Watch the full OnDemand Webcast: http://bit.ly/wcincreasing80211 Making the move to 802.11n? Though the rewards are significant, they come with a cost. The increased complexity of 802.11n can be a bit maddening, and it will definitely impact the way you design, monitor, and maintain your WLAN. MIMO? Channel bonding? Aggregation? If these terms aren’t currently part of your WLAN vocabulary, they certainly will be by the time you make the move. And even though the specification has been ratified for some time now, 802.11n hardware continues to evolve. Join us as we explore the number of MIMO streams, channel bonding, guard interval lengths, and other characteristics that define your WLAN capabilities. We’ll also characterize the current state of commercially available 802.11n hardware, arming you with the information you need to determine if, when, and how you want to make the move. In these slides, we will cover: - Key technologies that are new to 802.11n - The relative importance of each technology in contributing to increased performance - The current “state of the art” of commercially available 11n equipment What you will learn: - What new 11n technologies are most important to you - When to use the various 11n technologies - How to monitor and analyze WLANs – both mixed-mode and Greenfield 11n Watch the full webcast at: http://bit.ly/80211nIncreasedSpeedComplexity.

1. 802.11n
Increased Speed, Increased Complexity
Jay Botelho Show us your tweets!
Director of Product Management Use today’s webinar hashtag:
WildPackets
jbotelho@wildpackets.com #wp_80211n
Follow me @jaybotelho with any questions, comments, or feedback.
Follow us @wildpackets
© WildPackets, Inc. www.wildpackets.com

2. Agenda
• 802.11n – Evolution or Revolution?
• Features vs. Performance vs. Complexity
• 3-Stream – How Available Is It?
• Employing 802.11n Features
• Monitoring and Analysis in Mixed Environments
• Company Overview
• Product Line Overview
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 2

3. 802.11n – Evolution or Revolution?
© WildPackets, Inc. www.wildpackets.com

4. 802.11n – Evolution vs. Revolution?
• MIMO: Multiple Input – Multiple Output
• Channel Bonding
• Aggregation and Block Acknowledgements
• Short Guard Interval (SGI)
• Beam Forming
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 4

5. Example – Purdue University
• "The management of our wireless network, when you
boil it down, is three people. It's three busy people,
but not three suicidal people."
- Scott Ksander, Executive Director of Networks and Security
• 6,000 802.11n APs, 265 buildings, 10,000 users
• Using a controller-based architecture is a must
• Uses Cisco software for centralized monitoring but
requires specific trouble-shooting tools for the field
• 11n is a must – Purdue learned the hard way that
large lecture halls with 802.11bg APs could not
tolerate 600 students logging in at the same time
Source: http://searchnetworking.techtarget.com/news/article/0,289142,sid7_gci1373978,00.html
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 5

6. The Real World at Liberty University
• Multi-channel, IP-based video (IPTV) over wireless
• Provide roaming students with universal access to
multi-channel video
• Delivery of 15 live TV channels
• Liberty's campus channel as well as ABC, CBS, CNN,
ESPN, FOX, NBC, and a range of other broadcasters
• Serves 46,000 local/remote students and 2,600 FTEs
• Network includes more than 770 Aruba 802.11n
access points
Source: http://www.marketwire.com/press-release/Liberty-University-Launches-Campus-Wide-Wireless-
IPTV-Using-80211n-Wi-Fi-From-Aruba-NASDAQ-ARUN-1069662.htm
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 6

7. MIMO
Multiple Input, Multiple Output
TX RX
TX RX 01110001010
01110001010 10010001010
11110001010
00000001010
• Multipath reduces the • Multipath still exists, but it
signal strength of the data is also leveraged to send
transmission multiple, independent data
• A second antenna is used streams
for ―spatial diversity‖ • Essentially 4x the
throughput
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 7

