Archive for the ‘WLAN planning’ Category

Channel Bonding Caveats – Over and Above Spectrum Hogging

July 14th, 2014

Popular literature on 802.11ac describes 40 MHz and 80 MHz operation (channel bonding) as doubling and quadrupling of the data rate, respectively. Every time I saw that mentioned, the following question came to my mind.

When radio transmits over 40 MHz (or 80 MHz) channel, is the total transmit power proportionally increased over 20 MHz to maintain the SNR (signal to noise ratio)? And, how is the data rate multiple with channel boding distributed over the cell?

This question nagged me like a little stone in the shoe that is impossible to ignore. My subsequent findings from the lab tests show that the popular literature is only partially true. Read on to find out why. Read more…

802.11ac, WLAN planning , ,

Management System Diversity: “Manage WLANs from Anywhere Using Anything!”

April 2nd, 2014

So much competitive marketing noise has been made over the last half dozen years about managing WLANs that vendors are now trying to manage WLANs from anywhere using everything. It wouldn’t surprise me in the least to hear a vendor say that they can now manage a branch WLAN in France from the comfort of their kitchen’s refrigerator’s management widget. It has gotten downright silly. I thought I would recap just how diverse the WLAN management scene has become: first for a good laugh, and second as a reference for those newcomers to the Wi-Fi industry.

You may be thinking, “why are there so many ways to manage a Wi-Fi system?” There’s a variety of answers to that question, such as:

  • Cost
  • Differing use cases
  • Partner eco-system
  • User preference

Not every vendor provides each of the management methods described below, but rest assured that every vendor will tell you that you don’t need anything other than what they sell. Can I get an amen? Below, I have offered a visual reference of the seven prevalent methods of managing a Wi-Fi infrastructure. It’s important to note that I will not address Wi-Fi client management methodologies in this post.


Read more…

WLAN planning

Away from Corner Cases: High Density, Low Throughput Wi-Fi

March 19th, 2014

In my blog called Corner Cases, I mentioned that high density, high throughput (HDHT) cases are in the extreme minority (<1%). In this blog, I would like to discuss High Density, Low Throughput (HDLT), which I believe will be the situation that over half of the installed Wi-Fi infrastructures of the world will face at some point over the next 5-7 years. I want to clarify that that when I use the term “high density”, I’m referring to client density (lots of clients in a physical area), not AP density (lots of APs in a physical area).

Unless you’ve been camping out under a rock, you may have heard the term “Internet of Things” or IoT for short. This moniker refers to the movement toward connecting previously-unconnected devices onto the Internet. To clarify, things are being connected to the Internet, thus we get Internet of Things. So how many of these things are we talking about? Oh… a few I suppose. Gartner is saying there will be 26 billion IoT devices and an additional 7.3 billion smartphones/tablets/PCs by 2020.

Read more…

WLAN planning

Corner Cases

February 26th, 2014

Most Wi-Fi manufacturer’s marketing departments would have you believe that 99% of all deployments are what I’d call “corner cases.” I call B.S. (as usual).

Here are the high-density/high-throughput (HDHT) corner cases that so many manufacturers would have you believe are so prevalent:

  • Large K-12 and University libraries, cafeterias, lecture halls, and auditoriums
  • Stadium or gymnasium bowls
  • Large entertainment venues (e.g. music and theater halls, night clubs)
  • Trade shows
  • Urban hotspots
  • Airports

Read more…

WLAN planning

11 Commandments of Wi-Fi Decision Making

September 4th, 2013


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.


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


  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


Read more…

802.11ac, Best practices, WLAN planning , , , , ,

802.11ac (Wave-1): MORE Network Engineering Insights

June 24th, 2013

802.11ac more engineering insightsIn my previous blog on the 11ac series, I explored 80 MHz channel operation in 802.11ac in the context of data rate, OBSS (Overlapping BSS), network throughput, and auto-channel assignment.

