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									Montana State Campus Wireless
          Network


          Collin Daniel, ITC
         Ryan Scheppele, ECE
         Richard Wolff, ECE
         Mingliu Zhang, ECE
          September 22, 2003




                               9/22/03
Talk Outline


•   The big picture: goals and plans
•   MSU building characteristics
•   Wireless network economics
•   Deployment status and operations


Work partially funded by the Gilhousen Telecommunications
Program


                                                      9/22/03
MSU Campus Wireless Network
Committee
Chartered by ITAC, Spring 2003
•Jacob Becker, ASMSU
•Sheila Chaney, ResNet Coordinator
•Bob Friedrich, BTC
•Eric Hyyppa, KUSM
•Virginia Key, Internal Auditor
•Laura Krnavek, ASMSU
•Gary Orser, CCB
•Tom Morrison, Network Systems, ITC
•Pat Simmons, Finance, Communication Wiring and Telephone Services, ITC
•John Strothers, DBAA/Web System Administrator, ITC
•Ernie Visser, COE, CBE
•Richard S. Wolff, ECE (chair)



                                                                    9/22/03
Committee Charter
• Develop a wireless network vision for the entire campus
• Identify strategic objectives
• Develop and suggest policy and process
• Develop a plan to implement and ensure on-going
  operations, which would include but not be limited to
   – All operating costs,
   – A sustainable revenue stream
   – Long-range replacement funding
• Identify and address potential technical issues



                                                            9/22/03
Benchmarking
• Wireless networks on dozens of campuses
• Conducted surveys of web sites, discussions with
  campus IT managers, ResNet managers
                             Typical survey findings
  Issue                                  Response
  Purpose                                Augment wired network
  Authentication                         Yes: User ID and Password
  Security                               Encryption available but optional
  Wireless network use fee               No (part of regular computing services
                                         cost)
  Centralized management (ITC-like)      Yes

  Policy in effect                       Yes, and usually the same language



                                                                                  9/22/03
Objectives: What will a campus
wireless network do for us?
• Augment but not replace the wired network
• Enable mobility and portability
• Enable innovative classroom applications
  Reduce equipment costs by lowering the
  demand for computer labs
• Provide convenient services for guests
• Project a leading edge image for MSU


                                         9/22/03
Campus wireless network
architecture
                               Access point    To existing ITC network
                               management      Operations system
                               system (new)

                                                            To existing
                                                            authentication
                                                            servers
                                  Existing
                                  Ethernet
                                  switches
                                                            Redundant
                                                            Wireless         Existing campus
                                                             gateway               wired
                                                              (new)              network

                                  Existing
                                  Ethernet    Existing
                                  switches    Fiber optic
                                              links

                   Dedicated
                     new
                    wiring
   Wireless
   Access Points
   (new)


                                                                                   9/22/03
Technology choices

• Wireless system –
  – several WiFi standards to choose from: 802.11a, b, g
• Recommendation: converge on 802.11b
  –   Most mature
  –   Available built into new laptop computers
  –   Low cost
  –   Lots of competing, interoperable products
  –   Good coverage range



                                                           9/22/03
 Where are we now?
•Developing an implementation process
   •Measure environment
•Examined the life-cycle costs
•Set up a few demonstration projects
   • Renne Library – in place
   •EPS 108 – in place
   •Classroom application – 215 Cheever – in place
   •BTC – in progress

Moving toward a scalable rollout:coordinated by
           ITC, customer driven

                                                     9/22/03
Talk Outline


•   The big picture: goals and plans
•   MSU building characteristics
•   Wireless network economics
•   Deployment status and operations




                                       9/22/03
Overview

•   WLAN site surveys
•   Analysis of MSU buildings
•   Interference Issues
•   Current state of 802.11b activity at MSU




                                               9/22/03
  Purpose of a WLAN Site Survey

The purpose of a site survey is to determine
  the nature of WLAN signal propagation in
  a particular environment. Characteristics
  that must be identified include:
• Access point (AP) range
• Floor-floor penetration
• Potential hazards (shielding, noise, etc.)


                                           9/22/03
Conducting a WLAN Site Survey


 Simple site survey procedure:
   • Setup of wireless AP
   • Antenna selection/positioning
   • Measuring signal strength
   • Determination of coverage area



                                      9/22/03
WLAN Site Surveys in Roberts,
Cobleigh and EPS

For the survey of the engineering buildings, a
  Cisco Aironet 1200 AP was used in
  conjunction with a Compaq iPAQ PDA
  running the AirMagnet wireless network
  analyzer. In addition, a variety of antennas
  were used to determine the effectiveness of
  a higher-power antenna.