8. Channel Bonding
• Creates a single 40 MHz channel from two adjacent
20 MHz channels
‒ More than doubles effective data rate
‒ 802.11n can use both 20 MHz or 40 MHz channels in both the
2.4 or 5 GHz band
http://wifijedi.com/2009/01/25/how-stuff-works-channel-bonding/
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 8

9. Aggregation
• A-MSDU • A-MPDU
‒ Single MAC frame, multiple PDU ‒ Multiple MAC frames
(Protocol Data Units) ‒ Each MPDU encrypted/decrypted individually
‒ Processed by MAC layer as single entity ‒ Requires Block Acknowledgement
‒ De-aggregation required by receiver
http://mnet.cs.nthu.edu.tw/paper/tmlin/050923.pdf
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 9

10. Block Acknowledgements
• Borrows ―windowing‖ technique from TCP/IP
• Acknowledges multiple frames with a single ACK
• Missing frames are retransmitted
• Can significantly reduce management overhead
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 10

11. Other Techniques
• Short Guard Interval (SGI)
‒ Guard interval: Amount of time between transmissions, needed
to prevent transmission overlap
‒ 802.11/a/b/g use 800 nanosecond guard interval
‒ SGI reduces the guard interval to 400 nanoseconds – 11%
performance improvement
• Beam Forming
‒ Optional part of 802.11n – not widely used yet
‒ Antenna arrays used to focus signal on area where receiver is
located
‒ Transmitter must keep track of where receiver is located
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 11

12. Features vs. Performance vs.
Complexity
© WildPackets, Inc. www.wildpackets.com

13. Performance Per Feature
• MIMO
• Channel Bonding
• Block
Acknowledgements
• Aggregation
• Short Guard
Interval
• Beam Forming
Aruba Networks, 2008
802.11n – Are You Seeing It All?
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 13

14. By The Numbers
http://www.bitcricket.com/downloads/Inside%20802.11n%20Wireless%20LANs.pdf
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 14

15. Down To The Details (1, 2-Stream)
Data rate (Mbit/s)
MCS Spatial Modulation Coding
20 MHz channel 40 MHz channel
index streams type rate
800 ns GI 400 ns GI 800 ns GI 400 ns GI
0 1 BPSK 1/2 6.50 7.20 13.50 15.00
1 1 QPSK 1/2 13.00 14.40 27.00 30.00
2 1 QPSK 3/4 19.50 21.70 40.50 45.00
3 1 16-QAM 1/2 26.00 28.90 54.00 60.00
4 1 16-QAM 3/4 39.00 43.30 81.00 90.00
5 1 64-QAM 2/3 52.00 57.80 108.00 120.00
6 1 64-QAM 3/4 58.50 65.00 121.50 135.00
7 1 64-QAM 5/6 65.00 72.20 135.00 150.00
8 2 BPSK 1/2 13.00 14.40 27.00 30.00
9 2 QPSK 1/2 26.00 28.90 54.00 60.00
10 2 QPSK 3/4 39.00 43.30 81.00 90.00
11 2 16-QAM 1/2 52.00 57.80 108.00 120.00
12 2 16-QAM 3/4 78.00 86.70 162.00 180.00
13 2 64-QAM 2/3 104.00 115.60 216.00 240.00
14 2 64-QAM 3/4 117.00 130.00 243.00 270.00
15 2 64-QAM 5/6 130.00 144.40 270.00 300.00
http://en.wikipedia.org/wiki/IEEE_802.11n-2009
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 15