802.11ac (Wave-1): Network Engineering Insights

In the present post, I explore the other speed factor of 1.33X that shows up in the Wave-1 data rate equation: (2.16 x 1 x 1.33) x 450 Mbps of 802.11n rate = 1.3 Gbps. This 1.33X factor is attributed to the new modulation technique called 256-QAM introduced in 802.11ac (802.11n had only upto 64-QAM). Consistent with the theme of this blog series that the data rate equation does not bring out critical network engineering aspects, this post explores 256-QAM from the enterprise network design perspective.

Read more…

802.11ac, WLAN planning

How to implement BYOD with Wi-Fi / WIPS assist

June 18th, 2013

BYOD Bring Your Own Device


Wi-Fi has become the de facto access medium for smart mobile devices in enterprise networks. Sitting at the edge of the network, Wi-Fi can assist greatly in implementing secure and disciplined BYOD in these networks.

There is no one-size-fits-all when it comes to BYOD management in the enterprise. However, from my experiences working with Wi-Fi and WIPS deployments, I have seen certain features that are particularly useful for organizations in implementing BYOD. This blog post explores some of these in greater detail. |


1)      Monitor new devices entering Wi-Fi


Monitoring for new smart devices entering the network is a first and important step in the implementation of disciplined BYOD. Wireless clients connecting to Wi-Fi are fingerprinted using packet level and protocol level characteristics to identify smart mobile devices.


WPA2 alone is not sufficient to stop personal devices from entering the protected Wi-Fi network.

|Monitor new devices entering Wi-Fi


2) Enforce pre-configured policies on new devices entering Wi-Fi


Once a new smart mobile device is detected in the Wi-Fi network, different types of pre-configured policies can be automatically implemented. For example, one policy would be to block or limit access to new smart devices pending authorization. The Wi-Fi/WIPS solution can facilitate such policy enforcement by blocking new devices from accessing the secure network or provide them only limited access (e.g., access to only Guest SSID) until they are approved by IT administrator. |

Devices pending review |

3)      Automated approval/onboarding of new devices on secure Wi-Fi


Using mobile apps provided by Wi-Fi/WIPS vendor:  With the rising volume of new devices entering the network, manual approval and inventory may prove to be cumbersome. Using onboarding apps provided by the Wi-Fi/WIPS vendor, this process can be automated. New smart mobile devices are redirected to a portal and upon installation of the onboarding app, devices are allowed to enter the protected Wi-Fi. The onboarding app facilitates automated inventory and tracking for smart devices after they are admitted into the secure network. This app can also automatically configure secure WPA2 settings on the device without administrator intervention.

| Onboarding with AirTight Mobile app


Using third party MDM agents: Many organizations deploy specialized MDM (Mobile Device Management) systems to manage smart mobile devices accessing corporate assets. Several MDM systems choices are available in the market. So, BYOD onboarding workflow in a Wi-Fi solution that facilitates device onboarding with third party MDM agents is useful. With this workflow, new devices attempting to connect the network without hosting the MDM agent prescribed by IT are detected and redirected to install the MDM agent. Upon installing the MDM agent, they are allowed to enter the protected Wi-Fi. A point to note here is that MDM alone does not complete the BYOD story, combination of MDM and Wi-Fi gatekeeping is what is required. This is because MDM can control only managed devices, but Wi-Fi/WIPS gatekeeping detects unmanaged devices and helps bring them under MDM control. Airtight Wi-Fi provides API to implement this workflow using third party MDM agents.


4)      Wireless security for the admitted devices


Once admitted into the network, the mobile devices need to be afforded strong protection from vulnerable wireless connections and wireless attacks including rogue APs, tethering, personal hotspots, Wi-Phishing, client connections to neighborhood APs, ad hoc connections, etc.  With BYOD, the sheer volume of wireless endpoints seen in the wireless environment is expected to triple or quadruple over next 2-3 years. As a result, fully automated strong WIPS, free from false alarms and not requiring excessive configuration and signature maintenance is needed to be the part of the Wi-Fi solution in order to implement truly secure BYOD. |

As we can see, enterprises can take advantage of many Wi-Fi and WIPS features to implement secure and disciplined BYOD in their networks. These features range from identifying new smart devices entering the network to assist in smooth onboarding of the new devices to securing the new devices once they are admitted into the secure Wi-Fi networks. So don’t get stressed by BYOD, there are Wi-Fi and WIPS to assist you.