                                            9/22/03
Site Survey Tools used in MSU Surveys


   • Cisco Aironet 1200 Wireless Access Point
   • Antennas
     – 2.2 dBi “whip” antenna
     – 5.2 dBi omnidirectional antenna
     – 6.0 dBi sector antenna
   • Compaq iPAQ
   • AirMagnet Wireless Analyzer Software


                                            9/22/03
Test Cart and Antenna Mast




                             9/22/03
Close-up of AP and standard
antenna




                              9/22/03
2.2 dBi “whip” antenna




                         9/22/03
Close-up of high-power antennas




                                  9/22/03
5.2 dBi Omni-directional antenna




                                   9/22/03
6.0 dBi sector antenna




                         9/22/03
AirMagnet WLAN Analyzer




                          9/22/03
Cobleigh Hall Wireless Site Survey

  • 5th and 6th floors were mapped using a grid-
    system
  • AP was tested in four different points, using all
    three antennas at each point
  • Signal strength was measured on 5th and 6th
    floors
  • Data was imported into Matlab; contour plots
    were generated to indicate coverage area
  • Results: average


                                                        9/22/03
Renne Library Site Survey


• Like the Cobleigh Hall site survey, Renne
  Library was mapped using a grid system
• Active AP on 2nd floor was used for
  measurements; cart not needed
• 1st, 2nd and 3rd floors were measured
• Results: better than average



                                              9/22/03
E.P.S. Wireless Site Survey


• Access point was setup in three different
  locations (BTC, Atrium and EPS 108)
• Instead of mapping EPS, arbitrary points
  were chosen
• Signal levels were recorded on floorplan
• Results: much better than average



                                              9/22/03
Roberts Hall Wireless Site Survey


  • Access point was setup on 2nd and 3rd
    floors
  • Again, arbitrary measurement points were
    chosen and signal strengths were recorded
    on floor plan
  • Results: below average



                                                9/22/03
Wireless LAN Interference Issues


• Direct sequence spread spectrum (DSSS)
  vs. frequency hopping spread spectrum
  (FHSS) techniques
• Internal vs. external interference




                                           9/22/03
DSSS vs. FHSS


Frequency hopping spread spectrum
  transmissions use a small portion of the
  spectrum for a set time, then ‘hop’ to
  another frequency.
Direct sequence spread spectrum
  transmissions use a given frequency span
  simultaneously.


                                             9/22/03
DSSS vs. FHSS




                9/22/03
DSSS vs. FHSS




                9/22/03
Internal vs. External Interference


Internal interference is caused by wireless
  nodes within a WLAN that interfere with
  each other.

External interference is caused by any device
 not part of the WLAN infrastructure that
 disrupts the operation of the network.


                                              9/22/03
WLAN Activity at Montana State

 With the deployment of a campus-wide
  wireless network on the horizon, existing
  activity in the 2.4 GHz frequency band
  must be identified. To do this, the
  AirMagnet handheld was used to go “war
  walking” around the MSU campus.

 Active APs: roughly 20 on campus


                                              9/22/03
Summary


•   WLAN Site Surveys
•   Results of surveys at MSU
•   Interference
•   Current WLAN activity at MSU




                                   9/22/03
Talk Outline


•   The big picture: goals and plans
•   MSU building characteristics
•   Wireless network economics
•   Deployment status and operations




                                       9/22/03
 Models for network
 economics study

• Baseline case
• Baseline case with phased deployment plan
• Baseline case with high gain directional
  antenna applied
• Baseline case with both directional antennas
  and phased deployment plan applied



                                             9/22/03
Baseline case
Assumptions:
• 10-year study period
• Whole campus coverage will be provided in one year
• Space covered(about 0.18 sq miles): Mainly
  buildings, not including the free space
• Share the existed wired internet infrastructure
• Access Point (AP) with internal 2.2dBi gain dipole
  antenna applied (typical coverage range of 20
  meters)


                                                9/22/03
Baseline Case

Conclusion:
• The whole campus network is coverage-limited
  over the entire study period.
• Average traffic demand per unit area never exceeds
  the capacity of an AP
• All capital investment happens in the 1st year
• Only operating expense needed in the following
  year.