16. Down To The Details (3, 4-Stream)
Data rate (Mbit/s)
MCS Spatial Modulation Coding
20 MHz channel 40 MHz channel
index streams type rate
800 ns GI 400 ns GI 800 ns GI 400 ns GI
16 3 BPSK 1/2 19.50 21.70 40.50 45.00
17 3 QPSK 1/2 39.00 43.30 81.00 90.00
18 3 QPSK 3/4 58.50 65.00 121.50 135.00
19 3 16-QAM 1/2 78.00 86.70 162.00 180.00
20 3 16-QAM 3/4 117.00 130.70 243.00 270.00
21 3 64-QAM 2/3 156.00 173.30 324.00 360.00
22 3 64-QAM 3/4 175.50 195.00 364.50 405.00
23 3 64-QAM 5/6 195.00 216.70 405.00 450.00
24 4 BPSK 1/2 26.00 28.80 54.00 60.00
25 4 QPSK 1/2 52.00 57.60 108.00 120.00
26 4 QPSK 3/4 78.00 86.80 162.00 180.00
27 4 16-QAM 1/2 104.00 115.60 216.00 240.00
28 4 16-QAM 3/4 156.00 173.20 324.00 360.00
29 4 64-QAM 2/3 208.00 231.20 432.00 480.00
30 4 64-QAM 3/4 234.00 260.00 486.00 540.00
31 4 64-QAM 5/6 260.00 288.80 540.00 600.00
http://en.wikipedia.org/wiki/IEEE_802.11n-2009
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 16

17. 3-Stream – How Available Is It?
© WildPackets, Inc. www.wildpackets.com

18. The Secret of ―NxM‖
• Each MIMO system is defined with NxM antenna
matrix
‒ N = # of Transmit antennas
‒ M = # of Receive antennas
‒ Ex. 3x3 AP means 3 transmit and 3 receive antenna
‒ The word chain is used to define this radio/antenna combination
• Each transmit antenna can transmit a uniquely
encoded data stream called a Spatial Stream (SS)
‒ Spatial streams sometimes written as “:x”
‒ 3x3:2 == 3 TX antennas, 3 RX antennas, 2 streams
• A system with N chains can support a maximum of N
spatial steams
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 18

19. What Are All These Antennas For?
• All antennas are equal, and do the same thing
‒ All antennas transmit
‒ All antennas receive
‒ All antennas serve the same bands
• Some antennas may transmit data (streams) while
some may be used for spatial diversity
• Some vendors have separate antennas for each band
‒ 5GHz and 2.4GHz are separated
• Some vendors have dual-band antennas
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 19

20. Choosing a Wireless Adapter for Capture
• Every value in ―NxM:x‖ is critical
‒ N = # of Transmit antennas = same as most capable AP
‒ M = # of Receive antennas = same as most capable AP
‒ :x = # of Streams = same as most capable AP
• A 3x3:2 wireless adapter (the most commonly
available today) CANNOT capture 3x3:3 traffic
• A 3x3:3 wireless adapter CAN capture 3x3:2 traffic
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 20

21. Availability
• Must distinguish between APs and wireless adapters
• ―NxM‖ = 3x3 is pretty easy to find
‒ Both for APs and wireless adapters
• 3x3:3 is difficult to find
‒ Look for 450 MHz throughput – not many out there
‒ APs are a bit easier to find
‒ Wireless adapters are much more difficult to find
• Form factor is also an issue
‒ PCIe cards (internal laptop adapters) will be first to market
‒ USB devices coming slowly – power is an issue in “:3” devices
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 21

22. Available External Wi-Fi Adapters
2 3-Stream?
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 22

23. Available APs
13 3-Stream?
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 23

24. Employing 802.11n Features
© WildPackets, Inc. www.wildpackets.com

25. Jay’s Recommendations
802.11n Feature Greenfield Mixed Upgrade
Deployment
2-Stream
3-Stream
40MHz (Channel Bonding) * 5 GHz Only
Aggregation (AMPDU/AMSDU) ** **
Short Guard Interval ** **
Beam Forming
* Remember, you probably have neighbors
** This may not be something you can control
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 25

26. Monitoring and Analysis in
11n Environments
© WildPackets, Inc. www.wildpackets.com

27. Greenfield 802.11n
• Completely understand your environment
‒ Greenfield …, really?
‒ NxM:x – both for all APs and all wireless clients
‒ Usage of channel bonding, aggregation, etc.
• Assess availability of hardware available for wireless
data capture
‒ Must cover cross-section of AP and client NxM:x
‒ Sensitivity of wireless adapters used for capture
‒ External antenna connections are beneficial
• Choose data capture parameters that match your
environment
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 27

