|
By Anne Marshall & Joel Brooks
Illustration: Johnny Ueland
 FROM THE HOME OFFICE TO LARGE CORPORATIONS, MORE PEOPLE ARE HOOKING UP TO WIRELESS NETWORKS. HERE'S HOW TO GET THE MOST FROM YOURS
Barb and Alex are on their deck, and it's a beautiful Saturday morning. They are sipping their morning cappuccinos and planning their next vacation. "So, Costa Rica, the last week in January?" Alex asks, and Barb replies, "That looks fine on my calendar. I'll book it into the departmental agenda right now." Perhaps you're envisioning brochures, travel sections from weekend papers and a thick daytimer? If so, think again — think laptops. The couple is amongst a growing number of North American professionals who are researching and coordinating schedules online — amongst many other functions, at home — thanks to the convenience of a wireless local area network.
Alex learned about WLANs at a local home-electronics store a few months ago when he was setting up his home office. He was looking for some basic networking capabilities as Alex wanted to share the single high-speed Internet connection and printer between his new office in the basement and his wife's desktop in the bedroom upstairs. While surveying the selection of small routers, Alex came across a wireless one and started asking questions. At the end of the shopping trip, he had a wireless router and a wireless card for his PC and set up his network, which was operational within hours. A few weeks later, Barb was issued a new laptop at work, and it too had a wireless card in it. With a little help from her company's IT department, she too is happily using their home network.
WLANs are gaining in popularity and are pervasive in a multitude of situations — from the home office to large enterprises. Easy to install and extremely attractive in environments where wiring is expensive or inconvenient, these networks are projected to proliferate within the next few years. It is estimated that spending on them in the US is likely to grow to more than US$5.2 billion by 2005 from US$1.7 billion in 2002 and US$1.1 billion in 2000. Understanding the total cost of ownership and the choices within the area can help ensure that you get the most from your WLAN, while mitigating security and financial risk. Here is the information Barb and Alex gathered before implementing their WLAN.
What's a WLAN: A wireless local area network allows communication across a local area network via high-frequency radio waves, eliminating the need for a wired Ethernet connection.
But not all WLANs are created equal. The protocol that has been approved by the Institute of Electrical and Electronics Engineers (more commonly recognized as IEEE) is also referred to as 802.1x and has several extensions or standards. The most widely implemented to date and the most popular for home use is 802.11b — also known as Wi-Fi. However, there are other standards that operate at different frequencies and have different maximum transmission rates. (For a comparison of standards, see Table A)
| TABLE A |
COMMON WI-FI STANDARDS |
Standard |
802.11b |
802.11a |
802.11g |
|
Frequency |
2.4 GHz |
5.2 GHz |
2.4 GHz |
| Maximum transmission rate |
11 Mbps |
54 Mbps |
20+ Mbps |
| Typical use |
Small office / home office |
Limited implementation |
Enterprise level | |
Performance of 802.11b network: Using the same frequency band (2.4 GHz) as your microwave oven, devices using this protocol have a transmission range of approximately 100 metres at a maximum rate of 11 Mbps — which is comparable to the original LAN networks deployed 10 years ago. This transfer rate compares favorably with a high-speed Internet connection (downloads at 1 Mbps), but pales beside the top speeds of wired Ethernet LANs (at 100 Mbps or 1000 Mbps) that are the norm in most corporate networks — hence the popularity of this technology for small offices, home offices and for subsets of corporate networks.
Not all standards interoperate. Therefore, care needs to be taken to ensure that all components are the same standard (i.e., 802.11b) or testing performed to understand how well the components with different standards interoperate.
Required equipment: Regardless of the WLAN's location, the basic components within the implementation are much the same. Each device that will transmit wirelessly needs to contain a wireless capable component. For user devices, to date, this is most commonly a wireless card inserted into a laptop or connected to a desktop computer. Now there are computer chips that are wireless capable. An example of this is Intel's Centrino. The wireless component within the user device communicates with a wireless hub, router or access point that also contains a wireless card. In a home WLAN, the hub would typically be connected to the digital subscriber line or cable modem from the Internet service provider via an Ethernet cable. For larger implementations, the building blocks remain the same, with additional access points and bridges extending the reach and potentially some additional switching or firewall hardware to secure the wireless segment of the network.
