Wireless Systems Design

Hot Spot In A Box: The Missing Wi-Fi Link Joins With Linux

A large gap exists in the wireless-product lines of most network-equipment manufacturers. That gap is one of needed functionality—in other words, access points that can be configured, monitored, and secured by standard network-management systems. A number of existing wireless-network devices are suitable for home, home-office, and small-office environments. Yet few of them meet the needs of the enterprise user.

One of the most compelling needs of enterprise networks is the capability to easily manage four, ten, or even a hundred wireless access points (APs). For a coffee-shop owner, logging into one access point using a browser isn't a problem. Yet having to do so for multiple devices would quickly swamp the limited resources of most IT departments.

Enterprises also tend to have additional security concerns. Physical cables can be secured in an armored conduit. Access to them can be guarded by locks and security guards. In contrast, radio waves respect no physical boundaries outside of Faraday cages.

Access points that provide the necessary functionality aren't necessarily different at the networking interface. But they must be profoundly different at the control interface. The only way to ensure manageable and secure networks is to have network devices support standard protocols and capabilities. Proprietary approaches are only as strong as a single company's capabilities. Yet standards are developed, tested, and supported by the entire networking world.

Standard support also opens up markets in the European Union and international telecommunication companies. They require single platforms to be deployable throughout the world. In addition, products that adhere to standards can be tested and deployed quickly by larger enterprises. They also can be integrated into existing network and security-management systems. A host of tools is available to automate the configuration, management, and securing of network devices. These tools support both network-management and security standards.

Essentially, enterprises are looking for "Hot Spots in a Box" that can be deployed quickly and—ideally—integrated automatically. To the network-equipment manufacturer, creating such an access point probably means a different or additional development effort. Until now, the emphasis has been on getting 802.11b, a, and g to work. Manufacturers also have focused on ramping up the effort to support WPA and 802.11x. Adding support for networking protocols like SNMP or security standards like RADIUS is probably not in the skill set of the teams that are currently developing wireless products. Similarly, this additional functionality may be missing from the standard-development libraries that are maintained by manufacturers.

Manufacturers are left with two choices: Develop the software internally or obtain it from outside sources. Pricing and market pressures argue against internal development. With the amount of engineering effort undeterminable along with the cost and time to market, the safest bet is to go to outside sources for the necessary libraries. But here, a designer runs into problems. Do the libraries exist to support the additions to the system? Will they run on the targeted hardware? Will they run with the existing software? What will their cost do to the pricing model?

The best alternative to either in-house development or buying off the shelf is open-source software. Several wireless manufacturers are using small versions of Linux. The most notable example is Linksys, which is using such Linux versions for the WRT54G, WAP55AG, and WVC11B (among others). There are three big advantages to this approach: First, little or no time is spent in development. Users just port the software to the hardware. Secondly, Linux can run on older hardware, which allows designers to choose from various, inexpensive hardware platforms. Lastly, it's free. Linux is released under the GNU public license. Its restrictions are explained at www.gnu.org/licenses/licenses.html.

No matter which development route a designer takes, the success of the new access point heavily depends on testing, integration, and documentation. For products to claim that they support standards, manufacturers must test to those standards and be ready to produce the testing results for prospective customers. The integration effort must ensure that the new products interface with the most popular network and security-management systems. Such documentation will be critical for customers, who want to extend their current management systems to include new equipment.

If it's done well, this extra effort will be repaid by bulk sales. These sales boast a higher margin and lower cost than single sales through retail outlets. Don't forget: Enterprises are willing to commit to and standardize on the manufacturer that has a product that solves their problems.

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