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Wireless Networking WLAN Site Survey Module-09. Jerry Bernardini Community College of Rhode Island . 6/7/2014. Wireless Networking J. Bernardini. 1. Presentation Reference Material. CWNA Certified Wireless Network Administration Official Study Guide

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wireless networking wlan site survey module 09

Wireless NetworkingWLAN Site SurveyModule-09

Jerry Bernardini

Community College of Rhode Island

6/7/2014

Wireless Networking J. Bernardini

Wireless Networking J. Bernardini

1

presentation reference material
Presentation Reference Material
  • CWNA Certified Wireless Network Administration Official Study Guide

(PWO-104), David Coleman, David Westcott, 2009, Chapter-15,16

  • CWNA Certified Wireless Network Administration Official Study Guide, Fourth Edition, Tom Carpenter, Joel Barrett –
    • Chapter 6, pages 232-318
  • The California Regional Consortium for Engineering Advances in Technological Education (CREATE) project

6/7/2014

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2

what is a site survey
What is a Site Survey?

Process of planning a WLAN to meet design goals

When installing a WLAN for an organization, areas of dead space might not be tolerated

Ensure blanket coverage, meet per-user bandwidth requirements, minimize “bleeding” of signal

Factors affecting wireless coverage goals:

Devices emitting RF signals

Building structure (walls, construction materials)

Open or closed office doors

Stationary versus mobile machinery/equipment

Movement of mobile walls (e.g., cubicles)

Wireless Networking J. Bernardini

what is a site survey1
What is a Site Survey?

Factors affecting wireless coverage goals (continued):

Expansion of physical plant or growth of organization

Existing WLANs

Both inside organization, and within nearby organizations

Site survey: Process of planning a WLAN to meet design goals

Effectiveness of a WLAN often linked to thoroughness of the site survey

Wireless Networking J. Bernardini

design goals for a site survey
Design goals for a site survey

Achieve best possible performance from WLAN

Certify that installation will operate as promised

Determine best location for APs

Develop networks optimized for variety of applications

Ensure coverage will fulfill organization’s requirements

Locate unauthorized APs

Wireless Networking J. Bernardini

more site survey goals
More Site Survey Goals

Map nearby wireless networks to determine existing radio interference

Reduce radio interference as much as possible

Make wireless network secure

Survey provides realistic understanding of infrastructure required for proposed wireless link

Assists in predicting network capability and throughput

Helps determine exact location of APs and power levels required

Wireless Networking J. Bernardini

when to perform a site survey
When to perform a site survey

Before installing a new wireless network

Before changing an existing wireless network

When there are significant changes in personnel

When there are changes in network needs

After making physical changes to a building

Wireless Networking J. Bernardini

project planning overview
Project Planning Overview
  • User’s Requirements

Budget Population

Applications Performance

Security Coverage Area

Physical & Logical Network Site Environment

site survey
Site Survey
  • A site survey is very important before you deploy a wireless network.
  • A site survey involves analyzing a site from an RF perspective.
    • Coverage
    • Interference Sources
    • Equipment Placement
    • Power Requirements
    • Wiring Requirements
preparing for a site survey
Preparing for a Site Survey
  • Preliminary Plan
    • Existing Network
    • Towers and Roofs
    • Coverage
    • Access Point Locations
    • Security
facility analysis
Facility Analysis
  • What type of Facility?
    • Personal
    • Small Office – Home Office, (SOHO)
    • Real-estate Office
    • Small Warehouse
    • Hospital
    • Manufacturing Plant
    • Corporate or Educational Campus
physical and rf site surveys
Physical and RF Site Surveys
  • Two major categories of site surveys
  • Physical Survey and RF Survey
  • Physical Survey
    • Examination of physical environment
  • RF Survey
    • Examination of RF activity

Wireless Networking J. Bernardini

questions answered by physical site surveys
Questions Answered by Physical Site Surveys

Wireless Networking J. Bernardini

questions answered by rf site survey
Questions Answered by RF Site Survey

Wireless Networking J. Bernardini

manual rf site survey breakdown
Manual RF Site Survey Breakdown

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obtaining business requirements
Obtaining Business Requirements

