Linee guida per il disegno di una rete

Wireless a elevate prestazioni

Formazione Online

Andrea Rossi – System Engineer

andrea.rossi@netgear.com

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Product Portfolio

Storage

Security Switching

Wireless

Business

Know Your Deployments

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Coverage Limited Capacity Limited

Considerations

+ How many Wireless Devices will want connectivity to the WLAN?

+ Where will these devices be and what area does it need to cover?

+ What applications would you like to use over the WLAN?

+ Would guest access or multiple groups be a requirement?

+ How is the current wired network constructed? 100mb? Gigabit? Fibre / Copper?

+ What levels of Security are needed?

+ What about future expansion? Other types of devices?

+ Would the system be used for VoIP calls?

+ Is there a requirement for external coverage?

What is considered High Density?

+ Large number of people in a small confined area

+ High demand of application access on Wireless

+ General Rule of Thumb:

•More than 20 active users in the proximity of coverage of single AP (500 – 1000 ft2)

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How much throughput your AP support?

300 Mbps * 2 = 600 Mbps (dual band 2x2 AP)

30 users

600 Mbps / 30 = 20 Mbps

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We support 20 Mbps per user !!

Common Sizing Mistake

Better Rule of Thumb Design of High Density

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For 25 Active Clients: Avg of 2 – 3 Mbps / client

Start Impact After

600 Mbps Packet and protocol overhead (-50%) 300 Mbps

300 Mbps Slow or ‘far-away’ clients (-50%)!! 1 Mbps client takes 100x more airtime to transmit 1 frame vs. a

100 Mbps client (.11a/b/g clients or clients at the edge of cell)

150 Mbps

150 Mbps Uneven distribution of 2.4/5 clients (-50%) 75 Mbps

75 Mbps Control traffic (-25%)Multicast, control, probe, etc. generally at 1 Mbps rate

50 Mbps

50 Mbps OthersInherent co-channel and adjacent channel interference, bad

behavior clients, network re-transmissions

What is the typical bandwidth needed per application?

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Video Throughput

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Typical rule of thumb: 1 to 3 Mbps

Parameters for Capacity Based Networks

+ # of users in a specific area covered by single AP

+ # of Wi-Fi devices per person

+ % of users that are expected to be active

+ Types of applications and throughputs needed

+ Mix of applications

+ Type of clients in the network (2.4 vs. 5 GHz)

+ Legacy vs. .11n clients

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Parameters for Coverage Based Networks

+ Floor plan

+ Types of constructions and obstructions• concrete, brick, drywalls, elevator shafts

+ Types of deployment• Offices, cubicle, warehouse, single room motels/hotels

+ Height of floor• 10 feet/3 meter (offices), 20 feet/6 meter (warehouse), 30 feet/9 meter (gym)

+ # of floors

+ Exclusion area

+ High density / Low density separations

+ Important coverage areas• CEO office, guests/publicity areas

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High Density Recommendation (1)(start with AirPlanner and Identify High Density areas)

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High Density Area

High Density Recommendation (2)(Dual Band Concurrent Access Points)

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YES

WNDAP360

WNDAP350

WNDAP660

NO

WNAP210

WN370

WNAP320

WNDAP620

Enable both 2.4 + 5 GHz Radios

High Density Recommendation (3)(Design overlap with 2-3 AP connectivity)

14HD Area with 3 AP Coverage

High Density Recommendation (4)Load Balancing to meet excess load

Set the max client for each radio at 25

Set the minimum RSSI threshold to connect at 40 (-73 dBm)

High Density Recommendation (5)turn down power, not up

+ Often mistake is turn up AP power, but that will cause co-channel and adjacent channel interference

+ Turning 2.4 GHz output power to ½ or ¼ and 5 GHz output power to ½ and add more AP is better solution

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High Density Recommendation (6)Upgrade wired network

L3 L2 AP

1G links1G or 10GMultiple 10 or

100 Mbps

High Density Design Recommendations

+ Start with AirMagnet planner and identify locations of High Density

+ Always spec’d AP with dual band concurrent radios• YES: WNDAP350/360/660

• AVOID: WNAP210/320/620/WN370

+ Always enable both radios

+ Design Wi-Fi where all clients can reach 2-3 AP’s

+ Load balancing to spread out traffic to less loaded AP’s

+ Upgrade wired network to support higher throughput AP’s

+ Explore to use bonded 40 MHz channels in 5 GHz where appropriate

+ Actual stress test prior to live deployment

Why Basic Survey?

