Monday, October 14, 2013

Three Wireless USB Adapters in Every Hub, and Omnipeek On Every Laptop #WFD5

Tim McCreery President and CEO of WildPackets presented the company history to the Wireless Field Day 5 delegates. Wildpackets was founded in 1990, and now their customer base spans 60+ countries and over 7,000 customers.

Jay Botelho Director of Product Management spoke next, and gave us the WildPackets technical history.
  • First to support data capture and analysis of 802.11ac traffic
  • The most comprehensive voice over wifi analysis
  • Only application to support remote data capture from commercial enterprise access points
  • Best application for distributed networks with remote 24x7 real-time analysis
Since the last time WildPackets presented at WFD4, they've since brought to market full 802.11ac support and data captures from locally-attached or remote access points.

The demonstration of the 802.11ac capture was interesting in that copies of OmniPeek and 802.11ac adapters were gifted to the delegates in order for them to generate 802.11ac traffic in the presentation room. OmniPeek only has drivers for the Ralink chipset wireless adapters at this time, but they should have a two stream adapter supported by the end of this year.

Per Jay Botelho, trusting RSSI reporting from access points is iffy since vendors apply RSSI values differently. WildPackets does some analysis work on the capture that is RSSI, and they have to do some work to convert that to dBi or a percentage value.

OmniPeek has new columns added to it to simplify analysis of an 802.11ac capture:
  • MCS value
  • Spatial streams
  • Bandwidth used
  • Data rate
Using multiple adapters to capture data is key in analyzing client roaming in any wireless network. When Jay listed the channels his test network was configured for (2, 6 and 10) I was concerned, since these are not non-overlapping channels. I do not know if this was just for testing purposes that these channels were used, but it isn't an optimal configuration.

  • Top pane = flows categorized by application
  • bottom pane = problems detected
WildPackets is currently running a special discount on their Mobile WLAN Analyzer bundle. The bundle includes OmniPeek Professional and 3 OmniWiFi USB WLAN (802.11a/b/g/n) adapters. The $900 discount is only good through 10/31/2013.

Tuesday, October 1, 2013

MU-MIMO They're not calling you names, they're speeding up your Wi-Fi! #Aerohive #WFD5


The thing I always vividly remember from an Aerohive session at Wireless Field Day, is the presentation by Matthew Gast. I love how he intertwines fun facts and figures into a slide deck AND uses matrix math to explain things that are still (somewhat) theoretical in nature.

At the WFD5 eventMatthew Gast presented on MU-MIMO in 802.11ac. I tried to take notes, but the  information flow was more than my brain buffer can process in real-time.

802.11ac Wave-2 and its enablers
  • explicit beamforming in 802.11ac
  • matrix math
  • implementation
  • null steering
  • acknowledgement and queueing
4 features of 802.11ac
  • wider channels (80 & 160MHz)
  • more spatial streams (up to 8 in a single user tx, 4 in a multi-user tx)
  • 256-QAM
  • downlink MU-MIMO
null data packets
  • not even a L2 construct
  • it's a phy layer data plane to describe the way the energy will be steered
Multiple devices connected at the 64 QAM rates will be able to send/receive more data than a single 256 QAM device will tx/rx.

Several matrices are used in matrix math:
  • H is the channel matrix that describes the path between transmitter and receiver
  • Q is the steering matrix that alters the distribution of energy along a path
  • V is the feedback matrix, sent as part of the measurement process to derive Q
The feedback loop based on speeds now is "Did you get an ACK or not?", it's not a matrix describing the connectivity. You can mix data rates inside a feedback matrix data result.

The block ack protocol is used when transmitting to multiple devices at the same time. This is a layer on top of sending beamformed frames. Data rates within a beamformed frame can be mixed. Block ACKs get used as a distributed acknowledgment system along with the RTS-CTS mechanism.

Multi-user MIMO is trading total overall throughput for individual peak throughput, and only works downstream.

The GCMP encryption requires AES but has fewer trips through the AES block and is still only optional in 802.11ac. 

I know all of that is quite a mouthful of acronyms! If you haven't watched the Aerohive presentation series, you'd be doing yourself a favor if you did.

Aerohive ID Manager Demonstration at WFD5 from Stephen Foskett on Vimeo.

Aerohive Client Management Demonstration from Stephen Foskett on Vimeo.

Aerohive Application Visibility and Control Demonstration from Stephen Foskett on Vimeo.

Aerohive Application Visibility and Control Presentation at WFD5 from Stephen Foskett on Vimeo.