Review: Motorola LANPlanner (RF Management Suite, Part 2)

Motorola LANPlanner
www.motorola.com


Price: $12,000
Pros:   Wizards greatly simplify RF network design, easy prediction and visualization
Cons:   Somewhat awkward site survey, no work order or AP config generation


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As enterprises roll out 802.11n, most will make hefty infrastructure investments. Skilled carpenters always “measure twice, cut once.” This conventional wisdom also applies to WLANs, where poor planning so often leads to coverage gaps, disappointing performance, and costly retrofits.


 


Wireless networks pose unique design challenges. APs behave differently in each location because radio waves are reflected, scattered, and attenuated by the surrounding environment. One cannot accurately visualize signal propagation or quantify a building’s impact on WLAN quality of service without modeling tools.


 


Rules of thumb, like positioning APs to create circular cells with 20 percent overlap, take you only so far. In reality, those cells get flattened and distorted as transmissions are absorbed and bounced off of walls, doors, and people. On the other hand, surveys that painstakingly gather in-situ RF measurements are resource-intensive. In the end, no matter how extensive the site survey, sampling can still miss problem areas.


 


This is the impetus behind LANPlanner, a predictive WLAN design tool based on Wireless Valley RF modeling technology acquired by Motorola in 2005.


 


“Model, Design, Deploy, Maintain”


LANPlanner can be used to create 2D and 3D models of each target venue, using physical characteristics to calculate a site’s RF propagation behavior and impact on WLAN performance. When used prior to deployment, LANPlanner automates design tasks such as AP placement and channel assignment, generating a Bill of Materials to guide installation. After deployment, LANPlanner can verify real-world performance and predict the consequence of potential refinements.


 


We used LANPlanner to design two tiny WLANs to be managed with Motorola’s RF Management Suite (one shown below). These designs barely scratched the surface of LANPlanner’s RF modeling smarts, but they let us experience Motorola’s four-step “RF-intelligent design” process: Model, Design, Deploy, Maintain.


 


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Figure 2-1: Displaying a LANPlanner design’s sensor coverage. Click here for larger image.


 


To get started, we installed LANPlanner version 10.1.5 on a Windows XP laptop with a Cisco 802.11a/b/g adapter. Each license ($12,000) gives you the right to run this Win32 program on a single system (XP or 2000, but not yet Vista). An activated license is required, not just to create and edit designs, but also to view them. This made it harder to review our designs with others elsewhere—for that, we had to rely on printed reports.


 


You might be tempted to install LANPlanner on a beefy desktop with a nice big monitor, but we recommend spending your license on a laptop with a 32-bit PCMCIA slot. Why? You’ll want a mobile device with a Netgear WAG511v2 or Cisco AIR-CB21AG-A-K9 PC card to use LANPlanner’s site survey feature. LANPlanner comes with AirDefense drivers that must be applied when that card is installed, in lieu of manufacturer’s drivers. Alternatively, site survey licenses can be purchased separately ($2,500)—for example, to let remote office staff supply site readings to a central designer.


 


Wizard-based RF modeling


Predictive modeling tools can only do their job really well when given sound input, so invest in prep time before creating a LANPlanner project.


 


Gather building floor plans—preferably AutoCAD (dwg) files with embedded detail about building materials. If AutoCAD files don’t exist for a site, LANPlanner can import simple floor plan images (e.g., jpg, gif, bmp files), but then requires input to establish scale and describe walls and windows and other RF barriers on each floor.


 


Alternatively, LANPlanner can let you draw floor plans, but free-hand drawings won’t be as efficient or accurate. Our advice: do your homework and start a project with accurate building data; big shortcuts here diminish what you gain from using LANPlanner.


 


To create a new project, LANPlanner starts by presenting a list of available building materials, drawn from its extensive RF attenuation library. That list can be applied as-is or edited, but must include the major materials used by your site (or represented by layers in your AutoCAD file). Our designs used library defaults for common materials like drywall, wooden doors, glass windows, and concrete foundations.


 


After LANPlanner has this list, a Building Floor Manager wizard solicits input needed to generate a “3D intelligent RF map” for each floor in the building. For example, here we import a JPG floor plan and use the wizard to draw rooms and partitions on top of that background image (see figure 2-2).


 


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Figure 2-2: Drawing with the Building Floor Manager wizard. Click here for larger image.


