pervasive wireless lans
DESCRIPTION
Pervasive Wireless LANs. Serving The Needs Of Higher Education Kamal Anand VP Marketing [email protected]. Company Background. Founded in 2002 Customers include Higher Ed, Healthcare, Retail, Manufacturing, F500 Deployed in over 30 Higher Education Institutions. - PowerPoint PPT PresentationTRANSCRIPT
Pervasive Wireless LANs
Serving The Needs Of
Higher Education
Kamal Anand VP Marketing
2
Company Background
Founded in 2002
Customers include Higher Ed, Healthcare, Retail, Manufacturing, F500
Deployed in over 30 Higher Education Institutions
3
Wireless LAN Evolution Hubs, Switching to Coordination
Number of Clients and Coverage
Applications
Products /Technology
• Email, Web
Stand Alone Hot-Spot
• Email, Web• Voice and Data• Business applications• Primary connectivity• Video emerging
Pervasive
Architecture
• Bridge
• Wireless hub
• Centralized security and management
• Minimal AP • WLAN Switch
• High Density, QoS, • Transparent mobility• Multi-Services WLAN
• Coordinated WLAN*
* Gartner’s Dulaney describes as “4th Generation
4
Enterprise WLAN Product Evolution
Generation 1 + Central ManagementSecurity
2000-021st GenerationStand-alone
2003-42nd GenerationCentralized
2004-53rd GenerationCoordinated
Aggregated AP’sCentral Switch/
ApplianceStand-alone
Cisco 1200+SWANSymbol
Aruba, Trapeze, Airespace …
Meru
Generation 2 + RF IntelligenceHigh DensityQoSZero Handoff
Cisco 350Orinocco
RoamAbout
Basic Connectivity
Ser
vice
s /
Sca
le
Coordinated AP’sCentral Controller
5
Meru WLAN ProductsSimple Deployment Architecture
Floor 2Floor 2
Floor 1Floor 1
Data CenterData Center
L2 / L3Backbone
Virtual AP Virtual AP
AP
AP
Meru Controller
Meru AP
Coordinated Access Point► Air Monitor + Access Point ► Application Flow Classification► Contention management
Controller► Centralized appliance for
coordination, management and security
► Built-in application Flow-Detectors e.g. SIP, H.323, Spectralink SVP
► Platform for services: e.g. Location Tracking
6
Enterprise Scale Deployment
Floor 2Floor 2
Floor 1Floor 1
Data CenterData Center
Meru AP
AP
Remote Office
Central Campus
Servers - Radius, DHCP, LDAP Web
Branch Office
Internet
Deployment Options: L2 LAN between AP and controller
(e.g. branch office, corp bldg) L3 campus network between AP
and controller (e.g. campus) L3 WAN between AP and controller
(e.g. remote office)
Overlay Network Leveraging: Existing L2/L3 devices Existing WAN connections Existing WiFi clients
Meru Controller
7
Pervasive WLAN Requirements
Deployment and RF Intelligence
Predictable Performance in High Density
Multiple Applications: Data, Voice, and Video
Seamless Mobility
Integrated Security
► Budget constraints and service level expectations
► Lecture halls, classrooms, libraries, unions.
► Data today► Voice emerging – soft phones,
Wi-Fi phones► Video – lecture content, video
presentations
► Students, faculty, visitors – constant movement
► Student / faculty / guest security ► Integration with network access
control
Higher-Ed is Key Example
8
Wireless Channel Planning Problem
Access Points are hubs: RF is shared medium Connectivity bound by physical proximity to AP
► Signal strength degrades with distance► Trade-off between data rate and coverage
Spectrum is limited (particularly in 2.4GHz band): Capacity is bounded in space
Interference is dictated by neighborhood of both transmitter and receiver (i.e. transmit power control is necessary but not sufficient)
Goal is to deploy APs in a way that minimizes contention for shared spectrum across APs
How should you place Access Points in order to achieve pervasive coverage and optimum performance?
