Certified Wireless Network Professional (CWNP) Wireless LAN training courses and Certification

The Complexities of Wi-Fi

Wi-Fi is far from simple. If a potential supplier tells you that it is, you should look for another supplier.

LEVER's Wi-Fi Network Professional (WNP) training programme spans 20 unique days of training.

The majority of people - IT professionals and users alike - completely under-estimate the complexities of Wi-Fi networking.

As independent consultants, we can see that today's network engineers lack the essential skills needed to Plan, Design, Survey, Implement, Secure and Support enterprise-grade Wi-Fi networks.

Many wireless network installation companies are lacking in the vital Wi-Fi network Planning, Design and Survey skills too.

The consequences - which we see every week - are that many Wi-Fi networks being installed today are poorly designed and engineered.

Many are simply unfit for purpose.

Bad Practice in the Wi-Fi Industry

During LEVER's six years experience in the wireless network industry, we have been contracted by companies of all kinds, including end-user companies operating in most market sectors.

We have seen countless examples of poor practice in terms of wireless network planning, design, survey, installation, configuration, support and troubleshooting.

It is unfortunately our firm opinion that the vast majority of companies that conduct wireless network site surveys and who install wireless networks, have totally inadequate knowledge, skills, tools and experience to perform these tasks competently.

Just some of the most common mistakes that we have encountered are listed below. We hope that this will help anyone who is contemplating sourcing a wireless network - to help select the appropriate supplier for their needs.

Problem   Comment
Not understanding the customer's requirements properly, or at all.

  LEVER conduct a structured user needs analysis session during Phase 1 of our Wi-Fi projects. We employ a detailed Pre-Survey Questionnaire, which we help our customers to complete.

Not defining the customer's requirements.

  LEVER perform Application Chacterisation, before defining the wireless network requirements.

Not stating the design parameters for a customer's wireless network.   LEVER define the Wi-Fi RF network requirements in terms of coverage, capacity, cell overlap, signal strength and SNR.

Not designing the wireless network to meet any stated or relevant design parameters.

  Before surveying the customer's premises, LEVER perform Wi-Fi network design and modelling using advanced WLAN simulation tools.
Not designing the wireless network to deliver RF coverage to the areas required.

  Over the past six years, LEVER have developed a range of specialist Wi-Fi network designs and solutions to meet the needs of specific marrkets and environments.

Employing the wrong antenna types in a wireless network.

 

There is now excuse for this, but too many companies use Omnidirectional antennas where they shouldn't. Panel, Yagi and other types of WLAN antennas are designed for specific purposes.

  Even where an omni antenna is the right choice, we often see these located in the wrong places.

Stating that the WLAN antennas should have a gain of "at least 2.2dBi", in an environment and where greater gain would degrade the network through mutual interference, and where the EIRP levels would be illegal.

  LEVER design and survey RF networks precisely. You'll find no mention of "at least" in our documents.

Trying to employ Omnidirectional antennas as Yagi antennas.

  Even the core Technical Assistance Centres of the biggest names in Wi-Fi get this wrong. Why? They lack the essential training and skills.

Having too many wireless access points located in close proximity.

  You may have read that having more wireless access points increases capacity - it often has the reverse effect.

Not appreciating the adverse effects of mutual interference between wireless access points and wireless client devices.

  Mutual interference is the capacity-killer, and we have seen this render a 240x AP network unusable. Proper Wi-Fi design and survey techniques are needed to eliminate

Assigning overlapping RF channel numbers to wireless access points that are in proximity to each other.

  Even the biggest name in Wi-Fi site survey tools got this wrong!

Installing wireless antennas in poor locations.

 

Installing wireless antennas in poor locations.

  Proper coverage is the primary requirement of a wireless access point or antenna, but this requires proper a proper understanding and visualisation of the RF radiating from an antenna.

Installing wireless antennas in close proximity to RF barriers and reflecting surfaces.

  LEVER employ specialist mounting hardware to ensure that the "obviousl" problems are avoided.

Giving the impression in a site survey report that heatmaps were generated after detailed on-site survey, when in truth they were generated by:
  • Software simulation, and even
  • Graphical drawing tools

  There's no excuse for this: either a Desktop survey or On-Site RF survey is being performed. The two can then be combined, but openness and clarity are needed where modelling or simulation are being empoyed.

Presenting heat maps with no scale of units, and even with no stated scale at all (e.g signal strength, associated data rate, SNR, etc).

  This is a sure sign that the "designer" doesn't now what they're doing and/or they're trying to pull the wool over your eyes!

Surveying a wireless network using completely inappropriate tools, such as the Cisco Aironet Site Survey Utility.