Determine business reasons why WLAN being proposed or extended

If this step skipped, almost impossible to properly design and implement the network

Primary data gathering method is interviewing

Must determine type of mobility required within organization

Must determine per-user bandwidth requirements

May be different “types” of users with different bandwidth requirements

Wireless Networking J. Bernardini

overall business objectives
Overall Business Objectives
  • Quality improvement (Better)
  • Efficiency improvement ( Faster)
  • Cost reduction (Cheaper)
  • Increased production (More)
  • Organizational continuity (Continue to exist)
  • Sarbanes-Oxley (accountability)

Wireless Networking J. Bernardini

organization s needs and objectives
Organization’s Needs and Objectives
  • Determine business requirements
  • User requirements-bandwidth related
  • Functional requirements
  • Budgetary Constraints
  • Regulatory Constraints

Wireless Networking J. Bernardini

site survey tools wireless tools
Site Survey Tools: Wireless Tools

Most basic tool is AP itself:

Position AP in various locations, monitor signal as you move

APs should have ability to adjust output power

APs should have external antenna connectors

Test effectiveness of different antenna types in different situations

May need DC-to-AC converter for testing

Notebook computer with wireless NIC also essential for testing

Previously configured and tested

Wireless Networking J. Bernardini

site survey tools measurement tools
Site Survey Tools: Measurement Tools

Site Survey Analyzers: Specifically designed for conducting WLAN site surveys

Software often built into AP

Receive Signal Strength Indicator (RSSI) value

Full-featured site survey analyzer software settings:

Destination MAC Address

Continuous Link Test

Number of Packets

Packet Size

Data Retries

Wireless Networking J. Bernardini

site survey tools measurement tools continued
Site Survey Tools: Measurement Tools (continued)

Site Survey Analyzers (continued):

Full-featured site survey analyzer software settings (continued):

Data Rate

Delay Between Packets

Packet Tx Type

Unicast or multicast

Percent Success Threshold

Basic survey analyzer software contains far fewer features

Wireless Networking J. Bernardini

spectrum analyzers
Spectrum Analyzers

Scan radio frequency spectrum and provides graphical display of results

Typically measure signal-to-noise ratio

Single-frequency analyzers measure signal-to-noise ratio at specified frequency

Helpful in identifying interference problems

Thus, helps properly position/orient AP

Costly $500 $50,000

Wireless Networking J. Bernardini

spectrum analyzer measures rf energy
Spectrum Analyzer Measures RF energy

Frequency range: 100kHz - 6 GHz.

Internal preamplifier with frequency range from 100 kHz - 6 GHz.

Displayed average noise level typ. -135 dBm (RBW 100 Hz).

0.5 dB typ. level accuracy up to 6 GHz.

Resolution bandwidths 100 Hz - 1 MHz, 1 and 3 steps.

Wide range of detectors; sample, max/min peak, auto peak, RMS.

Cost: $13,500

Wireless Networking J. Bernardini

wifi hopper
WiFi Hopper

Website: http://wifihopper.com/overview.html

Wireless Networking J. Bernardini

airmagnet site survey tool
Airmagnet Site Survey Tool

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25

airmagnet survey
AirMagnet Survey

AirMagnet SurveyThis WLAN planning solution stands apart from other market planning solutions by enabling enterprises to collect live signal, packet and spectrum data during their site surveys. This allows enterprises to simulate and measure network performance in the most scientific way possible—with the most accurate depiction of a real-world user experience-which ultimately results in a better performing network.