                                                  9/22/03
 Baseline case with phased
 deployment plan
Added Assumptions:
• 1st year: Library,Sub, Engineering building
• 2nd year:Remaining classroom buildings and research
  labs
• 3rd year: Others, residential and administration
  buildings,etc.
Advantage and disadvantage: Capital investment
 happens in 3 years, but the whole coverage can’t be
 provided in 1 year


                                                   9/22/03
Baseline case with high gain
directional antenna applied
Added assumptions:
• External higher gain 5.2dBi directional antenna
  ($250 each) applied to each AP
• Maximum transmission range of AP improves by
  a factor of 1/3 (measurements in Cobleigh
  Hall:20meters to 29 meters)
Advantages : Lower number of APs needed to
 cover the whole campus; Lower operation cost



                                                9/22/03
Baseline case with both directional
antenna and phased deployment plan applied

 Assumptions added :
 • Higher gain directional antenna applied
 • Phased deployment plan
 Conclusions:Least amount capital investment,
   spreading gradually in several years.The most cost-
   effective and favorable approach among these four
   cases. The financial results given will be based on
   this case.


                                                     9/22/03
Campus wireless network
architecture
                               Access point    To existing ITC network
                               management      Operations system
                               system (new)

                                                            To existing
                                                            authentication
                                                            servers
                                  Existing
                                  Ethernet
                                  switches
                                                            Redundant
                                                            Wireless         Existing campus
                                                             gateway               wired
                                                              (new)              network

                                  Existing
                                  Ethernet    Existing
                                  switches    Fiber optic
                                              links

                   Dedicated
                     new
                    wiring
   Wireless
   Access Points
   (new)


                                                                                   9/22/03
Network cost and expense

 Customer Premise Equipment (CPE) cost
 • Data service
     – WiFi network adapter ($50~$150)
     – Laptop with built in wireless network
        adapters($0)
 In our analyses, assume CPE costs are borne by
    users



                                                  9/22/03
Network cost and expense

 Access Point(AP) Unit includes:
 •   Cisco 1200 Aironet series access point ($650)
 •   Directional antenna($250)
 •   Power injector($46)
 •   Wiring plus the activating and amortizing of the
     existing Ethernet switches, space, and etc.($500)
 Total average cost: $ 1495/AP



                                                     9/22/03
 Network cost and expense

• Gateway ($11,175/each), 2 units needed
• Access Points Management System($6,100), 1 unit
• Misc. cost: $100,000 for 3-year investment (e.g.,
  engineering design, consultation,site preparation,
  installation,etc.)
• Operating expense:10% of the equipment costs each
  year



                                                 9/22/03
Network capital cost for each year
                                  Capital Cost($K)
System Equipment
                      1st year       2nd year          3rd year

                    1.495/AP*36   1.495/AP*48        1.495/AP*130
Access Point
                       =53.82        =71.76             =194.35

Gateway               11.175           0.0              11.175

AP Manage. System      6.10            0.0               0.0

Misc.                  16.67          22.22             61.11

Total                  87.76          93.98             266.64


                                                                  9/22/03
Network operation cost for each year

                               Operation Cost ($K)
System Equipment    1st year        2nd year         3rd year


Access Point         5.18            12.10            30.82


Gateway               1.0             1.0              2.0


AP Manage. System    1.08             1.08            1.08


Total                7.26            14.18            33.9



                                                                9/22/03
 Present worth of expenditures
(PWE) and cost/potential user/year

                                Capital and Operation Cost
Items
                     1st year      2nd year       3rd year   4th year


Total ($K)           95.02         108.16         300.54      33.9


PWE($K)              94.36          97.16         245.83      23.16


Cost/user/year ($)     6.4            6.6          16.67      1.57




                                                                     9/22/03
  Cost and expense summary

• PWE value is based on a 10% annual discount rate.
• After the 3rd year:
   – No capital investment needed.
   – The operating expenses are the same as the 4th year.
• Cost per user per year is based on the total potential
  user number of about 14750 (including students,
  faculty and staff)




                                                      9/22/03
Talk Outline


•   The big picture: goals and plans
•   MSU building characteristics
•   Wireless network economics
•   Deployment status and operations




                                       9/22/03
•Locations of Access Points
  •Cheever Hall
  •Renne Library
  •Burns/EPS


•Security
•Authentication
•Active Directory
•Blue Socket


                        Colin Daniel
                    ITC Network Analyst
                                   9/22/03
Renne Library AP use
http://www.lib.montana.edu/services/wireless/




                                        9/22/03

								
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