Additional Information:


BYOD, WLAN planning

802.11ac (Wave-1): Network Engineering Insights

June 6th, 2013

Have you noticed all the buzz on 802.11ac especially now that Wave-1 has arrived?

How could you not!  802.11ac is the new Wi-Fi standard and it has new techniques to increase the wireless data rate above the existing 802.11n standard.

11ac is slated to arrive in two Waves – Wave-1 this year and Wave-2 next year.

At its full potential (Wave-2), the standard is characterized as: 802.11ac max data rate of (4.33 x 2 x 1.33) times the 600 Mbps max data rate of 802.11n, which comes out to be about 6.9 Gbps. The current version (Wave-1), which is commercially limited to 80 MHz channels and 3 spatial streams per AP, the standard is characterized as: 802.11ac max data rate of (2.16 x 1 x 1.33) times the 450 Mbps current data rate of 802.11n, which comes out to be about 1.3 Gbps. It is also important to note that Wave-1 does not have MU-MIMO. The MU-MIMO effect does not explicitly show up in the data rate equations, but it can have profound benefits in practice. |

So what is missing in the above characterization?

| N802.11ac (Wave-1): Network Engineering Insights etwork engineering insights – that’s what is missing!  There are several network engineering nuances which do not show up in the above equations. I will discuss them in a series of blog posts starting with this one. In this initial post, the focus is on the nuances of operating 80 MHz channels in the practical network deployments. These 80 MHz wide channels are responsible for the first multiplicative factor of about 2X in the Wave-1 data rate equation.

Read more…

802.11ac, WLAN planning , , ,

Don’t deploy 802.11ac without thorough RF planning

May 29th, 2013

Wi-Fi RF Planning has never been trivial


AirTight Planner : the solution to all your RF planning questionsTraditionally, anyone contemplating Wi-Fi deployment has always faced questions like:

  • How many access points?
  • Where do I install them?
  • What channels should they operate on?
  • Will the deployment meet my coverage and capacity objectives?
  • What will be my security exposure?  and so on.

Due to the myriad of issues that need to be addressed while making these determinations, manual processes and rules of thumb have always been cumbersome and/or imprecise, particularly for Wi-Fi deployments with large footprints.


802.11ac will only exacerbate RF planning challenges


802.11ac adds more elaborate channeling structure and new techniques to raise wireless data rates. 802.11ac is slated to arrive in two Waves – Wave-1 this year and Wave-2 next year. While the decibel level in the market is raised to prematurely hasten the 802.11ac upgrade cycle, the reality is that this is just the beginning of Wave-1. Many people may not see justification to jump on Wave-1 due to a myriad of practical, network engineering, and interoperability issues that Wave-1 faces. Also important is the fact that Wave-1 lacks the complete feature set of  802.11ac and new radios will be required when Wave-2 hits with those features. All this points to Wave-2 next year to be realistic timeline for large scale network upgrade to 802.11ac.

Read more…

802.11ac, WLAN planning

The WiSE Article Series on CWNP

May 8th, 2013


CWNP (Certified Wireless Networking Professional) is widely recognized as the IT industry standard for vendor neutral enterprise Wi-Fi certification and training.  CWNP publishes videos, white papers, blogs, and other materials that assist the networker in learning Wi-Fi technologies and preparing for CWNP certification exams. The WiSE article series is one of these CWNP thought leadership content initiatives.


About the WiSE Article Series:


CWNP (Certified Wireless Networking Professional)Wireless is inherently complex; its study spans at least two engineering disciplines: Electrical Engineering and Computer Science. Add to this the nuances of various standards, vendor implementations, RF environments, and protocol interactions, and it is not uncommon to feel a little lost in understanding the various aspects of Wi-Fi network operation. In this series of short articles, we explain various Wi-Fi subtleties, to work toward a better understanding of Wi-Fi network deployments.

