design

First Thing's First: Requirements.

*Originally published on Eddie's BadFi.com.

I was at a meeting today with a large Mechanical/Electrical Engineering firm who was in need of some wireless expertise. More, and more they are getting asked to include wireless "designs" for building projects and are finding (as many do) that it's not as simple as it seems.

The discussion took many turns, but often came back to something like, "So, if we have a school with say 35 students per classroom how many APs do we need?" My answer would be, "it depends." What does it depend on? Their requirements.

How many clients (not users, but devices)? What type of clients (1 stream, 2 stream, 3 stream)? What applications will they be using (e-mail & web, video streaming vs. YouTube caching, voice, etc) What are the bandwidth requirements for their State testing? And more.

The point was - just like they could not just "make up" an electrical, or engineering design out of the blue (How many people need to be in the space? What's the total power consumption required? Do we need HVAC in all locations?) - one could not just "make up" a WLAN "design" (Well, one could, but then you get what you get). That made total sense to them which was good.

I love explaining how wireless works and seeing their eyes light up. I love how it makes sense to them when I explain why they're not going to see 1.3GBs throughput, or adding more APs is not a default answer to a problem, how coverage & capacity are different things, how having a bunch of low-end single stream devices is not as efficient as have a bunch of 2, or 3 stream devices, etc.

The FIRST step to wireless network design, and the best way to avoid the BAD-FI, is to determine the REQUIREMENTS and EXPECTATIONS of the customer. Here just a few of things you should consider:

  • How many clients will be using the WLAN?

  • What are the types/capabilities of the devices? (# of streams, 5GHz support, DFS support, 802.11r/k/v support, etc.)

  • What applications will be using the WLAN and what are the requirements of those applications?

  • Is there a budget for the project?

  • Are there accurate, scale floor plans available?

  • What security and authentication types are you looking to support?

  • What the total bandwidth coming into your facility?

  • What is the time-frame for the project?

  • Aesthetics: Are external antennas ok? Do LEDs need to be off Should APs be inconspicuous?

  • Cable lengths: where are/is the MDF/IDFs located? More than 300ft from the APs?

These are a few off the top of my head, but you get the gist. DEFINE your requirements and expectations BEFORE you design a solution.

Anything else and you're just guessing.

Wireless LAN Troubleshooting & Design Guide

Aerohive Networks is offering this free WLAN Troubleshooting and Design Guide authored by CWNE #4 David Coleman and CWNE #7 David Westcott. This is actually chapter 12 of the Certified Wireless Network Administrator Guide (CWNA)

We would recommend buying the CWNA Study Guide to anyone who interested in, or has the responsibility of managing, WLAN. Put it on your shelf next to your copy of "Microsoft Exchange for Dummies" 😬. Read a chapter a day and you'll be amazed how much you'll learn and come to understand about how wireless works.

Either way, take advantage of this free download and the generosity of Aerohive Networks. Way to go guys! 👍

DOWNLOAD NOW!

Why Site Surveys Matter

There are those that think site surveys are a waste of time, and that Predictive Surveys alone (they are not surveys by-the-way) are enough to get the job done. Sometimes, if the building is new construction, or a very open floorpan, etc. you'll get lucky and things work out. But, as the Tweet above shows, just because a wall looks like it’s regular old drywall, doesn’t mean it is. Site surveys save a lot of heartache by taking as much guess-work as possible out of the equation.

I'm not saying that a full "AP-On-A-Stick" type survey needs to be done throughout the entire facility, but I am saying that you should collect as much data as possible. We do “Predictive Models” here at CommunicaONE for most of our designs. However, we take as much guessing out as we can by performing a site survey at the location we’re designing for.

Things you really want to know: attenuation/loss through walls, glass, tile (is this REALLY just drywall, or is or merely a facade over BRICK?) ; is there RF interference that may cause issues, are there fixtures, appliances, building materials that cause unexpected RF attenuation, reflections, refraction (oh, the 200 gallon fish tank wasn't in the floor plans?), scattering, etc. These are things that can only be known by a site survey. 

The moral here is when designing a WLAN you should get as much information as possible to about the environment you are designing for. Knowing what your building materials are, and what their RF characteristics are, will help go a long way in making WLAN designs as accurate, and successful as possible.

Not everyone has the time, nor can afford the tools needed to properly perform a survey. CommunicaONE can help by performing site surveys, spectrum analysis, and valuable data collection about your existing infrastructure, device types and capabilities, applications, and more, to help make sure that we have as much information as possible to design the best WLAN for your organization.

Hey, it’s a corporate blog, did you not expect a sales pitch? 😏

For a good overview of how to properly determine and document  wall attenuation see Devin Akin's blogpost here.

Very High Density 802.11ac Networks Validated Reference Design

Aruba has just released a VRD (Validated Reference Design) for Very High Density networks. This is a must read for anyone looking to deploy a WLAN for 10s of thousands of users.


Very high-density WLANs are defined as RF coverage zones with a large number of wireless clients and APs in a single physical space. For purposes of this reference design, a VHD WLAN is one that is designed to serve at least 100 devices per cell. A VHD WLAN may serve as many as 500 devices per cell. With the proliferation of wireless-enabled personal and enterprise mobile devices, a surprisingly diverse range of facilities need VHD WLAN connectivity:

  • Large meeting rooms

  • Lecture halls and auditoriums

  • Convention center meeting halls

  • Hotel ballrooms

  • Stadiums, arenas, and ballparks

  • Concert halls and amphitheaters

  • Casinos

  • Airport concourses

  • Passenger aircraft and cruise ships

  • Places of worship

The Ultimate Guide to modernizing classroom Wi-Fi [VIDEO]


Aruba recently hosted a webinar with industry expert Keith Parsons who explains how to create the perfect Wi-Fi network for one-to-one learning, how many Wi-Fi access points you need in a classroom, and how to choose the right Wi-Fi technologies to meet your needs.

Don't fall victim to the "One-AP-Per-Classroom" mantra. Watch Keith explain the proper way to plan modern classroom wi-fi.