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26

site survey tools documentation tools
Site Survey Tools: Documentation Tools

Create a “hard copy” of site survey results

Make available for future reference

No industry-standard form for site survey documentation

Site survey report should include:

Purpose of report

Survey methods

RF coverage details (frequency and channel plan)

Throughput findings

Sources of interference

Wireless Networking J. Bernardini

site survey report material
Site Survey Report Material

Site survey report should include (continued):

Problem zones

Marked-up facility drawings with access point placement

Access point configuration

Use plain paper and building layout blueprints as tools

Advisable to create database to store site survey information and generate reports

Wireless Networking J. Bernardini

survey security and site documents
Survey Security and Site Documents

Defining Security Requirements: Consider type of data encryption and type of authentication that will take place across WLAN

Consider existing security policies and procedures

Gathering Site-Specific Documentation:

Blueprints, facility drawings, and other documents

Show specific building infrastructure components

Inspecting the site

Document changes to blueprints and get visual perspective

Behind-the-scenes site inspection

Documenting Existing Network Characteristics: New or expanded WLAN will “dovetail” into network already in place

Determine degree to which WLAN will interact with other wired networks

Legacy systems may require additional equipment to support WLAN

Wireless Networking J. Bernardini

performing a site survey performing the survey
Performing a Site Survey: Performing the Survey

Collecting RF Information:

Note objects in and layout of room

Use digital camera

Position AP

Initial location will depend on antenna type

Document starting position of AP

Using notebook computer with site survey analyzer software running, walk slowly away from AP

Observe data displayed by analyzer program

Data rate, signal strength, noise floor, and signal-to-noise ratio

Wireless Networking J. Bernardini

position of aps
Position of APs

Wireless Networking J. Bernardini

collecting rf information
Collecting RF Information

Continue moving until data collected for all areas

Data collected used to produce:

Coverage pattern: Area where signal can be received from the AP

Data rate boundaries: Range of coverage for a specific transmission speed

Throughput: Number of packets sent and received and data rates for each

Total transmission range: Farthest distance at which signal can be received by wireless device

Wireless Networking J. Bernardini

survey data rate boundaries
Survey Data rate boundaries

Wireless Networking J. Bernardini

rf data collection
RF Data Collection

Collecting Non-RF Information:

Sources of interference can include:

Wire mesh security windows, Aquariums, Outer walls, Ceramic or marble floors, Concrete floors or pillars, Security booth bullet-proof glass, Mirrors, and Elevator shafts or filing cabinets

Electrical and network connections

Outdoor Surveys: Similar to indoor surveys, but must consider climatic conditions, trees, different possibilities for antenna positions

Wireless Networking J. Bernardini

performing a site survey performing the survey1
Performing a Site Survey: Performing the Survey

Outdoor Surveys (continued):

Different tools may be required

GPS

Range finder

Tape measure

Lighting beacons, flares, and spotlights

Finalizing the Survey Documents: Final result is map of optimal areas of coverage for placement of access point

If results unacceptable, must relocate AP and start over

Wireless Networking J. Bernardini

creating the site survey report
Creating the Site Survey Report

Narrative section:

State customer requirements

Outline methodology

Outline all steps taken during survey

Clearly state results of measurements

May have tables of measurements

Recommendations

Should always address security

Graphic section:

Generally includes maps and diagrams of coverage area

Data rate coverage map

Signal-to-noise ratio plot

Wireless Networking J. Bernardini

table of measurements
Table of measurements

Wireless Networking J. Bernardini

data rate coverage map
Data rate coverage map

Wireless Networking J. Bernardini

3 d signal to noise ratio plot is the output of some survey applications
3-D signal-to-noise ratio plot is the output of some survey applications

Wireless Networking J. Bernardini

preparing for a site survey1
Preparing for a Site Survey
  • Facilities Analysis (Floor Plan, Maps, Satellite Imagery)

