|
Written by OJ Jonasson
|
|
Tuesday, 06 November 2007 |
|
Network architects and administrators now have another option that can be far less costly and complex for network moves, adds and changes (MACs) with the advances in Wi-Fi technology. Rather than ordering up more CAT5 runs, network administrators can now install a wireless card in desktops (if not already equipped) and connect to the enterprise wirelessly. No cabling headaches, no location restrictions, no spare Ethernet ports in the switch to worry about nor the usual delays for related construction work. Just instant gratification. This not to suggest the wholesale replacement of your existing copper forest with wireless links. Rather, it’s an opportunity to make sensible use of the right link layer technology to satisfy the requirements of the MAC request, i.e. necessary bandwidth, security requirements, service delivery time, network reliability, temporary versus permanent, potential environmental factors such as building restrictions and, of course, cost. It’s not a matter of which technology is best, rather it’s making the right choice in the circumstance. Wi-Fi simply adds one more option for LAN connection. A major and complementing factor, 2005 was the first year that notebooks outpaced desktop shipments and virtually all notebooks today ship with 802.11 capability built in. Fortuitously, it is the notebook user that Wi-Fi appeals to since they are typically transient or mobile workers who need portability and network connectivity on the run. Access to the corporate network for e-mail, viewing the contents of personal folders, running applications as well as Internet access can all be securely delivered through a Wi-Fi link. While speed and distance have been an issue, the advent of 802.11n has helped overcome these limitations with distances now up to 70 meters and speeds up to 300 Mbps. Far and away a significant improvement over the older 802.11b distance and speed limitations of 35 meters and 11 Mbps. While the 802.11n is still in draft form, the Wi-Fi Alliance has certified more than 95 vendor products to the 802.11n Draft 2.0 level. An abundance of choices to satisfy even the most discerning buyer, i.e. the vendor biased versus the need for guaranteed interoperability. From the user perspective, Wi-Fi means freedom. Users are able to roam from their private offices to a conference room or even move from floor-to-floor without the need to log off the network – a very nice convenience and with a genuine productivity gain. For the enterprise Wi-Fi offers enhanced flexibility, increased worker productivity and improved customer service that can potentially lead to increased revenues. Wi-Fi is not just another wrench in the network admin’s tool box, it’s an option with major, tangible benefits across the entire enterprise. Some final words of advice: i.) be sure to properly architect and plan out your Wi-Fi network needs before any deployment; and ii.) utilize only Wi-Fi Alliance certified equipment that is industrial strength and . Contact the Author: OJ Jonasson, CMC, CISSP, CWSP, SCSE is an independent Information Technology expert. OJ can be reached by e-mail and his web site.
| |
|
|
|
Written by Jim Geier
|
|
Sunday, 14 October 2007 |
|
The spectrum regulatory body of each country restricts signal power levels of various frequencies to accommodate needs of users and avoid RF interference. Most countries deem 802.11 wireless LANs as license free. In order to qualify for license free operation, however, the radio devices must limit power levels to relatively low values.
Read more...
| |
|
|
|
Written by Shivkumar Jagannath
|
|
Wednesday, 26 September 2007 |
Ive finally managed to put it all together! I believe I have managed to build the ultimate embedded hotspot-in-a-box solution.
What
I have done is, put together Chillispot, FreeRadius and phpMyPrepaid on
the same box. While this itself is not unique, what separates this from
other such initiatives is that all of this comes on a 512MB Compact
Flash Disk.
The basic platform is a Soekris Engineering net4801
appliance. This has a decent 128MB of RAM and three Ethernet
Interfaces. More details on the Soekris box are here.
The
challenge was to look for a Linux distribution that recognised all the
hardware on the Soekris, and was small enough to fit on a CF Card. My
search lead me to Voyage Linux which is a debian derived distribution with a 66 MB footprint in its basic avatar.
Since
I didnt have a CF Card reader, I used my Nikon Coolpix n770 camera as
the reader. Attached it to my Ubuntu laptop and the card showed up as a
usb disk. Using the voyage installer was a trivial exercise. Once the
basic OS was installed, I then plugged the CF Card into the Soekris and
watched it boot beautifully over the serial console!!
Once this was done, I connected the Soekris to the Internet and ran apt-update to update the package list.
I then went about installing MySQL, PHP, Lighttpd (lighty) instead of Apache, FreeRadius, Chillispot and Phpmyprepaid.
After two days of fiddling around, I figured out why Chillispot wasnt working properly, rectified it (eth1 has to be 0.0.0.0).
I now have a full fledged hotspot controller which does not need to connect to any centralized Radius Server for authentication.
The Soekris box is currently undergoing burn-in.
The
only problem I am facing is that of MySQL tables crashing! I live in an
area where power outages are the norm. Thank you DLF for wonderful
buildings and crappy infrastructure.
High on my to-do list is change
over from MySQL to firebirdSQL (www.firebirdsql.org). Wonder how long
will it take to modify phpmyprepaid to work on firebirdsql...
For all your uber-geeks out there, I can send you a copy of the CF card image if you feel a little adventurous. #free -m reports
124 M Total 59M Used 64M Free
The total size of software on CF card is around 370 MB.
| |
|
|
|
Written by OJ Jonasson
|
|
Thursday, 06 September 2007 |
|
Trying to get my 4 different Windows boxes (1 - XP Pro/HP notebook, 1 - XP Home/ Dell tower, 1 - XP Home/Dell Inspiron notebook and 1 - Vista Ultimate/Acer Aspire Tower all interconnected with a D-Link DI624 wireless router) to work together, i.e. share printers, files & support Internet access was consuming enormous amounts of my time to no avail.
After spending days & weeks setting and re-setting dozens of Windows parameters and registry settings, some functions would seem to work and then suddenly, for no apparent reason, print sharing, file sharing or whatever would stop working. After months of effort and total frustration, I accidently discovered a product called "Network Magic" from Pure Networks Inc. that solved the majority of these problems. The product is not yet bulletproof as I still have occasional problems with file & printer sharing that seem to come and go - with a little fiddling it's restored to normal - clearly and far & away much better than without the product.
The product is competitively priced ($39 US) for three computers. As well they offer a trial or evaluation version to try before you buy. It has a collection of other very useful features and utilities. Accordingly, if you have a small, local network of Windows-based boxes and your not an MCSE, I highly recommend you give it a road test.
| |
|
|
|
