Home > 802.11ac, 802.11n, Best practices, WiFi Access, WLAN networks, WLAN planning > 11 Commandments of Wi-Fi Decision Making

11 Commandments of Wi-Fi Decision Making

September 4th, 2013

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Are you considering new Wi-Fi deployment or upgrade of legacy system? Then you should be prepared to navigate the maze of multiple decision factors given that Wi-Fi bake-offs increasingly require multi-faceted evaluation.

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Follow these 11 “C”ommandments to navigate the Wi-Fi decision tree:

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  1. Cost

  2. Wi-Fi CommandmentsComplexity

  3. Coverage

  4. Capacity

  5. Capabilities

  6. Channels

  7. Clients

  8. Cloud

  9. Controller

  10. 11aC, and last but not least …

  11. seCurity!

 

|hemant C tweet

 

1) Cost:

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Cost consideration entails both “price and pricing” nuances. Price is the size of the dent to the budget and everyone likes it to be as small as possible. Pricing is the manner in which that dent is made – painful or less painful (I don’t think it can ever be painless!). One aspect of pricing is the CAPEX/OPEX angle. Other aspects such as licensing, front loaded versus back loaded, maintenance fees etc. have been around for a long time, so I won’t drill into details of those other than to say that they exist and need to be considered. Enough said on cost.

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2) Complexity:

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Complexity consideration spans deployment, configuration and ongoing maintenance. One pitfall to avoid is to “like complexity in the lab and then repent it in the production”. Too many knobs to turn and tune, excessive configuration flexibility and exotic features are some of the things that can add to complexity. That said, complexity considerations cannot swing to the point of being simplistic. Rather, the balanced approach is to look for solutions that have mastered complexity to extract simplicity to meet your needs (borrowing from Don Norman’s terminology here).

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3) Coverage:

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When you hear terms like neg 55, neg 60, neg 65, you know people are reconciling coverage expectations to the number of access points. There’s no explanation needed for how important the coverage is for your wireless network, but the important factor is that the coverage determines the number of access points needed to cover the physical area. At the planning stage, RF predictive planning comes in handy to estimate the coverage BOM (a site survey can complement it for sample areas during the evaluation stage).

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4) Capacity:

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While coverage determines how far, capacity determines how many or how much. Capacity determines how small or large cells can be. Using practical models for Wi-Fi usage, capacity objectives can be set and network design can be evaluated against these factors. Capacity also determines the number of access points needed to provide the desired capacity in the physical area. RF predictive planning tools can be invaluable during the evaluation phase for capacity estimation.

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5) Capabilities:

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By capabilities, I mean feature set. This is one of the most important aspects because this is where you ask the question: “Will the Wi-Fi serve the needs of the business?” This is very industry specific. Some features are extremely critical for one vertical, but won’t even be noticed in others. So, it’s important to identify both the features you care about and also those for which you don’t.  Once identified, you move on to thoroughly evaluate the ones you care about.

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6) Channels:

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One aspect of channels is making decision on how the RF network will be provisioned along the lines of 2.4 GHz and 5 GHz operation. There are advantages to 5 GHz operation, but 2.4 GHz is not EOL yet. How applications are split between the two bands determines the number and type of radios required in the design. Tools and techniques that are needed to plan, monitor and adapt to the dynamic RF environment are also an important consideration.

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7) Clients:

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Much of what is achievable in Wi-Fi network depends upon the capabilities of the client devices that will access the wireless network. One set of considerations is mainly around the radio capabilities of clients such as 2.4 GHz/5 GHz operation, number of radio streams, implementation of newer standards in clients etc. Another set of considerations revolves around the applications they run and the traffic profile these applications generate. Yet another set of considerations centers around the level of mobility of the clients. BYOD is another consideration that has become important in the the clients arena.

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8) Cloud or 9) Controller:

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Today, we see pure cloud architecture, pure controller architecture and also architectures confused between the two concepts. While vendors and experts spar over which is the right architecture for today’s and tomorrow’s Wi-Fi, evaluators should focus on comparing them based on their derived value. It is also important to understand what cloud and controller concepts actually mean from the data, control and management plane perspective. Cloud and controller are distinct ways of organizing overall Wi-Fi solution functionality.

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10) 11aC:

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Making judicious decisions on “what to deploy today or whether to upgrade now” is a tricky one. There are many views around it. One reason is because of how the features of 802.11ac are split between Wave-1 and Wave-2. It is also important to note that immediate 802.11ac benefits are application and vertical specific. Several practical network engineering considerations exist beyond the casual description of the new 802.11ac speeds that are often marketed. So, listen to vendors, listen to business needs, listen to experts, analyze yourself, and in the end, do what is the best for your environment and situation. Speed is nice IF it can be leveraged in practice!

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11) SeCurity:

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Any information system sans security is worse than worthless – especially today. That said, level of security required by the wireless environment depends on factors such as the value of information at risk, compliance requirements and enterprise security policies. Desired security level determines the right mix of data inline security (encryption, authentication) and security from unmanaged devices (WIPS). Talking of WIPS, the biggest red flags to watch for are trigger happy solutions that generate false alarms, boast long list of ”popcorn” alerts and require excessive manual involvement in the security process.

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My hope is that these “C”ommandments will help serve as guidelines in your Wi-Fi decision making process. You can follow them in any order you like to ensure holistic evaluation of options before you. Every vendor, big or small, has sweet spots on some dimensions and not so sweet spots on others. So, despite what they tell you, nobody scores all A’s on all C’s. Hence one has to work on the evaluation criteria until the palatable scorecard is achieved consistent with requirements and budget.

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Additional References:

 

Hemant Chaskar

Hemant Chaskar is Vice President for Technology and Innovation at AirTight. He oversees R&D and product strategy for AirTight Wi-Fi and WIPS; and also performs roles in technical marketing, business development, and customer facing activities. Hemant has worked for more than 14 years in the networking, wireless and security industry, with 9 years in Wi-Fi. He holds several patents in these technology areas and has Ph.D. in Electrical Engineering from the University of Illinois at Urbana-Champaign. Follow on Twitter @CHemantC.

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Comments

  1. October 23rd, 2013 at 05:52 | #1

    Nice post Hemant, A very important point regarding security which I feel like sharing is that the ultimate in wireless security measures is shutting down your network. It will most certainly prevent outside hackers from breaking in! While impractical to turn off and on the devices frequently, at least consider doing so during travel or extended periods offline. Computer disk drives have been known to suffer from power cycle wear-and-tear, but this is a secondary concern for broadband modems and routers.

  2. September 10th, 2013 at 03:14 | #2

    Keith,

    Both good points. CCI is very important and I took it implicitly under channels/capacity/coverage aspects. However, given its importance, it can also be listed as a separate issue. And good thing is that it also is a “C”, so it can then be 12 “C”ommandments.

    Also, I think it is perfectly alright to move these things up and down the list. I did not intend to imply any order and actually said so in wrapping up. They are more like sectors on a wheel.

    Cheers,
    Hemant

  3. September 5th, 2013 at 07:19 | #3

    I think you missed one of the ones that is hardest to design out of your Wireless LAN – and it fits in your alliteration…

    “Co-Channel Interference” – the bane of all WLAN Designers – the thing that causes more harm to Wi-Fi and steals throughput.

    I’d also like to move ‘cost’ to the bottom of the list – when you design for cost, you design for failure in meeting all the other design requirements…

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