Satellite or Ariel Imagery

Floor Plan – Network

WLAN

Naming Convention

Santa Maria,SM

BLDG-A

BLDG-B

Maps of Campus/Facilities

wlan-sm-bldga-rm12ap3

RM-12-AP3

RM-12-AP4

RM-10-AP2

existing networks
Existing Networks
  • Is there already a network in place?
    • Wired
    • Wireless
    • Wired-Wireless
    • Topology – Location of existing equipment
    • Current User’s Requirements
area usage and towers
Area Usage and Towers
  • Indoors, outdoors, or both.
    • Indoor
      • Building Type Floor Plan
      • HVAC Security
    • Outdoor
      • Weather Security
      • Towers Power
      • Environmental Obstructions (RF)
purpose business requirement
Purpose & Business Requirement
  • Purpose, Needs, and Expectations
    • Define Business Model
    • User needs
    • Interview with client and users
    • Wireless impact on business operation
bandwidth roaming
Bandwidth & Roaming
  • Bandwidth and Throughput
    • 802.11 a, b, g, n and Bluetooth
    • Number of Users
    • Types of Applications
    • Environmental changes as a function of seasons.
    • Mobility or Roaming needs
available resources
Available Resources
  • Project Budget
  • Time Line
  • Trained Personnel
  • Floor Plans, CAD
  • Existing Site Survey Reports
  • Access to Equipment and Site Areas
security requirements
Security Requirements
  • Network Security – Wired and Wireless
    • Corporate Mandated Security
    • Current Security Policies
    • Hierarchy of Data Security
    • Training of Users
site survey equipment
Site Survey Equipment
  • Access Point, PC Card, and USB Adaptor
  • Antennas, Cables, and Connectors
  • Desktops, Laptops, and PDA’s
  • Power Supplies and Batteries
  • Ladder, Measure, and Hand Tools
  • Analysis Software
  • GPS, Cell Phone, Walkie-Talkie
  • Forms, Floor Plans, and Paper
site survey software
Site Survey Software

Netstumbler - www.netstumbler.comThis program is great for seeing what other access points are nearby. This can help you by seeing what other SSID\'s are around so you know what NOT to name yours, as well as help you pick a channel that doesn\'t have a lot of people using it, giving you a better signal between your access point and your client. Works only with certain cards. Windows and PocketPC versions are available.

Kismet - www.kismetwireless.netThis program is similar to Netstumbler, though for the open source world. Additional features that Kismet has include the ability to log any traffic heard, as well as providing additional detailed information. Unlike Netstumbler, Kismet is COMPLETELY passive, meaning no transmitting is done to obtain any of the information shown. Great for finding rogue access points as well as their users in a corporate environment. *nix, Familiar (Linux on iPAQ) and Sharp Zaurus versions are available.

site survey software1
Site Survey Software

Airsnort - airsnort.shmoo.comThis program was used in the early days of 802.11b to determine whether or not your access point and/or wireless adapters used insecure initialization values for the RC4 encryption used by WEP. Many newer AP\'s and cards have resolved this by not using the 3000-something weak IV\'s that could lead to the WEP key being cracked. *nix/X-Windows version available. Also WPA and WPA2 are now in use.

access point
Access Point

Electrical Specifications

Using the Power Adapter

Voltage (Input) = 100 to 240 VAC (50-60 Hz) @ 0.4 A

Voltage (Output) = 12 VDC

Power Consumption = 10 Watts

Using Active Ethernet

Input Voltage = 42 to 60 VDC

Output Current = 200mA at 48V

Power Consumption = 10 Watts

Recommend: 12 volts DC at 1.5 Ampere Power Source

48 volts DC at 250 mA Power Source

Variable RF power output would be a nice feature. If not available consider fix or stepped attenuators.

access point remote power
Access Point Remote Power

12 volt, 7-amp/hr recharge in less than 12 hours.

12 volt, 17-amp/hr recharge in less than 12 hours.

spectrum analyzer

5.0

Frequency, f (GHz)

2.0

Spectrum Analyzer

Two basic types:

Hardware and Software

network protocol analyzer
Network & Protocol Analyzer

Wireshark

Fluke

AirMagnet

site survey kit checklist
Site Survey Kit Checklist
  • See Site Survey Kit Checklist in the text.
  • Laptop or PDA
  • Wireless PC card and AP as needed.
  • Power Pack
  • Site Survey Software
  • Location maps and building diagrams
  • Cables & Connectors
  • Proper Clothing
site survey kit checklist1
Site Survey Kit Checklist
  • Hand Tools and mounting hardware
  • Digital Camera
  • GPS, Terrestrial Telescope, Binoculars
  • Measuring wheel, tape measure, and level
  • Appropriate transporting equipment
  • Documentation and writing materials
  • Antennas
  • Anything else you meant to bring.
conducting a site survey
Conducting a Site Survey
  • Examine the network usage problems the wireless LAN solves.
  • Study blueprints of the proposed wireless LAN site.
  • Conduct a physical walk-through and inventory.
  • Measure the radio frequency (RF) transmissions.
  • Indoor and/or Outdoor Survey.
indoor survey
Indoor Survey
  • AC Power Outlets and Grounds
  • Wired Network Connectivity
  • Potential RF Obstructions (Metal)
  • Potential Interference Sources
  • Access to all areas
floor plan
Floor Plan

65 feet

42

feet

indoor survey1
Indoor Survey

65 feet

2

3

42

feet

Utilities

and POP

Ethernet

RF Field

1

Gateway

Access Points

outdoor survey
Outdoor Survey
  • Trees, buildings, lakes, mountains, or other obstructions between linked sites.
  • Consider growth and foliage of trees, bushes, and plants.
  • Line of Sight and distance between stations.
  • Weather common to location.
  • Towers and roofs.
rf information gathering
RF Information Gathering
  • Range and Coverage Patterns
  • Data Rate Boundaries
  • Documentation
  • Throughput Test and Capacity
  • Interference Sources
  • Wired Data Connectivity
  • AC/DC Power Requirements
  • Outdoor Antennas
range and coverage patterns
Range and Coverage Patterns

Think Three Dimensional!

AP

range and coverage patterns1
Range and Coverage Patterns

AP

-47 dB

1

-61 dB

AP

AP

2

-61 dB

New Coverage Area

- 61 dB

range and coverage patterns2
Range and Coverage Patterns

Dead Spot

1

Dead Spot

2

3

Dead Spot

AP

N

Coverage Map

A dead spot is an area or zone where wireless network services are not

available because the signal between the client and the AP is blocked or

attenuated, usually by terrain, excessive foliage, buildings, or architectural features.

range and coverage patterns3

11

6

11

6

1

1

1

6

11

11

1

6

Range and Coverage Patterns

11

6

11

6

1

802.11b/g

6

11

36

44

40

40

802.11a

44

48

36

48

40

44

data rate boundaries
Data Rate Boundaries

AP

5.5 Mbps

2 Mbps

AP

throughput test capacity
Throughput Test & Capacity
  • Live testing of the network with actual data transfers.
  • Traffic congestion, bottlenecks, and future expansion.
  • Document baseline measurements for deliverables, (User Requirements) and maintenance and troubleshooting.
interference sources
Interference Sources
  • Active Interference – 2.4 GHz cordless phones, Medical Equipment, Microwave Ovens/sources, Bluetooth, X10 Devices, Other 802.11 Devices…
  • Passive Interference – Path Loss, Metal Walls, Concrete, Brick, Stucco, Foliage, Glass, People, Vehicles…
  • Signal Reflections - Multipath
ac dc power requirements
AC/DC Power Requirements
  • Is AC circuit available and at what rating?
  • Is a ground available?
  • Power over Ethernet?
  • Wired Network Connectivity
  • Backup Power
outdoor antennas
Outdoor Antennas
  • Temporary Antennas for a Site Survey.
site survey report format
Site Survey Report Format
  • Title Page
  • Abstract
  • User’s Requirements
  • RF Coverage Area
  • Throughput
  • Interference Sources
  • Problem Areas
  • Drawings
site survey report format1
Site Survey Report Format
  • Installation/Configuration Information
  • Cost Analysis
  • Conclusion
  • Appendices
summary
Summary

A site survey is an in-depth examination and analysis of a proposed wireless LAN site to meet design goals

Three categories of tools used

Wireless tools include the access point and notebook computers with a wireless NIC

Measurement tools include site survey analyzers, spectrum analyzers, and network analyzers

Documentation tools create a “hard copy” of the site survey results for future reference

Wireless Networking J. Bernardini

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