9
RF Design and Planning Myth
By doing channel planning and deploying on the three non-overlapping
channels you can avoid co-channel interference
10
Deployment of APs in Pervasive WLAN: Co-Channel InterferenceSignal
Strength
Distance
-68dBm
-95dBm
54Mbps
1Mbps
There are 3 non-overlapping channels in 2.4GHz(Ch 1, 6, 11)
x x
x
xx
x
11
Meru Coordinated WLAN Architecture
APs act as a coordinated system of antennas rather than each AP acting as an individual wireless hub
► All APs on the same channel have the same BSSID (wireless MAC address)► Client only sees only one AP on a channel
Physical WLAN Infrastructure
Client’s View of Meru WLAN
Benefits: Minimum RF Planning Handoff totally transparent to clients Load balancing transparent to clients Ok to over-deploy APs for redundancy
and rogue detection
12
Meru Simplifies DeploymentMeru’s RF Planning Framework
Automatic channel planning
Automatic power control
Coordination of channel access across APs
Virtualization of a “cell”
Global optimization of settings based on environment goals
13
MAC problem: Trade-off between Throughput and Density
20-25
Tot
al B
andw
idth
at
Pea
k (M
bps) 5
8
11
1
3
Baseband + Protocol Overhead
ContentionLoss
ContentionLoss
802.11 MACPerformance
Number of Simultaneous Contenders
Peak Aggregate Throughput in Single Cell Environment
CSMA throughput degrades with contention
Contention loss is more severe in 802.11 than Ethernet
Cannot detect collisions directly
Backoff scheme trades off fairness for scale
14
Meru Air Traffic Control TechnologyPredictable Performance with Density
20-25
Tot
al B
andw
idth
at
Pea
k (M
bps) 5
8
11
1
3
ContentionLoss
ContentionLoss
Today’s APPerformance
Meru AP Performance
Active Users Per AP
Today Meru
20-25
100+
Number of Active Users
Peak Aggregate Throughput
15
Predictable and Better End User Experience
Predictable, uniformly fair throughput across all clients
Throughput 1 AP + 20 Clients Throughput 1 Meru AP + 20 Clients
16
QoS RequirementsWired and Wireless LANs In order to provide Quality of Service,
the infrastructure must have the following components:
► Low delay► Low jitter► Low packet loss
Wired LANs addressed this by utilizing switches instead of shared medium hubs as well as increasing bandwidth
17
QoS: Wireless Requires More
S
R
Wired Network
SchedulingPackets MeetsRequirements
S
R
Needed:
Scheduling+
Contention Management
I
I
I
Wireless Network
► Packet scheduling provides QoS as duplex, switched medium
► Even with the old hub architecture collisions could be detected in real-time unlike wireless.
► Multiple stations contend for the same shared medium
► While transmitting, sender cannot listen at same time for collisions
► Scheduling not enough for QoS► Predictable channel access is key for
jitter and QoS – typical 802.11implementations don’t provide this
Sender
Receiver
18
Meru Air Traffic Control
Application Flow Detection
Application Flow Detection
Global RF Resource Knowledge
Global RF Resource Knowledge
Admission ControlAdmission Control
Control Mechanismsin 802.11 Standard
Control Mechanismsin 802.11 Standard
Meru QoSAlgorithms
+
Global knowledge of interference and resource usage at AP’s including knowledge of clients
Time-based accounting, not bandwidth-based Inter-cell Coordination
Deep packet inspection for understanding resource requirements of Application (e.g. SIP/Codec)
Resource management
+
+
Virtual carrier sense for uplink reservation/QoS Contention-free periods and contention periods.
Per-flow SchedulingPer-flow Scheduling Uplink and Downlink accounting of packets /
expected packets Reservation-based QoS
+
19
Generic Access Point + Standard Client
Access Point with Over-The-Air QoS
Standard Client
Meru Air Traffic ControlOver-The-Air QoS
Converged Network - voiceand data on same channels
Typically data and voice on Separate channels/network
20+
Low
APWired QoS
Wired QoS
Standards-basedOver-the-air
QoS AP
Voice
Quality
MOS Score
4.0+
Over-the-air QoS
20
How Meru Over-the-Air QoS Compares to Others
Meru Other Approaches
Global RF Knowledge and Inter-cell Coordination
Yes --
Application Flow Detection and Classification
Yes (Dynamic)Static ESSID-based or
Filters
Admission Control Yes --
Downlink (AP to Client)Reservation-based
True over-the air QoSSimple Priority of
packets
Uplink (Client to AP) Reservation-based True over-the air QoS
--
Fairness across clientsPer-class, Per-station,
time-based fairnessFIFO or packet based
21
Meru Air Traffic Control Technology Zero Handoff
Meru WLAN
Virtual AP Architecture
No Handoff For Client
BSSID = M BSSID = M
00:00
100ms – 1 sec between handoff
Today’s WLAN
BSSID = A BSSID = B
01:00
22
We needed a WLAN system that was easy to deploy across many buildings on campus, could be centrally managed over an IP routed network, and could implement different security policies for different classes of users. Meru’s plug-‘n-play deployment model with centralized policies and control, its ability to deploy access points anywhere on campus across IP subnets, as well as its flexibility in supporting 64 different ESSIDs each with a different security policy made the system move to the top of our evaluation list.
Mr. Richard W. Reeder, Chief Information Officer of SUNY Stony Brook University
”
“ SUNY Stony BrookMeru Customer Success Story
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Contention Management Effortless Scalability and Deployment
Supported over 500 users at the Conference on Instructional Technologies
With L3 mobility, extending wireless to a new site is as easy as plugging an AP into any data jack on the campus
Supports any user with a standard 802.11device without any client software
L2/L3 Network
Virtual AP
Student Center
LibraryComputer LabDormitories
Meru Controller
24
Key Benefits of Meru for Pervasive WLANs
1. Minimal RF Planning: Meru virtually eliminates RF planning and manages co-channel interference
2. Highly Scalable: Meru supports extremely high user densities with any dynamic mix of voice and data
3. Handoff: Meru provides for client handoff without any loss for higher quality voice and data applications
4. Convergence: Meru allows you to deploy WLANs with voice and data on the same Access Points, in multi-cell networks.
5. True b/g Performance: Meru gives g clients full rate performance in mixed b/g networks
