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Guest Blog: Migrating High Density University Networks to 802.11ac

Editor’s Note: This is a guest post by Joe Rogers, Associate Director of Network Engineering for the University of South Florida (USF). Hear Joe speak about his experiences with next-generation wireless in high density environments on next Tuesday’s webinar:  ”Migrating Enterprise Networks to 802.11ac” at 10am PST (Dec 17) (Register here)

Joe RogersJoe Rogers is the Associate Director of Network Engineering for the University of South Florida.  He is a graduate of USF’s Computer Science and Engineering program and has worked as a network engineer at USF for the past 20 years.  He is currently responsible for all aspects of USF’s network which provides connectivity to over 100k devices across three campuses.  He’s held a CCIE routing and switching certification since 1999.  When not working, he’s an avid mountain biker (if you can call it “mountain” biking when you live in Florida).

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Universities face some of the most complex design challenges in wireless networking.  Our user population is highly mobile, bandwidth-hungry, and often simultaneously using at least two wireless devices in rooms with hundreds of their classmates.  The wireless network isn’t simply a convenience to them.  It’s critical to their educational success as many of the students are taking tests or working on assignments across the network.

At the University of South Florida, we support over 20,000 concurrent wireless users on our network of over 4,000 access points.  We have more than 90,000 unique devices registered this semester.  Our biggest challenge is designing the wireless network for the device densities in our large classrooms and popular study areas.  In these locations, we often have a thousand devices in a few hundred square feet of space.

We heavily rely on band select to place as many devices as possible on 5Ghz where more channels are available.  Unfortunately many devices such as older tablets and smart phones simply don’t have an 802.11a/n radio.  So we must carefully RF engineer the environment with smaller cells to provide the necessary coverage density. Read More »

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MegaTrends: New Video Services and Their Potential Impact on Your Network – Part 2

In the first part we discussed how video services are evolving within enterprise networks. Content may be sourced from internal servers, BYOD end points or external content providers, thereby creating a mix of managed and unmanaged services. This has led not only to growth in traffic, but also a competition for actual resources between the different types of services.

We have discussed how these services are evolving, now moving to a per application, per session model which ensures that specific resources are allocated depending on the nature of the usage. Tools such as those provided by the medianet architecture, combined with changes in defaulting all traffic within the VPN session back to the corporate network, contribute to this evolution in session management.

Once again, we turn to Thomas Kernen to provide some insight into how recent technology improvements are designed to help with managing video traffic growth and enabling better content distribution models.

Read More »

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Miercom: Cisco Aironet AP3702i

Cisco’s newest 802.11ac product, the Aironet 3700 Series Access Point is now orderable and shipping in the next few weeks.  The AP 3700 features an integrated 11ac radio with a 4x4 architecture and Cisco’s High-Density Experience (HDX) Technology.  HDX is a suite of features specific to the AP 3700 that delivers the best possible user experience, especially in high client density networks.  HDX is enabled by a combination of  hardware and software features on the AP 3700, features including:

  • CleanAir 80 MHz – Interference detection and mitigation
  • ClientLink 3.0 – RF link quality
  • Smart Roam – Intelligent roaming handoff
  • Turbo Performance – Performance with high client density

Aruba recently launched their 802.11ac access point, the AP-220 series, featuring a 3x3 design.

Miercom recently published a third-party evaluation of the performance between the AP 3702i and the AP-225.  The report consists of a diverse range of test cases meant to gauge real-world performance of the access points.  The tests include; multi-client performance, single client rate vs. range, performance in the presence of interference, and performance on reduced power.  Here are some of the highlights from the report.

Multi-Client Performance

The AP 3700 performed very well in the multi-client performance test, thanks impart to HDX Turbo Performance.  With 60 clients, the AP 3702i had a 6x performance advantage over the AP-225.  The AP-225 struggled to serve all the clients and only mustered 40 Mbps total.  The AP 3702i was able to transmit a healthy 236 Mbps, while maintaining fair throughput to each client.

The test consisted of 60 11ac clients, all associated to the 5 GHz radio.  The clients used were 10 Dell E6430 laptops with Broadcom 4360 three spatial-stream chips, 20 Apple Macbook Air two spatial-stream laptops, and 30 Dell E6430 laptops with Intel 7260 two spatial-stream chips.  Clients were setup in an open office environment surrounding the AP.  Distances varied from 10’ to 50’.

1-Mulit-Client Read More »

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6 Tips for High Density Network Design

The guys from No Strings Attached Show just published their podcast we sponsored featuring Jim Florwick yesterday and already the verdict is in: Jim Florwick is awesome.

For those of you who haven’t had the chance to download the podcast yet (What are you waiting for?! Download  podcast) or you have a few extra minutes to scan a short blog to decide whether or not you want to download the podcast, I asked Jim what his key takeaways are when it comes to high density design.

Here are Jim Florwick’s 6 tips for HD network design (for the REAL meat, tune into the podcast):

  1. High density client environments are quite common with today’s users being very connected – today’s users are always connected.  With planning, this can be managed quite successfully.  Understand the limitations, be aware of how legacy requirements will affect the outcome, and set expectations accordingly. Efficiency is key and removing some of the blockers (legacy) first is essential.
  2. 802.11ac represents another quantum leap forward in technology and will eventually allow a much richer user experience.   It is a transition that must be managed and balanced against your current mission requirements.  Evaluate channel/bandwidth requirements carefully.  Monitor the mix of client devices operating in your environment and update frequently. Read More »

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Deploying, Testing, and Tuning 802.11ac

By now you’ve probably heard quite a bit about the newest generation of Wi-Fi, 802.11ac.  I’ll save you the gory details, just know it’s about 3x faster than 802.11n and will help to improve the capacity of your network. Jameson Blandford and I were recently guests on the No Strings Attached Show podcast with Blake Krone and Samuel Clements (Click to listen to the podcast).

I wanted to follow up the podcast with a blog to go over considerations for deploying, testing, and tuning 802.11ac.

Considerations for deploying 802.11ac

Switching infrastructure

The first question you’ll want to ask yourself, is, if your switching infrastructure can handle 11ac?  The answer probably is, yes.  The things to consider are the port speed and power-over-Ethernet (PoE) capabilities.  You’ll want the access point to have a gigabit uplink to the switch.  Each 11ac access point could potentially dump several hundred megabits per second of traffic onto your wired network.  It’s also not a bad idea to have 10 Gig uplinks on your access switches to distribution or your core.  If you have even just a couple access points on a single access switch, you may quickly find yourself wishing you had 10 Gig uplinks.

Next you’ll need to consider how you will power the access points.  If you are like the majority of our customers, you will use PoE from your switches.  While 11ac access points require 802.3at (PoE+) for full functionality, the Aironet 3700 will run happily on standard 802.3af PoE.  In fact, it remains 3 spatial-streams on both radios, so performance does not suffer because you have a PoE infrastructure.

Will you deploy 80 MHz channels? Read More »

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