1 / 44

Technology for High Performance WLANs

Technology for High Performance WLANs. Serving The Needs Of Higher Education. Agenda. Meru Networks – Our Mission Why 802.11 WLANs require QoS for Voice and Data Meru’s QoS Architecture Comparing QoS Solutions Converged Network Case Study High Performance b/g Network Co-Existence

berk-holt
Télécharger la présentation

Technology for High Performance WLANs

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Technology for High Performance WLANs Serving The Needs Of Higher Education

  2. Agenda • Meru Networks – Our Mission • Why 802.11 WLANs require QoS for Voice and Data • Meru’s QoS Architecture • Comparing QoS Solutions • Converged Network Case Study • High Performance b/g Network Co-Existence • Location Based Services

  3. Our Mission Design and manufacture 3rd generation WLAN (Wi-Fi ) solutions for voice & data 5x Number of Voice Calls QoS High Performance: With Meru Air Traffic Control Technology 5x Number of Active Users High Density 0 Loss - Handoff Transparent Mobility Zero Configuration Easy Deployment & Management Multi-layers Comprehensive Security

  4. Meru Wireless LAN Infrastructure Products Meru AP AP Virtual AP AP Meru Controller • Coordinated Access Points • Over-the-Air QoS • Contention management • Controller • Centralized appliance for management and security • RF Interference Management • Built-in application Flow-Detectors e.g. SIP, H.323, Cisco Skinny, Spectralink SVP • Location Services Floor 2 Floor 1 L2 / L3Backbone Data Center

  5. Wireless LAN Evolution Stand Alone Pervasive Multi-site • Voice and Data • Business applications • Primary connectivity • Video emerging • Email, Web • Email, Web from different locations • Stand-aloneAccess Points • Centralized security and management • High Density • Application QoS • Transparent mobility • Full network integration Number of Clients and Coverage Applications Products / Technology

  6. Enterprise WLAN Product Evolution 2000-01 2002-3 2003-4 1st Generation 2nd Generation 3rd Generation Meru Generation 2 + RF Intelligence High Density QoS Zero Handoff Cisco 1200+SWAN Symbol Aruba, Trapeze, Airespace … Services / Scale Coordinated AP’s Central Switch/Appliance Cisco 350 Proxim Linksys Generation 1 + Central Management Security Basic Connectivity Aggregated AP’s Central Switch/ Appliance Stand-alone APs

  7. University WLAN Requirements • High Density • Lecture halls, classrooms, memorial unions, etc • High Mobility • Students, faculty, visitors – constant movement • Data, Voice, and Video • Data today • Voice emerging – soft phones, dual mode cell phones • Video – lecture content, video presentations, etc. • Integrated Security • Student / faculty / guest security profiles • Integration with network access control • Location based security

  8. WLAN Architectures “Stand Alone” or Fat” AP “Intelligent” AP “Thin” or “Fit” AP WLAN Switch / Controller WLAN Switch / Controller LAN Switch Overlay WLAN network, distributed intelligence, centralized control Architecture Stand alone APs, Centralized or Distributed Management Centralized intelligence RF coordination, simple deployment, scaleable, central management Benefits Simple implementation for a few access points, Centralized Management Scaleable, central management Medium & large enterprise Target Markets SOHO, Medium & large enterprise Medium & large enterprise

  9. Key Requirements WLANs QoS High Density Transparent Mobility Easy Deployment & Management Security With Standard WiFi Clients Priority for Voice Calls, Video Air Traffic Control Technology Capacity for Active Users Zero Loss Handoff Take Control of the Converged WLAN

  10. Issues for Voice & Data over Wi-Fi • Unpredictable behavior over-the-air • Random allocation of air time • Poor performance • Low user density • Low number of voice calls, call quality • Handoff • Security • Difficult to install • Difficult to manage

