1. 6/26/2015Wireless Networking J. Bernardini1 Wireless Networking WLAN Site Survey Module-07 Jerry Bernardini Community College of Rhode Island 6/26/20151Wireless Networking J. Bernardini

2. 6/26/2015Wireless Networking J. Bernardini2 Presentation Reference Material CWNA Certified Wireless Network Administration Official Study Guide, Fourth Edition, Tom Carpenter, Joel Barrett – Chapter 6 6/26/2015Wireless Networking J. Bernardini2

3. 6/26/2015Wireless Networking J. Bernardini3 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)

4. 6/26/2015Wireless Networking J. Bernardini4 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

5. 6/26/2015Wireless Networking J. Bernardini5 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

6. 6/26/2015Wireless Networking J. Bernardini6 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

7. 6/26/2015Wireless Networking J. Bernardini7 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

8. 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 6/26/2015Wireless Networking J. Bernardini8

9. Questions Answered by Physical Site Surveys 6/26/2015Wireless Networking J. Bernardini9

10. Questions Answered by RF Site Survey 6/26/2015Wireless Networking J. Bernardini10

11. Manual RF Site Survey Breakdown 6/26/2015Wireless Networking J. Bernardini11

12. 6/26/2015Wireless Networking J. Bernardini12 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

13. Overall Business Objectives Quality improvement (Better) Efficiency improvement ( Faster) Cost reduction (Cheaper) Increased production (More) Organizational continuity (Continue to exist) Sarbanes-Oxley (accountability) 6/26/2015Wireless Networking J. Bernardini13

14. Organization’s Needs and Objectives Determine business requirements User requirements-bandwidth related Functional requirements Budgetary Constraints Regulatory Constraints 6/26/2015Wireless Networking J. Bernardini14

15. 6/26/2015Wireless Networking J. Bernardini15 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

16. 6/26/2015Wireless Networking J. Bernardini16 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

17. 6/26/2015Wireless Networking J. Bernardini17 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

18. 6/26/2015Wireless Networking J. Bernardini18 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

19. 6/26/2015Wireless Networking J. Bernardini19 Site Survey Tools:Single-frequency analyzer

20. Spectrum Analyzer Measures RF energy 6/26/2015Wireless Networking J. Bernardini20 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

21. 6/26/2015Wireless Networking J. Bernardini216/26/201521Wireless Networking J. Bernardini Cheep Way to View RF and Stations in Area

22. WiFi Hopper 6/26/2015Wireless Networking J. Bernardini22 Website: http://wifihopper.com/overview.htmlhttp://wifihopper.com/overview.html

23. 6/26/2015Wireless Networking J. Bernardini23 Airmagnet Site Survey Tool 6/26/2015Wireless Networking J. Bernardini23

24. 6/26/2015Wireless Networking J. Bernardini24 AirMagnet Survey AirMagnet Survey This 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. 6/26/2015Wireless Networking J. Bernardini24

25. 6/26/2015Wireless Networking J. Bernardini25 Site Survey Tools: Measurement Tools (continued) Network Analyzers: Can be used to pick up packets being transmitted by other WLANs in area – Provide additional information on transmissions – Packet sniffers or protocol analyzers – Not used in placement of AP

26. 6/26/2015Wireless Networking J. Bernardini26 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

27. 6/26/2015Wireless Networking J. Bernardini27 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

28. 6/26/2015Wireless Networking J. Bernardini28 Sample site survey form

29. 6/26/2015Wireless Networking J. Bernardini29 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

30. 6/26/2015Wireless Networking J. Bernardini30 Performing a Site Survey: Gathering Data (continued)

31. 6/26/2015Wireless Networking J. Bernardini31 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

32. 6/26/2015Wireless Networking J. Bernardini32 Position of APs

33. 6/26/2015Wireless Networking J. Bernardini33 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

34. 6/26/2015Wireless Networking J. Bernardini34 Survey Coverage Pattern

35. 6/26/2015Wireless Networking J. Bernardini35 Survey Data rate boundaries

36. 6/26/2015Wireless Networking J. Bernardini36 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

37. 6/26/2015Wireless Networking J. Bernardini37 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

38. 6/26/2015Wireless Networking J. Bernardini38 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

39. 6/26/2015Wireless Networking J. Bernardini39 Table of measurements

40. 6/26/2015Wireless Networking J. Bernardini40 Data rate coverage map

41. 6/26/2015Wireless Networking J. Bernardini41 3-D signal-to-noise ratio plot is the output of some survey applications

42. 6/26/2015Wireless Networking J. Bernardini42 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