How to: Define Wireless Network Requirements
August 22, 2008
The first step in implementing a wireless network is defining the network's requirements. In this tutorial, Wi-Fi expert Jim Geier offers guidance on how to identify valid requirements.
Requirements define what a wireless network must do, which provides the foundation for the design. Requirements for a wireless network include needs, such as signal coverage in elevators and support for voice telephony. Leave the technical details, such as specific technologies (such as 2.4GHz vs. 5GHz 802.11n), components, and configuration settings to the designers after all requirements are well-defined and agreed upon.
Requirements to consider
Before implementing a wireless network, consider the following types of requirements:· Applications. Ultimately, the wireless network must support user applications, so be sure to fully define them in the requirements. They could be general office applications, such as Web browsing, e-mail, and file transfer, or they could be wireless patient monitoring in a hospital or voice telephony in a warehouse. Be as specific as possible. The application requirements enable designers to specify applicable throughput, technologies, and products when designing the system. · Environment. Provide a description of the environment where the wireless network will operate. For buildings, include the floor plan, type of construction, and possible locations for mounting access points. For outdoor areas, include satellite images, aerial photographs, or drawings. Walk through the areas to verify accuracy of these items. Take lots of photos. In addition to a visible inspection, consider performing an RF site survey. All of this will capture the environment in a way that will help designers choose the right technical elements. · Coverage areas. This describes where users will need access to the wireless network. They might only need connectivity in their offices and conference rooms, but they may also need connectivity inside power utility rooms and the cafeteria. Also, carefully think about whether coverage is needed in stairwells, elevators, and parking garages. These are difficult-to-cover areas and can drive the cost of the wireless network very high. By properly specifying coverage areas, youll avoid the unnecessary expense of installing access points where theyre not needed. Unless obvious, also identify the country where the wireless network will operate. This impacts channel planning and product availability. · End users. Be sure to identify whether users are mobile or stationary, which provides a basis for including enhanced roaming in the design. Mobile users will move about the facility and possibly roam across IP domains, creating a need to manage IP addresses dynamically. Some users, however, may be stationary, such as those using wireless desktops.
After defining these elements, you should have enough information to design the solution. Before proceeding, though, ensure you have consensus from all stakeholders, such as executives, users, and the operational support organization. If requirements are not clear enough, you should do some prototyping or pilot testing to fully understand requirements before spending money on the design and installation.
- For more tutorials by Jim Geier, read "Troubleshooting 802.1x Missing Supplicant Problems (Part I)," "Minimize WLAN Interference," and "Troubleshooting 802.1x Port-Based Authentication Systems."
Jim Geier provides independent consulting services and training to companies developing and deploying wireless networks for enterprises and municipalities. He is the author of a dozen books on wireless topics.