  11. The 4 fundamental problems that must be solved to achieve enterprise level performance for high density Voice and Data for Wi-Fi networks: 802.11 Challenges for Voice & Data 1. Single Cell Contention 2. Contention Across Cells 3. Jitter and Volatile Bandwidth Allocation 4. Slow Handoff

  12. Problem 1: Contention within Single Cell 11 Baseband + Protocol Overhead 8 Total Bandwidth at Peak (Mbps) 5 Contention Loss Today’s APPerformance 1 20 3 Number of Active Users S I Air = Shared Medium I I R • Multiple clients contend for the same shared medium • While transmitting sender cannot listen for collisions • As number of calls goes up, collisions increase • Collisions cause clients to backoff • Backoff slows down network • Requires more than scheduling

  13. Problem 2: Co-Channel Interference Across Multiple Cells 5.5/11 Mbps 1 Mbps Receive Signal at AP CS Distance Mbps Cellsize Interference Range Is Much Larger Than Communications Range Collision Domain Interference Domain

  14. Problem 3: Jitter & Bandwidth Allocation 1 AP + 20 Clients Throughput Channel Access with Today’s 802.11 AP 12 10 8 6 4 2 5.36 5.38 5.4 5.42 5.44 5.46 5.48 5.5 5.52 5.54 5.56 Time (Sec) Channel • As number of calls goes up: • Random channel access by clients causes latency & jitter • AP gets less bandwidth (only 1/nth of channel) • Erratic, unfair access over short term intervals (completely starved 2 clients)

  15. Problem 4: Slow Handoff Across Cells BSSID = A BSSID = B 01:00 100ms – 1 sec between handoff • Beacon and Probes to join available ESSID • 802.11 Association and Authentication process • 802.1X Authentication or any other type of security authentications (includes Radius or other AAA servers) • IP address assignment

  16. Meru Networks - QoS Architecture • Global knowledge of interference and resource usage at AP’s including knowledge of clients • Time-based accounting, not bandwidth-based • Inter-cell Coordination Global RF Resource Knowledge + Application Flow Detection • Deep packet inspection for understanding resource requirements of Application (e.g. SIP/Codec) Meru QoS Algorithms + Admission Control • Resource management + Per-flow Scheduling • Uplink and Downlink accounting of packets / expected packets • Reservation-based QoS + • Virtual carrier sense for uplink reservation/QoS • Contention-free periods and contention periods. Control Mechanismsin 802.11 Standard

  17. Meru Networks - Air Traffic Control Contention Management Algorithms Contention Suppression for QoS Flow Virtual MAC for Zero Handoff • Centralized Control • - Global Policies • - Global Coordination • Central RF Intelligence • App Flow Inspection MERU MAC - Local Governance - Dynamic QoS Flow Recognition - Distributed Rogue Detection & Mitigation Performed in Controller Performed in the Access Point Voice Client

  18. Comparing Control of the AirHow Meru Delivers Over-the-Air QoS Mgmt (Auth/Assoc/Probe) Beaconing Packet Fragmentation Scheduling/Queuing Lower MAC (CSMA/CA) PHY RF Meru AP Other APs • Access to the Lower MAC is critical to provide QoS • Decisions need to be made at microsecond level based on prior packet air conditions • Other AP’s queue packets asynchronously requiring decisions to be made several time intervals prior to transmission Reference-design AP Meru AP (with Meru MAC) Asynchronous Interface Between SW And MAC/PHY Sychronous Interface IntegratedMAC/PHY 802.11 Phy/RF

  19. Air Traffic Control - The Result Application Flows with Over-the-Air QoS Channel Access with Meru AP for QoS Flows C12 C10 C8 C6 C4 AP 5.36 5.38 5.4 5.42 5.44 5.46 5.48 5.5 5.52 5.54 5.56 Time (Sec) Meru AP • Predictable channel access • Predictable and low jitter • Support for higher number of clients