  Guess who used this utility to survey a UK NHS Trust on a 14-day site survey assignment?

This was a totally inadequate and inappropriate site survey; and not only for the reasons stated here.

LEVER employ only state-of-the-art tools for Wi-Fi network site survey.

Placing access points in the wrong orientation, including orienting them vertically when they should be oriented horizontally.

 

Not assigning fixed RF channels to APs, but instead using a "Least Congested Frequency" setting.

  This is a nother clear sign that a network is not properly designed, and is improperly configured.

Setting RF power levels too high: from a mutual interference perspective.

  If a company doesn't understand mutual interference and how to design a network to avoid it, don't use that company!

Setting RF power levels too high, from a UK / EU legislative perspective: the wireless network was operating illegally.

  This puts you in breach of the Law, and is completely unnecessary. It highlights poor or non-existent design, and should be avoided at all costs.

Setting 5GHz RF channels manually (disabling DFS): the wireless network was operating illegally.

  We know that some Wi-Fi network suppliers do this deliberately!

It's best to ask them beforehand about DFS and it's drawbacks. Then call LEVER.

Disabling Transmit Power Control (TPC): the wireless network was operating illegally.

  Again, we know that some Wi-Fi network suppliers do this deliberately!

It's best to ask them beforehand about TPC and it's use. Then call LEVER.

Expecting a Wireless LAN Controller's "AutoRF"-type RF power and channel management to deliver a satisfactory wireless network configuration.

  The fact is that most times, the automatic RF capabilities of Wireless LAN Controllers and Switches has insufficient knowledge of the RF environment to do the job.

Proper Wi-Fi network design and survey should assign specific channels and power level settings to 802.11bgn (2.4GHz) radios.

Supplying and installing inappropriate wireless network hardware.

  SOHO-grade Wi-Fi access points cannot deliver the wireless network coverage, capacity, services and managegeability that business, colleges and schools require.

If you're offered hardware of this kind, find another supplier.

Misleading the customer to believe that problems experienced with their wireless network were due to external interference, when in fact the cause was poor RF network design.

  We find that "interference" is all too often blamed as the cause of problems with wireless networks, yet this is rarely the case. Usually, it is due to either:
  • Poor network design, or
  • Poor network configuration
However, LEVER can assess interference problems using a range of mathods, which include RF Spectrum Analysis - a field in which we have more than 20 years experience.

Claiming that a Wireless LAN Controller was required, to resolve network problems.

  WLAN controllers rarely solve problems: it's the services of a Wi-Fi Expert that are usually required.

Claiming (counter to their own design documents) that antenna spacing was the problematic cause.

  There are rules for spacing between diversity antenna, but there is disagreement on the part of some manufaturers as to what this should be.

As with many misleading articles and white papers, this is usually due to someone attempting to over simplyfy what is really a more complex issue.

Stating that DECT phones and other devices interfere with Wi-Fi network operations, when they do not.

  DECT phones operate in the 1880MHz to 1900MHz spectrum range (although other bands have also been allocated). Wi-Fi devices use totally different spectra.

If a supplier's proposal or survey document suggests otherwise, give LEVER a call.

Claiming that spectrum analysis had been performed when it had not. There was no data presented and nothing to substantiate the claim that external interference was the cause of the customer's problems.

  If your supplier does not present screenshots or recordings of spectrum analysis at your premises, this should be a cause for concern. Ask to see the data.

Claiming that their consultant was independent: the consultant in fact worked for the company that had installed the non-functional network.

  LEVER are truly independent, and we're vendor-neutral too, since we regularly work with most vendor's hardware and resell products from mutiple vendors.

 

Some of the gravest errors have been made by some of the very biggest names in the Wi-Fi industry.

How can you prevent this happening within your organisation?

Just 895 Could save you Tens of Thousands ...

... from as little as 895, your staff can be trained in professional Wi-Fi network planning and design.

A more comprehensive Wi-Fi Network Professional training programme will enable your organisation to:

  • Ensure that your Wi-Fi network requirements are properly understood and defined.
  • Plan and Design your Wi-Fi network deployments professionally.
  • Evaluate the Wi-Fi products that they are offering.
  • Evaluate potential suppliers rigorously.
  • Evaluate and critique Wi-Fi network proposals from potential suppliers.
  • Significantly reduce the cost of your Wi-Fi network deployments.
  • Move forward confidently with your corporate Wi-Fi strategy.

Contact LEVER now and learn more about the unique benefits of Wi-Fi training with LEVER.

Call free on 0800 138 3030 (UK) or +44 113 398 3300 (International), or e-mail
                     

© 2016 LEVER Technology Group PLC