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Category Archives: 802.11n

WildPackets in the NOC

The world’s largest independent IT conference, Interop, could not run without its network, InteropNet. And, InteropNet could not run without a group of volunteers and vendors that are selected each year to collaborate and run the expo’s network from the Network Operations Center (NOC).

This week, you will not only find us at Interop Las Vegas, but also our full range of Omnipliance solutions will be a part of the InteropNet!

Preparing for Interop
Being a part of the Interop NOC is challenging in several ways. First, you are working in a research and development environment that has the most advanced wired and wireless technologies.

Second – and maybe the most challenging – is Interop vendors and attendees use as much bandwidth as possible to ensure that product demos go on without a hitch and to stay connected to the outside world via mobile devices. The number of devices deployed as well as the bandwidth needed to run the show makes operating a highly reliable, high performance network a challenge and the ability to troubleshoot and quickly resolve issues a high priority. This is where our real-time analysis and network forensics on both wired and wireless networks will play a crucial role both in finding and diagnosing any problem.

For the last two weeks, we’ve been working with our fellow NOC vendors and volunteers to create a working infrastructure and testing our Omnipliances interoperability with the other products in the NOC. Together, we helped enable a seamless, end-to-end network application monitoring, analysis and troubleshooting solution that is ready for the show, although our work has just begun.

During Interop
The WildPackets’ Professional Services team will be looking at the real-time health across all the network segments in a single view at Interop and ready to quickly troubleshoot any network issues. With leveraging our expert events and network forensic capabilities, we can easily detect any bandwidth hogs and maintain the high quality runtime of InteropNet.

For wireless, our Omnipliances will help validate the placement of access points and the signal strength. They will validate configuration and optimizations changes that network engineers may make during the show. For example, these changes may include increasing the signal strength of an Access Point (AP), changing a directional antenna, changing what types of clients can connect, or even changing how often an AP will beacon. Also, the Omnipliances can easily detect and investigate BYOD issues when wireless devices are in motion to maintain the high quality wireless experience at InteropNet.

If you want to hear more about our participation at Interop, leave us a comment or come say hello at booth 2059. You can also tour the NOC on Wednesday and Thursday, May 8 and 9.

How 802.11ac Improves Upon 802.11n

In the next few blog posts, we’ll be discussing 802.11ac and how it will help the wireless industry at large. To help set the foundation for blogs to come, we’re going to be discussing our favorite highlights of 802.11ac.

For the most part, 802.11ac is really a “lessons learned” from 802.11n. Below we break down the essential ways that 802.11ac has improved upon 802.11n and how it results in an amazing improvement in aggregate WLAN capacity.

More, and More Efficient, MIMO (Multiple Input Multiple Output)
802.11n has become the de facto wireless standard – and many people have moved to this new standard and are already seeing huge benefits. 802.11ac takes many of the new technologies introduced with 802.11n, including MIMO, and drives them even further.

In 802.11n, the maximum number of MIMO streams is four. Addition of MIMO streams creates a linear increase in overall throughput, and with 802.11ac the maximum number of MIMO streams is increased to eight. So with no other improvements (even though there ARE many more), 802.11ac would double the overall available throughput.

Along with an increase in the number of streams, 802.11ac also introduces higher encoding rates when converting digital traffic for RF modulation. This higher encoding rate results in an overall throughput improvement of over 40%, which is realized for each individual data stream.

As you can see, we’re already on our way to some significant improvements!

Smarter Channel Bonding
Channel bonding was also first introduced in 802.11n. In essence channel bonding creates new, data only channels that are wider than the existing 802.11 channel definitions. Specifically, a single 802.11 channel is approximately 20MHz wide. Channel bonding “steals” some space from adjacent channels and increases the overall channel width to, in the case of 802.11n, 40MHz. This effectively doubles the throughput for the data packets. All management packets are still sent using the standard 20MHz bandwidth and on standard channels to accommodate backward compatibility.

802.11ac increases the number of channels that can be bonded, creating even wider channels that can handle even greater throughput. Channel widths of 80MHz, and optionally 160MHz, have been added. Channel bonding is a bit of a double-edged sword, because although users benefit from the increased throughput, the number of channels available for use effectively decreases. This is often not an issue in consumer environments, where WLANs typically consist of a single AP and very little overlap with other adjacent WLANs (like your neighbor’s). In fact, this is an ideal case for greater channel bonding since only one channel is usually in use anyway, so why not maximize the bandwidth of that channel to take advantage of as much spectrum, and as much throughput, as you can? Channel bonding in enterprise environments can be a bit more tricky. 802.11ac tries to deal with this by limiting operation to only the 5GHz band, where the original channel allocation is wider, and more overall spectrum is available. But there can still be issues, and we’ll likely cover this in more detail in a future blog post.

So, if you’re keeping track, additional channel bonding in 802.11ac doubles or quadruples the maximum data throughput, offering yet another significant improvement!

Multi-User MIMO
Earlier we described how 802.11ac uses eight spatial streams, while 802.11n only uses four. But this is not the only MIMO improvement in 802.11ac.

