an infill access point.

Conclusion

Once you understand the 802.11n wireless standard and what it can and cannot do, you can make sure that you get the best out of the new standard while gaining the maximum mileage out of the existing wireless-network hardware.

IEEE finally approves 802.11n | The Register (UK)

802.11n: Ratified at last | Wi-Fi Planet

IEEE Ratifies 802.11n | WiFi Networking News

The Fine Points of Optional Wi-Fi 802.11n Certification | Wi-Fi Networking News

My Comments On This Evolution Of The Standard

Ever since 802.11n came about as a wireless standard, the equipment that was working to the standard was working to a draft version of the standard. This may have been acceptable for networks which weren’t critical to a business’s operations, because of the doubt associated with last-minute changes that could affect hardware compatibility. In some cases, this could also mean that an 802.11n segment may not work properly unless the equipment was based on the same chipset.

Now that the standard is final, enterprises can become confident about deploying 802.11n wireless network segments with cost-effective heterogenous equipment setups. As well, the cost of establishing an 802.11n wireless-network segment will reduce now that manufacturers can confidently sell more equipment at varying price ranges.

Existing 802.11n draft-standard segments

But what does this mean for networks based around existing 802.11n draft-standard hardware? Could they work properly with final-standard hardware with as much as draft-standard hardware being “flashed” to final-standard specifications. The compatibility issue raised in this question has been through the new revisions being declared optional rather than mandatory.

Support for single-stream 802.11n devices

The most popular benefit of the new standard would be the ability to support single-stream 802.11n station devices. This concept allows a device to have one transceiver rather than the two or three that is part of the standard. It is mainly brought about because of a need to have battery-operated devices like smartphones and VoIP WiFi handsets as part of the 802.11n wireless network and the single-stream 802.11n network adaptors can fulfil this need without draining the device’s battery too quickly.

The access points can provide full bandwidth to these single-stream devices without forfeiting bandwidth to other devices simply through the use of one dedicated stream for each of the devices. It then may be like providing the wireless equivalent of a “switched” Ethernet connection or ADSL-based broadband connection to this class of devices.

This factor has been improved with the ability for access points to be tested for three streams. This may allow for access points and routers to be differentiated on wireless-network performance levels as well as functionality levels.

Conclusion

The goal has been achieved for 802.11n to be a real wireless-network standard that complements the high-throughput Internet services and the multimedia networks of today.

 SmallNetBuilder – Small Network Help – 802.11n Headed for September Ratification

Cited text from SmallNetBuilder article

SmallNetBuilder has learned from a reliable source that the final issues in 802.11n have been resolved in this week’s meeting of the IEEE TGn in Montreal.

The draft standard is now expected to successfully pass through the final steps required for a ratification as a final standard in September. This is four months earlier than the currently published January 2010 date.

The key issue holding up the standard has been the mechanisms to be used to prevent interference between 802.11n and Bluetooth devices.

My Comments on this stage for 802.11n

Once this standard is ratified, most of us can now buy 802.11n-compliant wireless-network hardware while being sure it will work with other manufacturers’ equipment.

But the main issue with this ratification is whether most hardware manufacturers will roll out firmware for existing draft-specification 802.11n hardware that is in the field. This is of importance whenever newer final-specification hardware is deployed, because there could be compatibility issues between the different versions of the standard.

A good step to go about this is to go to manufacturers’ Websites and look for upgrade packages for any 802.11n hardware. In the case of laptops, use the laptop manufacturer’s Website or “quick-update” routine to check for updates for the wireless-network subsystem. If you run an “n-box” or other equipment serviced by your Internet service provider, check with the provider if there is new firmware in the pipeline for the hardware. This may be dependent on whether the device’s manufacturer is rolling out compatible firmware for provider-distributed devices.

In some cases, you may need to run your 802.11n wireless network segment on a “mixed” setup which observes best compatibility with 802.11g devices even if the segment is running only with “n” devices.