28. Mixed Environments
• Completely understand your environment
‒ Greenfield …, really?
‒ NxM:x – both for all APs and all wireless clients
‒ Usage of channel bonding, aggregation, etc.
• Assess availability of hardware available for wireless
data capture
‒ Must cover cross-section of AP and client NxM:x
‒ Sensitivity of wireless adapters used for capture
‒ External antenna connections are beneficial
• Choose data capture parameters that match your
environment
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 28

29. Monitoring, Analyzing, Troubleshooting 11n
• Mixed modes
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 29

30. Monitoring, Analyzing, Troubleshooting 11n
• Mixed modes
• Greater throughput
stresses wireless
analysis solutions
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 30

31. Monitoring, Analyzing, Troubleshooting 11n
• Mixed modes
• Greater throughput
stresses wireless
analysis solutions
• New applications –
it’s a platform
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 31

32. Multi-Channel Analysis
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 32

33. Wireless Roaming
• Campus-wide deployments
imply frequent roaming
• Roaming is the cause of many
wireless issues
• Voice and video are especially
sensitive
• Roaming analysis requires
detailed and accurate
measurements from many
perspectives
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 33

34. Wired and Wireless
Private
Access WLAN Auth
Router Network
Point Controller or the Server
Internet
Air-link Ethernet Ethernet
• Security protocols and policy • Tracking wireless packets onto the
• Rogue APs and clients wired network
• Ad-hoc networks • QoS configuration and use
• Wireless security attacks • VPN/MPLS
• QoS configuration and use • Application vs. network latency
• Signal strength
• Dropped packets and retries
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 34

35. Company Overview
© WildPackets, Inc. www.wildpackets.com

36. Corporate Background
• Experts in network monitoring, analysis, and troubleshooting
‒ Founded: 1990 / Headquarters: Walnut Creek, CA
‒ Offices throughout the US, EMEA, and APAC
• Our customers are leading edge organizations
‒ Mid-market, and enterprise lines of business
‒ Financial, manufacturing, ISPs, major federal agencies,
state and local governments, and universities
‒ Over 7,000 customers / 60+ countries / 80% of Fortune 1,000
• Award-winning solutions that improve network performance
‒ Internet Telephony, Network Magazine, Network Computing Awards
‒ United States Patent 5,787,253 issued July 28, 1998
• Different approach to maintaining availability of network services
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 36

37. Real-World Deployments
Education Financial Government
Health Care / Retail Telecom Technology
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 37

38. Product Line Overview
© WildPackets, Inc. www.wildpackets.com

39. Product Line Overview
OmniPeek/Compass
Enterprise Packet Capture, Decode and Analysis
• 10/100/1000 Ethernet, Wireless, WAN, 10G
• Portable capture and OmniEngine console
• VoIP analysis and call playback
Omnipliance / TimeLine
Distributed Enterprise Network Forensics
• Packet capture and real-time analysis
• Stream-to-disk for forensics analysis
• Integrated OmniAdapter network analysis cards
WatchPoint
Centralized Enterprise Network Monitoring Appliance
• Aggregation and graphical display of network data
• WildPackets OmniEngines
• NetFlow and sFlow
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 40

40. OmniPeek Network Analyzer
• OmniEngine Manager
– Connect and configure distributed OmniEngines/Omnipliances
• Comprehensive dashboards present network traffic in real-time
– Vital statistics and graphs display trends on network and application
performance
– Visual peer-map shows conversations and protocols
– Intuitive drill-down for root-cause analysis of performance bottlenecks
• Visual Expert diagnosis speeds problem resolution
– Packet and Payload visualizers provide business-centric views
• Automated analytics and problem detection 24/7
– Easily create filters, triggers, scripting, advanced alarms and alerts
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 41