 


Before drawing exterior walls, we selected “foundation” from the drop-down menu. When drawing interior walls, we chose “dry wall,” and so on. This task is a bit tedious, but it’s very straight-forward and fast—if you have the necessary data. Fortunately, those using AutoCAD files can skip this step—highly recommended for large sites.


 


After all floors have been formatted this way and scaled by drawing a line of known length, LANPlanner assembles the building by stacking floors (ordered by floor number). If floor plans are accurate and a good alignment point was selected, LANPlanner displays a 3D map that looks like your building (see figure 2-3). Eyeballing that 3D map from different angles gives you a chance to spot and correct basic mistakes before continuing to WLAN design.


 


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Figure 2-3: Assembling a Building.


 


Go to page 2.


 


 

Automated WLAN design


LANPlanner earns its keep by using per-site RF models to create WLAN designs that meet stated coverage and capacity requirements. Designs can be generated by adding APs manually or letting LANPlanner place APs where needed automatically. Most users should start with the latter, using manual adds, moves, and deletes to reflect necessary refinements (such as sliding proposed APs to more convenient mount points.)


 


Either way, design starts by selecting the kind(s) of AP to be deployed. Naturally, LANPlanner includes an extensive library of Motorola APs and requires no help to configure those AP’s capabilities or predict their default RF behaviors. It is also possible to define your own AP types to incorporate legacy devices in upgrade designs.


 


During automated design, a Quick Start AP Placement wizard asks for the maximum number of APs to be installed at this site, the type of air interface (802.11a or b/g) to be used, and whether redundant APs are required. Global settings determine max clients per AP, peak data rate, and any “fudge factor” to be subtracted for network overhead.


 


Next, the wizard lets you specify one or more “throughput regions.” These designated coverage areas are shapes, drawn on the 3D map, tied to peak data rate or minimum RSSI, number of clients, and average sustained data rate. The latter is easily specified by selecting one primary application from a pull-down list that includes Web surfing, videoconferencing, and VoIP (see figure 2-4). Regions can overlap to represent multi-use networks, but we did not see any ability to specify WMM priority.


 


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Figure 2-4: Automating WLAN design using Quick Start AP Placement. Click here for larger image.


 


“Exclusion regions” can also be defined–designated areas where APs should NOT be placed (or users do not need wireless access). We included a few exclusion regions in our design and found that LANPlanner does not try to avoid covering the area–rather it makes no attempt to ensure coverage there.


 


Quick Start uses these requirements to automatically place the optimal number of APs on the map, assigning channels and power settings to maximize signal-to-interference ratio (SIR). Quick Start also takes into account floor-to-floor interference, as well as co-channel interference generated by APs already on the map when invoked. A result summary indicates whether any clients lack sufficient coverage or capacity (for example, because doing so would require more APs than allowed by design parameters).


 


Go to page 3 of 3.

Visualizing predictions


After a WLAN design is created, LANPlanner uses predictive RF modeling to estimate how that network will perform. Those predictions may not be perfect; Motorola staff told us that designs created from AutoCAD files are often about 95 percent accurate when compared to post-deployment site survey data.


 


Nonetheless, reasonably-accurate predictions can save you a lot of time and money by letting you visualize coverage and set realistic expectations prior to deployment. For example, it’s trivial to view a high visibility area like a conference room, throwing in an extra AP to reinforce coverage and see what happens. During many installs, APs end up being mounted in slightly different locations than planned. A predictive modeler can let you “wiggle” APs on a map to anticipate the impact, stopping mistakes before they occur.


 


LANPlanner includes a suite of “Quick Predict” tools to simulate WLAN operation and visualize results. For example, Channel Planning predictions can plot simulated coverage for each assigned frequency. Contour predictions can display strong, moderate, or weak signal areas surrounding each device (AP or WIPS Sensor, see figure 2-5).


 


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Figure 2-5: Using Quick Predict to visualize sensor coverage. Click here for larger image.


 


Forward Link predictions let you drag your cursor around the map, simulating the received signal strength (RSSI) or throughput clients would experience in that location. Client parameters, such as transmit power and handoff threshold are globally configurable; setting them by throughput area might be handy for multi-media WLANs.