The cost: Prices vary, but a basic wireless capable four port router can be purchased for about $150 and a PC wireless card for $130.
Security issues: Like any other computer system, and any other airborne transmission, WLANs are subject to compromise. In fact, ease of "sniffing" traffic on these networks has been highly publicized (commonly called war-driving) and is no doubt one of the main reasons why they have not taken off in a big way in the corporate world yet.
To ensure ease of setup, many WLAN equipment manufacturers ship devices with all security features turned off and set to broadcast (by virtue of their default settings) detailed information regarding how to connect to them. This information can be picked up and used by any compatible device within its broadcast range, effectively by-passing any physical security, such as walls and door locks, that would exist in a wired network. The most common types of abuse of unsecured WLANs include hijacking bandwidth, sniffing passwords, using the network to send spam, attacking computers and infecting them with back doors or Trojans.
However, easy steps can be taken to mitigate the risks. For detailed information on how to secure a WLAN, refer to the equipment documentation and the websites listed in Table B.
WLAN advantages: There is, of course, a convenience factor with wireless technology. Not having to be physically connected means people can be working places other than at their desks — like in meeting rooms. It is also an easy way to set up a training facility or a trade show exhibit or provide Internet access to visitors.
Clearly, using this technology in areas that are difficult and expensive to wire — such as large warehouses — can be cost effective. But one of the largest benefits has been documented in studies by such prominent research firms as Gartner Inc. The studies indicate that adding wireless capability to a mobile office worker's configuration can increase productivity by extending locations and amount of time workers are willing and able to work.
Limitations: Because WLANs transmit via airwaves, it's important to ensure that the signal is able to pass through or around physical barriers such as walls and floors. While most homes wouldn't pose an impenetrable barrier, modern office buildings can create a greater challenge due to the large amounts of metal and glass that are typically used in their construction. This makes a site inspection a critical component of the planning process. Then a knowledgeable estimate of the anticipated range and therefore the number of access points and bridges could be made. This planning phase should also incorporate an assessment of the security required on the WLAN, determining how it will fit in the overall network, including authentication and encryption mechanisms. And remember that since these frequencies are not licensed and are used for other things such as cordless phones, wireless A/V transmitters and microwave ovens, there can be unusual, intermittent and elusive problems to identify and resolve.
Accessing corporate networks: This should be considered in light of what corporate information is being accessed and what the company security policy is — which should be updated to explicitly define uses of WLANs. Most security experts recommend the use of a virtual private network (VPN) when accessing corporate information over the Internet. Except for any portion of the network that is intentionally left accessible to the public Internet, typically within a demilitarized zone (which is a computer or small subnetwork that sits between a trusted internal network, such as a corporate private LAN, and an untrusted external network, such as the public Internet). For example, Barb's company has a Web-based mail service that allows employees to access their e-mail by entering an authenticated user ID and password. She can access the financial reporting system remotely by using a VPN connection, which involves an additional password. But she is not allowed to perform administrative functions, such as purging archives, remotely.
These are easy to set up. Do you need to talk to your IT department/adviser before doing so?
This is analogous to asking, "Should you check with the accountants before you set up a new company bank account?" While these networks are easy to set up, they can create significant security vulnerabilities or cause performance anomalies across corporate networks if they are not implemented as part of the broader network plan — most notably when attached to a corporate wired network. No device should be connected to the corporate network without IT's awareness of it. Company policies should be reviewed and updated and users educated to ensure that risks and mitigation strategies are understood and implemented.
WLANs can be an outstanding way to build a home or small business network or supplement an enterprise network. But they can also represent a new and potentially significant financial and security exposure. Being well-informed about your choices will ensure that the investment you make in them, even if not large, is money well spent.
Over the next few years (or months) it may become virtually impossible to avoid this technology as new laptop computers that have built-in wireless networking capability and public access points ("hot-spots") pop up in more locations, such as airports, cafés, hotels, shopping malls and restaurants. Who knows, maybe one day you'll even be able to "WLAN" it in a kayak in Costa Rica.
Anne Marshall, CA•IT, and Joel Brooks are principals in fysty Inc., an IT consulting practice in Toronto | 
