Cisco Blogs


Cisco Blog > Mobility

HDX Blog Series #4: Optimized Roaming

Editor’s Note: This is the last of a four-part deep dive series into High Density Experience (HDX), Cisco’s latest solution suite designed for high density environments and next-generation wireless technologies. For more on Cisco HDX, visit www.cisco.com/go/80211ac.  Read part 1 here. Read part 2 here. Read part 3 here.

If you’ve been a long time user of Wi-Fi, at some point you have either observed someone encounter (or have personally suffered from) so called “sticky client syndrome”. In this circumstance, a client device tenaciously, doggedly, persistently, and stubbornly stays connected to an AP that it connected to earlier even though the client has physically moved closer to another AP.

Surprisingly, the reason for this is not entirely…errr…ummm…unreasonable. After all, if you are at home, you don’t want to be accidentally connecting to your neighbor’s AP just because the Wi-Fi device you’re using happens to be closer to your neighbor’s AP than to your own.

However, this behavior is completely unacceptable in an enterprise or public Wi-Fi environment where multiple APs are used in support of a wireless LAN and where portability, nomadicity, or mobility is the norm. In this case, the client should typically be regularly attempting to seek the best possible Wi-Fi connection.

Some may argue that regularly scanning for a better Wi-Fi connection unnecessarily consumes battery life for the client device and will interrupt ongoing connectivity. Therefore the “cure is worse than the disease”. But this is true only if the client is very aggressively scanning and actually creates the complete opposite of being “sticky”.

The fundamental issue with “stickiness” is that many client devices simply wait too long to initiate scanning and therefore seeking a better connection. These devices simply insist on maintaining an existing Wi-Fi connection even though that connection may be virtually unusable for anything but the most basic functionality. Read More »

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

HDX Blog Series #3: 802.11ac Beamforming At Its Best: ClientLink 3.0

Editor’s Note: This is the second of a four-part deep dive series into High Density Experience (HDX), Cisco’s latest solution suite designed for high density environments and next-generation wireless technologies. For more on Cisco HDX, visit www.cisco.com/go/80211ac.  Read part 1 here. Read part 2 here.

The 802.11ac wireless networking standard is the most recent introduction by the IEEE (now ratified), and is rapidly becoming more accepted and reliable industry standard. The good news is that the client and vendor adoption rate for 802.11ac is growing at a much higher pace as compared to when 802.11n was introduced back in 2009. There has been an accelerated growth seen with the mobile and laptop devices entering the wireless market embedded with an 802.11ac WiFi chipset. Unlike in the past, laptop, smartphone and tablet manufacturers are now acknowledging the fact that staying up to date with the latest Wi-Fi standards is as important for the bandwidth hungry users as having a better camera or a higher resolution display.

With the launch of the new 802.11ac AP 3700, Cisco introduces the Cisco HDX (High Density Experience) Technology. Cisco HDX is a suite of solutions aimed towards augmenting the higher performance, more speed and better client connectivity that 802.11ac standard delivers today.

ClientLink 3.0 features as an integral part of Cisco HDX technology designed to resolve the complexities that comes along with the new BYOD trend driving the high proliferation of 802.11ac capable devices.

So what is ClientLink 3.0 technology and how does it work?

ClientLink 3.0 is a Cisco patented 802.11ac/n/a/g beamforming technology Read More »

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

HDX Blog Series #2: Scaling with Turbo Performance

Editor’s Note: This is the second of a four-part deep dive series into High Density Experience (HDX), Cisco’s latest solution suite designed for high density environments and next-generation wireless technologies. For more on Cisco HDX, visit www.cisco.com/go/80211ac.  Read part 1 here

With any new technology comes a new set of obstacles to overcome.  802.11ac is no exception.  Last week we talked about CleanAir for 802.11ac and why spectrum intelligence still matters. Another challenge is scalability. In this post I will give you some details on new HDX feature, Turbo Performance, which allows the AP 3700 overcome common scaling issues to scale amazingly well.

What’s Different with 802.11ac?

802.11ac means higher data rates, which means more packets per second (PPS).  There are three reasons for more PPS with 11ac: wider channels, increased modulation and increased aggregation.  Channel width doubled to 80 MHz, modulation increased from 64 QAM to 256 QAM, and aggregation increased from 64k to 1MB!

With 802.11n, an AP might have had to push 30,000 1500 byte packets per second through the APs data plane. Today with 802.11ac that could now be 75,000+ PPS.  More PPS means more load on the APs CPU, so to really keep up with the demands of 802.11ac, we needed to go back to the drawing board.   Read More »

Tags: , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

HDX Blog Series #1: Why Spectrum Intelligence Still Matters

Editor’s Note: This is the first of a four-part deep dive series into High Density Experience (HDX), Cisco’s latest solution suite designed for high density environments and next-generation wireless technologies. For more on Cisco HDX, visit www.cisco.com/go/80211ac

CleanAir for 802.11ac:  Why Spectrum Intelligence Still Matters

In wireless networking and communications, as with life, nothing good comes for free. It’s well known that the primary feature of the new IEEE 802.11ac amendment is support for an 80 MHz-wide channel. The benefit of an 80 MHz channel is the potential to double usable throughput in comparison to that of 802.11n using a 40 MHz wide channel.

However, what is less well known is that a wider RF channel is also more susceptible to interference. In other words, 802.11ac devices “hear more” than 802.11n devices, primarily due to the wider channel support. It should be noted that this is not a flaw in the 802.11ac amendment, it’s simply basic communications theory.

Nevertheless, there is far more to building an 802.11ac access point than simply meeting the standard. Not all 802.11ac access points perform equally without interference. But more importantly, not all 802.11ac access points perform well in the presence of interference.

Furthermore, there is far more to deploying High Density wireless LANs than only considering the performance of individual access points. Read More »

Tags: , , , , , , , , , , , , , , , , , , ,

Prepare Your Networks for High Density without Compromising on Performance

A new year means new users and new devices. More devices means more network crowding. Mobile users demand bandwidth and speed, while the network is increasingly overwhelmed by the sheer number of devices. The networks of today and tomorrow have to be ready for high client density environments.

That’s why we’ve developed the Cisco High Density Experience (HDX). I announced HDX in a blog last October with a high level look at Cisco’s answer to handling high client density environments. Each feature in the HDX solution was designed specifically to alleviate the introduction of more clients, more bandwidth hungry applications to provide an unparalleled user experience.

Starting tomorrow we’ll kick off an HDX blog series to dive deep into the four key features that come with HDX:

  1. January 8: CleanAir
  2. January 13: Turbo Performance
  3. January 27: ClientLink 3.0
  4. February 10: Optimized Roaming

For more on Cisco’s approach to 802.11ac, visit www.cisco.com/go/80211ac.

 

Tags: , , , , , , , , , , , , , , , , ,