Multi-User MIMO (or MU-MIMO) allows multiple stations to transmit or receive the exact same data simultaneously. For example, if you’re hosting a Super Bowl party and you want to have the game displayed on all your video screens (say two HDTV monitors and an iPad that can be moved around the house), 802.11ac can distribute this video stream simultaneously to all these devices. Without 802.11ac, even for an identical data stream, the wireless protocol required you to send the data stream to each device separately, and serially, thereby limiting the effective throughput for each individual device. In our Super Bowl example, and without 802.11ac, this means each device would actually see an effective throughput less than one third of the available throughput since the data would be sent three times, once for each individual device.

The tally of increased performance continues to grow by leaps and bounds, with MU-MIMO providing significant improvements in effective WLAN throughput.

Additional Updates
Additional improvements, including more efficient and effective use of beam forming (another optional feature) and other layer 1 and 2 changes, round out the list of substantial improvements. So, when the accounting is all done, the aggregate capacity of the WLAN grows from 600Mbps with an all-out implementation of 802.11n to 6.93Gbps with an all-out implementation of 802.11ac, better than a 10x improvement!

Stay tuned in the coming weeks as we translate these technical improvements into the real-world improvements we all hope to take advantage of as 802.11ac begins to roll out. First up will be improvements for mobile, battery-operated devices, including those we’ve become dependent on, like iPhones and Droids.

Best Practices in Planning Your Wireless Network

Laying out a wireless network can be tedious, and sometimes downright stressful. In multi-AP deployments (i.e. every enterprise deployment) the placement of one AP affects all others, so every tweak in AP positioning can be like bumping the first domino, causing the entire chain to fall and have to be set up again. That is why, when mapping out where to place APs and how many to use, it’s important to have a blueprint before taking on the task yourself.

This can be done in two fashions: automatically and manually. Both practices are relatively easy for wireless pros, but each has its strengths and weaknesses. When mapping out a network across multiple stories, or large open buildings like warehouses, it is best to automatically plan AP placement using a downloaded 3D map of your space and software specifically designed for this task, like Ekahau Site Survey. On the other hand, when planning out smaller networks, often times professionals find more satisfaction, and more control, in doing so manually.

We’ve outlined both best practices below, as well as next steps to follow to ensure that your network keeps running at peak performance.

Automatic Network Planning
For the less technical wireless professional, or for large scale deployments, automatic network planning software is the best way to map out where APs should be placed to optimize your network’s performance and the overall user experience. This process involves importing floor plans of the areas to be covered by the wireless network, specifying some key dimensions on the floor plan (so the program can determine the scale accurately), specifying key construction elements in your floor plan (wood vs. metal studs, wall materials, other structures not represented in the floor plan, etc.), and selecting the AP make(s) and model(s) you plan to deploy. Most software includes a database of AP features and capabilities for common manufacturers and model numbers, so it tries to do the very best job to maximize the potential of the equipment you plan to use. The software will then calculate the approximate locations and configurations for the APs on a virtual 3D map of your building. It will also provide a channel map (a channel assignment for each AP), making every effort to avoid co-channel interference between APs. Once the software has developed a proposed layout, you can make manual adjustments, for example, if some APs end up being located in undesirable or infeasible locations (no power, no network drop, etc.). This is where the real value comes in, because in an actual deployment a few tweaks like this causes the domino effect, but since you’re only dealing with software right now you can see the effect your manual change has without needing to do any other work.

You can also play “what if” with the software, trying different configuration parameters than those recommended, or even “trying out” equipment from different manufacturers to see if certain solutions have advantages over others. For a large deployment, the time savings with an automated approach are tremendous, and easily justify the cost of either the software purchase, or the services of a third-party to run the simulations for you.

Once you’re pretty confident of your deployment, you can lay out the network, and again leverage the software to perform a site survey, taking measurements at locations within the deployment to assess the accuracy of the original software layout and make other small adjustments to ensure the best WLAN configuration.

Manual Network Planning
This approach is better suited to the more seasoned wireless expert, and is typically best for smaller deployments. It still requires the use of software – any deployment of more than just a few APs has far too many variables to manage the entire process manually. Manual network planning is only “manual” in the sense that you place your APs on the building map yourself, possibly even choosing the channel layout yourself, and then letting the program calculate overall WLAN coverage, providing a “heat map” of expected signal strengths at all locations in the network, so you can see if your layout is acceptable before actually deploying any equipment. This approach is most often used when your choices for AP placement are limited. The software can optimize the AP settings to maximize overall performance based on your AP placement constraints. After you’ve settled on a design, the same site survey described above should be used to validate both the placement and the settings, with necessary adjustments being made along the way.

Ongoing Monitoring and Analysis
Once a network is up and running you need a different solution to perform day-to-day network monitoring and analysis. Monitoring solutions are used to track which stations are connected to which APs, the overall throughput each station is able to achieve, signal strength and noise measurements, and network problems like packet loss, latency, and device configuration issues. When problems are identified, you need to be able to drill down to the details of each station to AP connection, often down to the packet level, to determine the root cause of problems.

Using a combination of WLAN planning software and a WLAN monitoring and analysis solution, you will be ensured of both the best overall WLAN design possible, and well as a network that continually meets the demands of your ever-expanding wireless network user base, essentially eliminating the threat of one day toppling over all those WLAN dominos.