41. Omnipliance Network Recorders
• Captures and analyzes all network traffic 24x7
– Runs our OmniEngine software probe
– Generates vital statistics on network and application performance
– Intuitive root-cause analysis of performance bottlenecks
• Expert analysis speeds problem resolution
– Fault analysis, statistical analysis, and independent notification
• Multiple Issue Digital Forensics
– Real-time and post capture data mining for compliance and troubleshooting
• Intelligent data transport
– Network data analyzed locally
– Detailed analysis passed to OmniPeek on demand
– Summary statistics sent to WatchPoint for long term trending and reporting
– Efficient use of network bandwidth
• User-Extensible Platform
– Plug-in architecture and SDK
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 42

42. Omnipliance Network Recorders
Price/performance solutions for every application
Portable Edge Core
Ruggedized Small Networks Datacenter Workhorse
Troubleshooting Remote Offices Easily Expandable
Aluminum chassis / 17” LCD 1U rack mountable chassis 3U rack mountable chassis
Quad-Core Xeon 2.5GHz Quad-Core Intel Xeon Two Quad-Core Intel Xeon
X3460 2.80Ghz E5530 2.4Ghz
4GB RAM 4GB RAM 6GB RAM
2 PCI-E Slots 2 PCI-E Slots 4 PCI-E Slots
2 Built-in Ethernet Ports 2 Built-in Ethernet Ports 2 Built-in Ethernet Ports
500GB and 2.5TB SATA 1TB SATA storage capacity 2TB SATA storage capacity
storage capacity
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 43

43. TimeLine
• Fastest network recording and real-time statistical
display — simultaneously
‒ 11.7Gbps sustained capture with zero packet loss
‒ Network statistics display in TimeLine visualization format
• Rapid, intuitive forensics search and retrieval
‒ Historical network traffic analysis and quick data rewinding
‒ Several pre-defined forensics search templates making
searches easy and fast
• A natural extension to the WildPackets product line
• Turnkey bundled solution
‒ Appliance + OmniEngine, OmniAdapter, OmniPeek Connect
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 44

44. TimeLine
For the most demanding network analysis tasks
TimeLine
10g Network Forensics
3U rack mountable chassis
Two Quad-Core Intel Xeon 5560 2.8Ghz
18GB RAM
4 PCI-E Slots
2 Built-in Ethernet Ports
8/16/32TB SATA storage capacity
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 45

45. WatchPoint
Centralized Monitoring for Distributed Enterprise Networks
• High-level, aggregated
view of all network
segments
– Monitor per campus, per
region, per country
• Wide range of network
data
– NetFlow, sFlow, OmniFlow
• Web-based, customizable
network dashboards
• Flexible detailed reports
• Omnipliances must be
configured for continuous
capture
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 46

46. WildPackets Key Differentiators
• Visual Expert Intelligence with Intuitive Drill-down
– Let computer do the hard work, and return results, real-time
– Packet / Payload Visualizers are faster than packet-per-packet diagnostics
– Experts and analytics can be memorized and automated
• Automated Capture Analytics
– Filters, triggers, scripting and advanced alarming system combine to provide
automated network problem detection 24x7
• Multiple Issue Network Forensics
– Can be tracked by one or more people simultaneously
– Real-time or post capture
• User-Extensible Platform
– Plug-in architecture and SDK
• Aggregated Network Views and Reporting
– NetFlow, sFlow, and OmniFlow
802.11n – Increased Speed, Increased Complexity © WildPackets, Inc. 47

47. Q&A
Show us your tweets!
Use today’s webinar hashtag: Follow us on SlideShare!
Check out today’s slides on SlideShare
#wp_80211n www.slideshare.net/wildpackets
with any questions, comments, or feedback.
Follow us @wildpackets
© WildPackets, Inc. www.wildpackets.com

48. Thank You!
WildPackets, Inc.
1340 Treat Boulevard, Suite 500
Walnut Creek, CA 94597
(925) 937-3200
© WildPackets, Inc. www.wildpackets.com