  20. Meru Air Traffic Control Technology 5x More Users Active Users Per AP 100+ Peak Aggregate Throughput Meru AP Performance 11 5X 8 5 20-25 Contention Loss Total Bandwidth at Peak (Mbps) Today Meru Today’s APPerformance 1 3 20-25 Number of Active Users

  21. Meru Air Traffic Control Technology Over-The-Air QoS: 5X More Voice Calls ~20-30 ~5-8 Standards-basedOver-the-Air QoS Over-the-air QoS Wired QoS Wired QoS AP AP Voice QualityMOS Score 4.0+ Generic Access Point + Standard Client Meru AP + Standard Client Data and voice typically on Separate channels/network Converged Network - voice and data on same channels

  22. Meru Quality of Service - Results 1 Meru AP + 20 Clients 1 AP + 20 Clients Throughput Throughput • Industry leading aggregate throughput at density • Predictable, uniformly fair throughput across all clients • Other AP’s erratic, unfair access over short term intervals completely starved 2 clients • 4X less loss rate (2% - 2.5%) • Versus other AP’s 8% loss rate

  23. Meru Air Traffic Control Technology Results - Zero Loss Handoff Virtual AP Architecture Today’s WLAN BSSID = M BSSID = M BSSID = A BSSID = B 00:00 01:00 No Handoff For Client 100ms – 1 sec between handoff Meru WLAN

  24. Meru Quality of Service - Summary • Works with all standard 802.11 Wi-Fi clients • Fine grained upstream and downstream over-the-air QoS with easy provisioning • Voice flow detectors (SIP, H.323, Vocera, Spectralink, Cisco) • Real-time highest priority • Application QoS Rules • Real-time, user-configurable rules • Client Fairness • 8 priority queues • Optimized throughput with Meru Air Traffic Control algorithms for predictable performance

  25. How Meru Over-the-Air QoS Compares to Others

  26. Customer Case Study

  27. “ Jackson Memorial Hospital A Meru Customer Success Story University of Miami Creating a Wireless LAN with better utilization across different applications is the right move for companies today. Enterprises require third generation Wireless LAN products with coordinated Access Points that permit greater scalability and centralized management. This will lead to a reduction in the overall costs of wireless infrastructure while improving performance. Rachna Ahlawat, Principal Analyst, Gartner Inc. ”

  28. The Jackson Memorial Hospital Wi-Fi Challenge Key Requirements Why Other Systems Fall Short • Inability to manage contention needed to support high density environments • Cannot operate on a single channel to avoid interference with outdoor AP • Unable to deliver over-the-air QoS needed for mission-critical applications • An indoor WLAN solution that could reliably co-exist with its existing outdoor AP’s • Future-proof system to support data today and voice in the future. • Support for high user density and broad range of devices

  29. Single Channel Deployment Leverage Existing Wired & Wireless Investments PAC Building Network Admin Building Floor 7 Meru AP Laptops Floor 6 Cisco Catalyst Switch Tablet PCs Floor 5 PDAs Virtual AP Outdoor Floor 4 WiFiPhones Cisco Catalyst 6500 Floor 3 Outdoor AP Cisco Catalyst Switch VoceraBadges Floor 2 Laptops Data Center NetscreenSSL VPN MeruController VoceraSystem Server PBX • Meru system seamlessly connected to existing wired Cisco switches and works with any standard 802.11 client (phone, pda, laptops) • Dynamic over-the-air QoS supports reliable data services today and high-performance voice and video in the future

  30. High Performance b/g Network Co-Existence

  31. Why 802.11 b/g Co-Existence? • Backwards compatibility of b clients • Large and growing installed base of b clients (Millions) • Utilize same AP infrastructure • No new AP installations • No RF re-planning • Higher channel efficiency for g networks • Leverages the g network speed – 54 Mbps

  32. The b/g Co-Existence Problems • Significant Co-Channel interference • Only 3 spectrally independent channels • Coverage required for high data rates • 802.11b slows down g clients • g client throughput reduced by 50%+