The WiSE article series editor is Tom Carpenter and the first 5 WiSE articles feature AirTight Networks wireless subject matter experts as CWNP guest bloggers.


1) Wi-Fi Throughput Algebra – Simplified

Author: Bhaskaran Raman, PhD.     Read WiSE article 1

In this first article in a multi-part WiSE Article Series, Bhaskaran Raman explains the formulas you can use to estimate throughput on WLANs. This article simplifies Wi-Fi throughput algebra, to give a rule of thumb for what throughput to expect when taking into account at least the first order factors which affect all environments and tests.   Read WiSE article 1


2) Wi-Fi Subtleties Explained (Parameters that Matter)

Author: Bhaskaran Raman, Ph.D.     Read WiSE article 2

This second article talks about parameters that impact Wi-Fi throughput. You may be surprised to learn that it’s not all about the lower layers (Physical and Data Link), but the TCP communications have a significant impact as well.   Read WiSE article 2


3)  Wi-Fi Subtleties Explained (Channel Bonding)

Author: Bhaskaran Raman, Ph.D.     Read WiSE article 3

In this third installment of the WiSE article series from AirTight Networks, channel bonding is considered. Some surprising results will cause you to rethink your network design plans and possibly how you will implement newer 802.11 technologies.  Read WiSE article 3


4)  Wi-Fi Subtleties Explained (Quality of Service [QoS] Controls)

Author: Hemant Chaskar, Ph.D.     Read WiSE article 4

Quality of Service (QoS) is another aspect of the network performance that is relevant for applications such as VoIP over Wi-Fi. In this context, QoS is provided by prioritizing the packets belonging to specific applications such as VoIP over others so that they encounter minimal latency in transit. It takes three different sections of the data path to use three different techniques for the end-to-end handling of wireless QoS-sensitive packets, as discussed below. The idea of this article is not to provide overview of standard Wi-Fi QoS mechanisms such as WMM, but to point out some subtleties in using them in the network.   Read WiSE article 4


5)  Interference from Non-WiFi Sources, Part 1

Author: Bhaskaran Raman, Ph.D.     Read WiSE article 5 – part I

RF interference is an important concern in Wi-Fi networks. Such interference can come from two types of sources: Wi-Fi or non-Wi-Fi. In this and the follow up article, the focus is on subtleties pertaining to non-Wi-Fi interference sources.  Read WiSE article 5 – part I


Full list of CWNP WiSE articles

Check back often as new articles are published on a regular basis.


About the AirTight WiSE authors:


Bhaskaran Raman is a scientist at AirTight Networks, working on high performance Wi-Fi architecture. Bhaskar received his M.S. and Ph.D. in Computer Science from the University of California, Berkeley, in 1999 and 2002 respectively, and his B.Tech in CSE from IIT Madras, India in May 1997. He was a faculty in the CSE department at IIT Kanpur from 2003-07. Since July 2007, he has been a professor at the CSE department at IIT Bombay. His research interests and expertise are in wireless and mobile communication networks. Bhaskar was a recipient of the IBM Faculty Award in the year 2008. He has published research papers in various IEEE and ACM conferences and journals, and is on the editorial board of ACM Computer Communication Review.

Hemant Chaskar is VP for Technology and Innovation at AirTight Networks. In this role, he looks after AirTight’s technology R&D and also performs roles in product design, business development, and various customer facing activities. At AirTight, Hemant has been working on Wi-Fi networking and security for the past 8 years; and has held positions at Nokia Research and Lucent Technologies prior to that. He holds Ph.D. in Electrical Engineering from the University of Illinois at Urbana-Champaign.


Additional Information


Follow CWNP on Twitter

Contact Tom Carpenter – WiSE Article Series Editor

More information on CWNP certifications

Follow Airtight on Twitter

Contact Bhaskaran Raman and Hemant Chaskar at AirTight Networks


WLAN planning , ,