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Jay Botelho
Director of Product Management
WildPackets
[email protected]
Follow me @jaybotelho
802.11n Increased Speed, Increased Complexity
Show us your tweets! Use today’s webinar hashtag:
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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
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802.11n – Evolution or Revolution?
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802.11n – Evolution vs. Revolution?
• MIMO: Multiple Input – Multiple Output
• Channel Bonding
• Aggregation and Block Acknowledgements
• Short Guard Interval (SGI)
• Beam Forming
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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
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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
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MIMO Multiple Input, Multiple Output
• Multipath reduces the
signal strength of the data
transmission
• A second antenna is used
for ―spatial diversity‖
• Multipath still exists, but it
is also leveraged to send
multiple, independent data
streams
• Essentially 4x the
throughput
TX RX
01110001010
TX RX 01110001010
10010001010
11110001010
00000001010
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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/
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Aggregation
• A-MSDU
‒ Single MAC frame, multiple PDU
(Protocol Data Units)
‒ Processed by MAC layer as single entity
‒ De-aggregation required by receiver
• A-MPDU
‒ Multiple MAC frames
‒ Each MPDU encrypted/decrypted individually
‒ Requires Block Acknowledgement
http://mnet.cs.nthu.edu.tw/paper/tmlin/050923.pdf
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Block Acknowledgements
• Borrows ―windowing‖ technique from TCP/IP
• Acknowledges multiple frames with a single ACK
• Missing frames are retransmitted
• Can significantly reduce management overhead
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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
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Features vs. Performance vs.
Complexity
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Performance Per Feature
• MIMO
• Channel Bonding
• Block
Acknowledgements
• Aggregation
• Short Guard
Interval
• Beam Forming
802.11n – Are You Seeing It All?
Aruba Networks, 2008
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By The Numbers
http://www.bitcricket.com/downloads/Inside%20802.11n%20Wireless%20LANs.pdf
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Down To The Details (1, 2-Stream)
MCS
index
Spatial
streams
Modulation
type
Coding
rate
Data rate (Mbit/s)
20 MHz channel 40 MHz channel
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
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Down To The Details (3, 4-Stream)
MCS
index
Spatial
streams
Modulation
type
Coding
rate
Data rate (Mbit/s)
20 MHz channel 40 MHz channel
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
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3-Stream – How Available Is It?
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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
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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
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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
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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
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Available External Wi-Fi Adapters
3-Stream? 2
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Available APs
3-Stream? 13
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Employing 802.11n Features
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Jay’s Recommendations
802.11n Feature Greenfield
Deployment
Mixed Upgrade
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
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Monitoring and Analysis in
11n Environments
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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
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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
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Monitoring, Analyzing, Troubleshooting 11n
• Mixed modes
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Monitoring, Analyzing, Troubleshooting 11n
• Mixed modes
• Greater throughput
stresses wireless
analysis solutions
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Monitoring, Analyzing, Troubleshooting 11n
• Mixed modes
• Greater throughput
stresses wireless
analysis solutions
• New applications –
it’s a platform
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Multi-Channel Analysis
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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
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Wired and Wireless
• Security protocols and policy
• Rogue APs and clients
• Ad-hoc networks
• Wireless security attacks
• QoS configuration and use
• Signal strength
• Dropped packets and retries
• Tracking wireless packets onto the
wired network
• QoS configuration and use
• VPN/MPLS
• Application vs. network latency
Access
Point Router
Air-link
Private
Network
or the
Internet
Auth
Server
Ethernet Ethernet
WLAN
Controller
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Company Overview
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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
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Real-World Deployments
Education
Health Care / Retail
Financial
Telecom
Government
Technology
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Product Line Overview
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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
Product Line Overview
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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
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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
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Omnipliance Network Recorders Price/performance solutions for every application
Portable Edge Core
Ruggedized
Troubleshooting
Small Networks
Remote Offices
Datacenter Workhorse
Easily Expandable
Aluminum chassis / 17” LCD 1U rack mountable chassis 3U rack mountable chassis
Quad-Core Xeon 2.5GHz Quad-Core Intel Xeon
X3460 2.80Ghz
Two Quad-Core Intel Xeon
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
storage capacity
1TB SATA storage capacity 2TB SATA storage capacity
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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
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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
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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
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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
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Q&A
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#wp_80211n with any questions, comments, or feedback.
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Thank You!
WildPackets, Inc.
1340 Treat Boulevard, Suite 500
Walnut Creek, CA 94597
(925) 937-3200