  33. 802.11b Slows g Clients • b client preamble and header impact control and data periods for g clients • Significant reduction in data rate – greater than 50% 802.11b Only CCK Preamble PLCP Data Preamble PLCP ACK X micro sec. PLCP PLCP 802.11g Only Pre Data ACK Pre OFDM > 2X micro sec. PLCP PLCP Preamble Pre Data ACK g Client PLCP CTS Pre 802.11g/b Virtual Carrier Sense Carrier Sense b Client

  34. Concurrent High Performance • Separate 802.11b and 802.11g networks into different BSSIDs • Logically isolate b and g clients • Creates packet level interoperation • Controlled channel access • g only window • b only window • Adaptively determine the window period • Protocol content • Flow-level info (upstream & downstream) • Number of b clients • Number of g clients

  35. Deployment Architecture DHCP Server AP AP AP RADIUS Server Meru Controller Virtual Wireless Subnet • Separate BSSIDs for b and g clients • AP’s can advertise each b and g network (2 BSSIDs) • APs control channel access based on required b and g resources • APs utilize adaptive control algorithms to determine window period Routed Core Meru AP to controller tunnels established over routed infrastructure 802.11b ESSID #1 b b 802.11g ESSID #2 g g g

  36. Meru Eliminates Trade-Off Between Backward Compatibility and g Throughput TCP 1g +1b g client perf. UDP g (with b clients present) TCP 1g ~10.1 ~22.6 ~15.8 ~10.3 ~14.8 ~3.4 Meru Meru Meru Vendor C Vendor C Vendor C Source: Meru Lab Tests

  37. Summary • Breakthrough Air Traffic Control Technology Delivers Concurrent 802.11b and 802.11g with High Performance • Simplify 802.11g deployment – no new APs • Highest 802.11g throughput in mixed b/g networks • Leverage deployed 802.11b clients • Eliminate user performance compromise

  38. Location Based Services

  39. Planning / Site Survey – “Snap Shot” • Create Network Plan: • Upload map (.jpg or .png file, no need for CAD drawings) • Draw walls and other obstacles (optional) • Place access points on the map • Simulate the network coverage • Perform Site Survey • Upload map (.jpg or .png file, no need for CAD drawings) • Deploy the APs as per plan Survey the site - Measure the coverage • Fix the coverage holes if any by adding APs or adjusting antennas

  40. RF Visualization – “Real-Time” Visualize Coverage • Visualize coverage based on signal strength, data rate, • Determine which areas support given ESSID, or channels • Visualize network performance and coverage holes

  41. Location Tracking Applications • Real-time location of Rogues, clients • Pinpoint rogue device (AP or client) to specific location (in a cubicle, in the hallway, outside the building) • Allow connectivity only when client at specific location (e.g. inside building) • Real-time capacity management/troubleshooting • Identify relevant portion of a network for capacity adjustment or troubleshooting based on caller’s location • Mobile asset tracking • Locate critical equipment or assets in hospital, manufacturing, retail environments • E-911 support • Meet regulatory requirements for calls that require emergency dispatch

  42. Location Tracking Technology • Traditional approaches: • Closest AP – find the AP that hears a signal the loudest • Very coarse granularity (point in 60’x60’ or 3600 sq ft area) • Triangulation – overlap coverage from 3 different APs • Granularity of ~ 30’ • Challenges: Reflection, attenuation, multi-path • RF-Fingerprinting – predict signal strength at every grid point, and match against it • Hours of RF signature training ( ‘can you hear me now?’ approach) • Granularity of ~10’

  43. Summary • Over-the Air QoS is required for Converged WLAN networks • Breakthrough Technology Delivers Concurrent 802.11b and 802.11g with High Performance • “Stay tuned” for Location based WLAN services

  44. Thank You Nate Walker Director, Product Management nwalker@merunetworks.com

More Related