+ Gain Visibility of site and gain clearer idea of requirement.

+ Understand the environment and how RF performs / check interference.

+ Understand the Network background, and provide opportunities to supply other technologies (Security/ Switching / POE / Storage).

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Types of Wireless Site Surveys

Three main types of surveys

Passive Active Predictive

Listen for

Signal strength

Noise Level

Not associated

Associate to AP

Round trip time

Throughput

Packet loss

Simulated

Modeling

RF attenuation

Wall construct

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&

Onsite evaluation

Plan your visit…

Tools 1st 30 minutes Timing

PC

Camera/phone

WiSpy

AirMagnet

InSSIDer

RF Spectrum

Floor map

Visual check

Requirement synch

Test locations

PoE !!

Single floor (hours)

Multi floors (days)

Multi bldgs (week)

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&

Conduct TestsActive Survey

AP Location

Associate to AP

Walk around Record

Key Parameters

Record boundaries

New Location

Passive Survey

Interferers, Other AP’s, Channels

Throughput (Mbps)

Round trip time (msec)

Packet loss

Signal strength (dBm)

Signal to noise (dBm)

Background noise (dBm)

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PROJECT ANALISYS

PROJECT DEFINITION

EXPANSION

Where NETGEAR can help

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Product Portfolio

Storage

Security Switching

Wireless

Business

WNAP210

WNAP320

WNDAP350

WNDAP360

WN370

a/b/g/n(2x)

Multi-BSSID

Controller

Managed

Performance

WNDAP620

WNDAP660

450 Mbps

3x3 802.11n

Advanced Security

Controller

Managed

Premium

WN203

WN604

WAC120

Simple installation

Basic security

Standalone

SOHO

Access Point Diversity

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Explore Controller

Compatibility

WND930

300 Mbps

2x2 802.11n

Advanced Security

Controller

Managed

Outdoor

Why a Wireless Controller?

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Helps speed up deployment:

• Easy User Interface -hiding sophisticated algorithms

• Integrated planning tools: Predicted coverage per building / floor

Helps stay connected:

• Seamless L2/L3 fast roaming

• Automatic load balancing and RF planning, incl. advanced QoS / Rate limiting

Helps enforce comprehensive

security:

• RADIUS, Active Directory authentication

• VLANs compliance, internal / external AAA server

• Captive portal and Guest access management

Wireless Controller Solution Scalability

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Up to 2500 devices Up to 6000 devices 15000+ devices

Wireless Controller / Management Solution

ProSAFE Wireless

Controller• Secure, enterprise class control

• Scale from 20 to 150 AP’s

• Stack 3 Controllers to support upwards of 3000 devices

• Full mobility / roaming support

• Guest Captive Portal

• Stack for redundancy / resiliency

• 10 AP incremental license

WC7520

Advanced, performance based wireless management

• Secure, enterprise class control

• Scale from 2 - 50 APs per

controller

• Stack 3 Controllers to support

upwards of 6000 devices

• Stack for redundancy / resiliency

• 802.11ac ready

• Premium 11n AP support

• 10 AP incremental license

ProSAFE WC7600

Product Detail

Advanced, performance and high density based wireless management

• Secure, enterprise class control

• Scale from 2 - 300 APs per

controller

• Stack 3 Controllers to support

upwards of 18000 devices

• Stack for redundancy / resiliency

• 802.11ac ready

• Premium 11n AP support

ProSAFE WC9500