 


Pre-deployment refinements can be made to the design at this point. For example, Switches, WIPS Sensors, and external antennas can be manually added. Quick Start recommendations can even be adjusted–for example, LANPlanner assigned channel 34, but our Motorola AP-300s did not support that channel. (Ultimately, this proved irrelevant because we configured our APs for dynamic frequency selection instead of using static channel assignments.)


 


When design is complete, LANPlanner can generate a Bill of Materials (a list of equipment to be ordered, complete with model numbers and pricing) and a detailed site plan report that includes AP placement maps. However, we did not see any ability to generate AP installer “work orders” nor could we generate skeleton AP config files. On the other hand, we did export our design for use by RFMS, a sibling component of Motorola’s RF Management Suite (to be discussed in Part 4).


 


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Figure 2-6: Generating a Bill of Materials


 


Deploy and verify


After WLAN deployment, LANPlanner’s site survey feature can be used to verify performance. Survey results not only document actual WLAN performance; they can be used to fine-tune or expand the original design using “what-if” simulations.


 


LANPlanner site surveys can be conducted in two modes: RF Monitoring (where the client adapter gathers information about all APs by passively scanning the air) and AP Performance (where the client adapter associates to an individual AP to take specific measurements). Figure 2-7 illustrates measurement set-up and real-time display during an RF Monitoring run. To conduct this survey, we walked through the selected site floor, holding our LANPlanner laptop about three feet above the floor, pausing every few feet to mark our current location on the map (red dots).


 


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Figure 2-7: Conducting a site survey with LANPlanner


 


As shown in this figure, a surveyor can see visible APs and their properties in real-time. More importantly, all observations are written to an ASCII log file that LANPlanner uses to optimize its predictions and validate planned vs. actual WLAN performance.


 


Unfortunately, LANPlanner needs help to associate APs in the design with observed MAC addresses and SSIDs. Configuring those associations is a tedious task that would be onerous in a large WLAN. Associations were also problematic for virtual APs (MAC addresses with more than one SSID). We see definite room for improvement here.


 


Nonetheless, we found results worthwhile. After conducting a site survey, LANPlanner could easily generate channel, coverage, data rate, SSID, SNR, and noise heat maps for any region of the plan, using intuitive “check box” drill downs to focus on any individual element. For example, Figure 2-8 depicts a heatmap for a selected SSID and AP from a specific location, with forward link signal and noise experienced at the cursor location.


 


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Figure 2-8: Using survey results to map actual client coverage. Click here for larger image.


 


By combining a site’s RF model with in-situ measurements, LANPlanner can do a better job of predicting change impact. Some of the same tasks performed during initial design can now be repeated to see the effect of increasing the number of clients or adding new application regions. Quick Start can even be repeated on an existing WLAN to suggest where APs should be added or removed to meet revised requirements. However, LANPlanner won’t use survey results to automatically find trouble spots–it’s up to you to iterate the design process.


 


Conclusion


One of the first questions we asked about LANPlanner was 802.11n design support. Motorola recently announced the next generation of LANPlanner–version 11–will ship by the end of 3Q08. That update will reportedly be able to simulate performance of 802.11n APs like Motorola’s AP-7131. It will also provide a new wizard to assist with 11n migration and assess coexistence impact in mixed-mode WLANs.


 


Overall, our experience with LANPlanner version 10 was positive. In most cases, it made common WLAN planning and design tasks easy while providing hooks to accommodate more advanced needs. Learning how to interact with this GUI does take practice, but there’s no need to study a hefty manual or become an RF expert to benefit from LANPlanner. Wizards offer enough hand-holding to generate an initial WLAN design without much coaching from “Help.”


 


On the other hand, there’s much more to LANPlanner than our simple designs exercised. RF terminology can be intense, and the sheer number of parameters and views that LANPlanner can generate makes for lengthy menus. While novices can use LANPlanner, experienced engineers clearly get more benefit from it.


 


This product’s planning and design capabilities appear to be more streamlined and mature than its site survey and reporting tools. Nonetheless, anyone responsible for designing new 802.11n networks should consider investing in a predictive modeling tool like LANPlanner v11. After all, a LANPlanner license is no more than the installed cost of half a dozen APs–that’s a small price to pay to build a large WLAN right the first time.


 



Lisa Phifer owns Core Competence, a consulting firm focused on business use of emerging network and security technologies. With over 25 years of experience in the NetSec industry, she has been involved in wireless product and service design, implementation, and testing since 1997.


 

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