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Best Practices in Planning Your Wireless Network

Laying out a wireless network can be tedious, and sometimes downright stressful. In multi-AP deployments (i.e. every enterprise deployment) the placement of one AP affects all others, so every tweak in AP positioning can be like bumping the first domino, causing the entire chain to fall and have to be set up again. That is why, when mapping out where to place APs and how many to use, it’s important to have a blueprint before taking on the task yourself.

This can be done in two fashions: automatically and manually. Both practices are relatively easy for wireless pros, but each has its strengths and weaknesses. When mapping out a network across multiple stories, or large open buildings like warehouses, it is best to automatically plan AP placement using a downloaded 3D map of your space and software specifically designed for this task, like Ekahau Site Survey. On the other hand, when planning out smaller networks, often times professionals find more satisfaction, and more control, in doing so manually.

We’ve outlined both best practices below, as well as next steps to follow to ensure that your network keeps running at peak performance.

Automatic Network Planning
For the less technical wireless professional, or for large scale deployments, automatic network planning software is the best way to map out where APs should be placed to optimize your network’s performance and the overall user experience. This process involves importing floor plans of the areas to be covered by the wireless network, specifying some key dimensions on the floor plan (so the program can determine the scale accurately), specifying key construction elements in your floor plan (wood vs. metal studs, wall materials, other structures not represented in the floor plan, etc.), and selecting the AP make(s) and model(s) you plan to deploy. Most software includes a database of AP features and capabilities for common manufacturers and model numbers, so it tries to do the very best job to maximize the potential of the equipment you plan to use. The software will then calculate the approximate locations and configurations for the APs on a virtual 3D map of your building. It will also provide a channel map (a channel assignment for each AP), making every effort to avoid co-channel interference between APs. Once the software has developed a proposed layout, you can make manual adjustments, for example, if some APs end up being located in undesirable or infeasible locations (no power, no network drop, etc.). This is where the real value comes in, because in an actual deployment a few tweaks like this causes the domino effect, but since you’re only dealing with software right now you can see the effect your manual change has without needing to do any other work.

You can also play “what if” with the software, trying different configuration parameters than those recommended, or even “trying out” equipment from different manufacturers to see if certain solutions have advantages over others. For a large deployment, the time savings with an automated approach are tremendous, and easily justify the cost of either the software purchase, or the services of a third-party to run the simulations for you.

Once you’re pretty confident of your deployment, you can lay out the network, and again leverage the software to perform a site survey, taking measurements at locations within the deployment to assess the accuracy of the original software layout and make other small adjustments to ensure the best WLAN configuration.

Manual Network Planning
This approach is better suited to the more seasoned wireless expert, and is typically best for smaller deployments. It still requires the use of software – any deployment of more than just a few APs has far too many variables to manage the entire process manually. Manual network planning is only “manual” in the sense that you place your APs on the building map yourself, possibly even choosing the channel layout yourself, and then letting the program calculate overall WLAN coverage, providing a “heat map” of expected signal strengths at all locations in the network, so you can see if your layout is acceptable before actually deploying any equipment. This approach is most often used when your choices for AP placement are limited. The software can optimize the AP settings to maximize overall performance based on your AP placement constraints. After you’ve settled on a design, the same site survey described above should be used to validate both the placement and the settings, with necessary adjustments being made along the way.

Ongoing Monitoring and Analysis
Once a network is up and running you need a different solution to perform day-to-day network monitoring and analysis. Monitoring solutions are used to track which stations are connected to which APs, the overall throughput each station is able to achieve, signal strength and noise measurements, and network problems like packet loss, latency, and device configuration issues. When problems are identified, you need to be able to drill down to the details of each station to AP connection, often down to the packet level, to determine the root cause of problems.

Using a combination of WLAN planning software and a WLAN monitoring and analysis solution, you will be ensured of both the best overall WLAN design possible, and well as a network that continually meets the demands of your ever-expanding wireless network user base, essentially eliminating the threat of one day toppling over all those WLAN dominos.

Let’s Start Transferring to 802.11n

The 802.11n protocol vastly improves upon previous 802.11 standards by giving the user the capability to provide voice and video over IP using Wi-Fi. It also allows for denser coverage across many different applications because with its much greater throughput, 802.11n can service many more users per AP.

Given these benefits, it is likely that any upgrade to 11n will involve a significant WLAN redesign, so it is very important to look at the entire lifecycle for developing and expanding your WLAN. Listed below are the three major phases for implementing and updating your 802.11n system so that it will reach its full potential.

Phase 1: Network Design and Requirements
When designing your WLAN there are four key areas to address before you even consider any hardware purchases.

1. Define the applications that users are going to expect to access via Wi-Fi. Pay attention not just to the type of application, but also the data loads and  expected response times, and pay particular attention to applications that use real-time protocols like VoIP or Video over IP which require priority routing over Wi-Fi using QoS (quality of service).

2. Think about where you want to place your access points and the type of environment they’ll be located in – office space, warehouse, retail, etc. Will they be sealed or inconspicuous? Also, assess the “background noise” in your environment within the frequency range you expect to use.

3. How will your physical layout and networking needs affect the type of equipment you’ll need? Thin APs with a central controller or stand-alone APs that interoperate with each other? Traditional multi-channel cell layout or a managed single channel deployment? Your physical layout may dictate the need for directional antennas in some areas, like building corners, where you’d like to contain your WLAN delivery within your physical space and benefit from the added range of a directional antenna.

4. Use a WLAN planning tool to translate your requirements into a proposed hardware layout and design. As WLAN networks grow, deploying APs by the seat of your pants is no longer an option. WLAN planning tools do an excellent job proposing AP placement as well as recommending specific AP hardware that may be needed to meet your unique requirements. If you have an existing WLAN, use the planning tool to verify your current network coverage and performance before planning any expansion.

Phase 2: Deployment and Verification
Once you’ve designed your network and deployed your new hardware, you need to verify whether your setup matches what you originally specified. Again, your WLAN planning tool can be used, this time to perform a site survey of what you’ve deployed to compare with your design. Here’s a really quick checklist to help you take all factors into account:

• Ensure coverage
• Verify performance (network throughput)
• Check and correct AP configurations
• Test end-to-end network operation

Once this is complete, you will have an accurate picture of how well your actual deployment meets your requirements, and you will have the data you need to make any modifications.

Phase 3: Management, Troubleshooting, and Expansion
Now we have the most important phase of all, dealing with the day-to-day issues of active users on your WLAN. This requires proactive management, the ability to troubleshoot your distributed WLAN network, and the capability to easily expand your WLAN as demand grows and new applications are introduced. Management requires software with simple dashboard views that show you the current status of your network and provide alerts when your design parameters are violated. Troubleshooting requires the ability to sniff packets anywhere in your wireless network for detailed protocol analysis. You can typically find a single software solution that meets both these needs.  For expansion, you can return to your trusty WLAN planning software, which already includes your current design, and do a little “what if” to see how network expansion can address the growing demand that is sure to come from such a robust, well designed, and well managed WLAN!