1. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Principles of High Performance Wi-Fi Brian Mason Director of Product Marketing Brian Mason Director of Product Marketing

2. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 2 Wi-Fi Needs High speed connectivity for fast transfer of large data files (e.g. CAD, simulation software, etc) Robust coverage for reliability on mission critical projects Pervasive availability for easy collaboration any where. Reliable enough to be considered suitable failover for wired networks Secure connectivity to entrust proprietary data

3. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Wi-Fi Nightmares 3

4. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Wi-Fi Nightmares 4

5. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Wi-Fi Nightmares 5

6. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 6 Wi-Fi Challenges 1.Higher User Density 2.Performance 3.Reliable Seamless coverage 4.Security 5.Resiliency

7. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 7 Wired Faced same problem 15 years ago Added bandwidth – Ethernet trumped ATM and Token Ring Dedicated Resources – Switches beat hubs Intelligence at the edge – Intelligent switches are the standard Easier Deployment – more ports, fewer devices

8. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 8 Wireless Following Wired’s lead Six Trends in wireless making this possible: 1. Standardization of 802.11n (Increased Bandwidth) 2. Move from 2.4GHz to 5GHz (Increased Bandwidth) 3. Multi-Radio devices (Greater Capacity) 4. Directional Antennas (Greater range, fewer devices) 5. Embedded Threat Sensors (Increased Security) 6. Integrated Spectrum Analyzer (Easier Troubleshooting)

9. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Should be ratified June 2009 Faster Up to 100 Mbps with first-gen pre-N products Up to 300 Mbps with 802.11n draft 2.0 products Ample bandwidth makes it easier for a single WLAN to support a mix of voice, video and data Farther More than 300 feet vs. 100 feet with 802.11a/b/g Potential for lower infrastructure costs because fewer access points (APs) required to blanket an area 802.11n: The Basics

10. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved More Robust MIMO technology mitigates interference and maintains broadband performance even with weak signals More Secure Wi-Fi Alliance certified 802.11n draft 2.0 products must include Wi-Fi Protected Access 2 (WPA2) 802.11n: The Basics

11. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 11 802.11n – Obtaining Higher Data Rates Spatial Multiplexing Source data stream split and sent over separate antennas at the same time Recombined at receiver using MIMO signal processing Doubles, triples, or quadruples the data rate depending on the number of transmit antennas used Channel Bonding Increasing the Bandwidth Bonds two 20MHz channels to a 40MHz channel Slightly more than doubles the bandwidth Phased channel operation: ability to jump between 20 and 40Mhz channels

12. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 12 802.11n – MAC Improvements Reducing Overhead Improves Efficiency Frame Aggregation Block ACKs Reduced Inter-frame spacing

13. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 802.11n Range and Data Rates Longer Range or Higher Data Rates Wi-Fi Certified data rates 300Mpbs Most compatible with 802.11a Backwards compatible with 802.11bg Channel Bonding Multiple Input/ Muliple Output (MIMO) Spactial Multiplexing

14. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 14 5GHz vs 2GHz Spectrum

15. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 15 802.11 Channels – Cell Planning 802.11b/g Channels Available = 3 Distance to cell with same channel is less than a single cell Sensitive to co-channel interference (from other cells on the same channel) If energy is weak, seen as interference If energy is strong, stations will defer Bleed-over retards higher data rates Greatly reduces overall network capacity 802.11a Channels Available = 23 High Performance: 8 times the capacity Far less interference from cells on same channel More channels to avoid interference

16. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 16 802.11 Channels – Interference Issues 802.11b/g uses the 2.4 GHz ISM band Common devices cause interference Bluetooth devices Cordless phones Microwave ovens X10 wireless video cameras HAM radio operators Interference collides with the intended signal Transmissions are garbled and data packets are retransmitted Reduced end-user throughput and increased latency of data traversing the RF network 802.11a uses the 5GHz UNII band Relatively interference free

17. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 17 802.11n Rates and Modes 802.11a/n (5GHz) 23 channels * 150Mbps = 3.4Gbps 802.11a (5GHz) 23 channels * 54Mbps = 1.2 Gbps 802.11g/n (2.4GHz) 3 channels * 150Mbps = 450 Mbps 802.11g (2.4GHz) 3 channels * 54Mbps = 162 Mbps 802.11b (2.4GHz) 3 channels * 11Mbps = 33 Mbps 150

18. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 18 Multi-Radio vs Dual-radio Architectures Multiple Radios in a single AP (i.e. an Array) = MORE CAPACITY - Traditional APs have one or two radios - New multi-radio architectures have up to 4, 8, or 16 radios in a single device - Each radio has fixed bandwidth - Each radio can support a limited number of users at one time In a classroom of 30 students a dual radio AP will have 15 students per radio Traditional AP: Multi-Radio In the same classroom an Array would just have 2 or 3 students per radio

19. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 19 Directional vs Omni-Directional Directional Antennas = GREATER RANGE Better antenna gain Better receiver sensitivity Allows fewer devices cover a larger area Typically 75% fewer devices and cable drops required

20. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 20 Distributed vs Centralized Distributed = HIGHER PERFORMANCE Packet Processing at edge Control plane at edge Policy and security enforcement at edge Encryption processing at edge Just like Ethernet Switching Central management Central Controller + Thin Aps Packet Processing at core Control plane at core Policy and security enforcement at core Encryption processing at core Central management Centralized ProcessingDistributed Processing

21. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Security Security Performance Use Line-rate Hardware Based Encryption AES (WPA2) is Best Hardware based encryption on client Best to Use a Single Encryption Mode per SSID Authentication: 802.1X RADIUS Servers should be local PMK Sharing = faster roaming Intrusion Detection Threats, Attacks, Compliance Neighboring Networks Requires: Dedicated Radio for RF Monitoring Time sharing radios for IDS reduces performance especially for voice You cant fix a problem if you don’t know there is a problem 21 Access Point / Array Authentication Server Ethernet Switch Hardware-Based Line-Speed Encryption Encryption Engine Dedicated Monitor Radio

22. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Wi-Fi Array The Xirrus Wi-Fi Array Single Device Superior Range and Capacity 75% Less Devices and Cabling Up to 16 Modular Radios 802.11n Upgradeable Advanced RF Management Redundant Radios and Ethernet Integrated Wi-Fi Switch Integrated Spectrum Analyzer Integrated Threat Monitor Line Speed Hardware-based Encryption Filtering and Firewalling Complete Suite of Management and Planning Tools Plan for the Success of your Wi-Fi Network! 22 Wi-Fi Sponsor ’06 & ‘07 Best Design of the Year B e s t S t a r t u p Array Controller Radio Modules Antennas

23. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved 23 The Future of Wi-Fi “The only effective way to deliver high- performance Wi-Fi is to have a centrally managed intelligent edge network – just like your wired networks do”

24. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Wi-Fi Reference Poster Series Xirrus Wi-Fi Reference Posters Register at: www.xirrus.com/library Email: posters@xirrus.com Posters in the Series 802.11a/b/g 802.11n Principles Wi-Fi Authentication Wi-Fi Encryption Wi-Fi Range Dynamics Wi-Fi Network Architectures Wi-Fi Cousins & Nephews High Performance Wi-Fi Also: Reference Poster Podcast Reference Poster Companion Guides Webinars White Papers Design Guides

25. Confidential Information ® 2008 Xirrus, Inc. All Rights Reserved Thanks Visit www.xirrus.com forwww.xirrus.com - Wi-Fi posters - 802.11n webcast and podcast - Best Practices and design guides - Wi-Fi gadgets and widgets