Roaming VoIP

1
Roaming VoIP?

• Steps toward Roaming VoIP and Some Opportunities
  That Still Exist

2
The Many Parts

• Moving Between Hotspots
• Dartmouth
• 802.11f
• 802.11k
• Providing Wireless Last Mile Access
• 802.16a
• 802.16e
• 802.20
• Providing Wireless Access to A Community
• WRAN 802.22
• Moving Between Differing Networks
• 802.11 Cellphone Combo Products

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Dartmouth (Center for Mobile Computing)

• Approx 1 sq mi
• 120 buildings
• A mix of contemporary and legacy systems
• As of 2000 4,200 undergrads, 1,500 grads, 3,115
  staff, 2,250 faculty
• Winner of the 2004 Educause Excellence in
  Networking Award
• EDUCAUSE is a nonprofit association whose
  mission is to advance higher education by
  promoting the intelligent use of information
  technology-www.educause.edu

4
Peter Kiewit Computing Services

• Academic Computing
• Administrative Computing
• Computing Support
• Technical Services

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Goals

• Untethered Campus Wide Internet Access
• Smart Classrooms
• Researchers collect/analyze data remotely
• Students monitor class/lab projects
  remotelybiological/chemical computer systems,
  various instruments
• In classroom or remote whiteboard collaberation
• Cost effectively combine voice, video data

6
Planning the Network

• Cisco, Dell, Apple and Alumni Working in the
  Computing Field
• Researched thoroughly beginning, in progress and
  throughout the Project
• Addressed resistance and concerns with training
  and integrating solutions into the plan

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The Access Points

• 476 Cisco Aironet APs
• Some powered by injector
• 100 coverage of
• 161 buildings, Major outdoor areas, Off-campus
  facilities, (Stadium, Boathouse, Etc.)
• Omni directional ant, micro-cell pattern
• Signal reuse lessen range-related problems
• Connected to wired backbone
• Delivers 11Mbps

10
AP Placement An Art More Than A Science

• Wireless access points edge effects
• Instability issues during handoff took careful
  calibration

11
Security

• User enters a SSID
• Moving towards LDAP
• Optional WEP

12
Wireless Network As Used in Education

• Increased engagement Students simultaneously
  answer a question using PDAs. that are posted on
  a large screen increasing students engagement
  and classroom experience
• Team-based collaboration input data as its
  generated download data, crunch numbers write
  lab report increasing efficiency
• Efficiency in teaching notes delivered to
  students over wireless means allows students to
  focus more on discussion and less on
  transcribing. Need to change teaching style to
  more fluid to allow for more discussion from
  students

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Benefits to Students

• Scheduling
• Collaboration
• Frequent less intrusive messaging
• Prompt message responses
• Be able to work in a social setting
• Work remotely
• Increased accessibility to professors and
  teammates
• More efficient and faster problem solving

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Benefits to Professors

• Professors can answer questions in bulk
• Work from home, the office, the class or while
  traveling

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The Voice Part of VoIPStudents Use

• 1,000 Ciscos IP Softphone
• 80 Ciscos 7920 wireless VoIP phones
• 100 Vocera Comm. Hands-free Voice Communicators
• Dartmouth to Converge Data Transfer of Data,
  Voice Cable Over One Line
• 10 Fold Increase in Bandwidth
• Upgrades in Network Intelligence and Equipment

16
Dartmouth Future

• To Double the Number of APs
• To Purchase 1,000 Arubas APs and an Estimated 7
  WLAN Switches as a Less Expensive Alternative to
  Cisco
• Contract to Purchase 600 SymPhone Clients

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References

• http//www.educause.edu/ir/library/powerpoint/LIVE
  056.pps
• http//www.educause.edu/ir/library/pdf/ers0202/cs/
  ecs0209.pdf
• http//www.computerworld.com/mobiletopics/mobile/t
  echnology/story/0,10801,91215,00.html
• Knapp, Susan, Internet Phones Have Arrived,
  Dartmouth News, 04/18/03
• Knapp, Susan, Software Phones at Dartmouth
  09/19/03

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IAAP 802.11f

• Allows Moving Between Access Points
• Uses TCP and UDP to Communicate With Clients and
  Backend RADIUS Servers
• Supports Both 802.15 PANs 802.16 WMANs
• System to hand off Clients Information, Level of
  Authentication and Services From One AP to
  Another Eliminating the Need to Re-authenticate

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802.11k

• Once ratified, 802.11k would help IT build a
  better WLAN. IT will benefit from improved
  control of the airwaves, and users will get
  consistent network access, even when roaming
  fewer disruptions to applications and faster
  service as a result of improved WLAN
  utilization.
• Dan Simone, 802.11k Makes WLANS Measure Up,
  Network World 3/29/04

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802.11k How Does It Work

• Roaming decisions
• Site report
• RF channel knowledge
• Noise histogram
• Hidden nodes
• Client statistics
• Transmit Power Control (TPC)
• Non-802.11 devices

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802.16

• For Point to Multi-Point (PMP) Applications
• Broadband Wireless Access (BWA)
• Works in PHY and MAC Layers at 10-66 GHz sub
  11GHZ
• Supports Higher Level Protocols
• IP, Ethernet, ATM etc.
• 268 mbps Each Way

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802.16

• Alternative to T-1 Lines Connecting Offices
• Variable Length PDUs
• Concatenate MAC PDUs Single Burst Saves PHY
• Concatenate Service Data Units (SDUs) Single
  MAC PDU Saves MAC Overhead
• Fragmentation of PDUs for QoS
• Uses Either TDD or FDD

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802.16a Wireless MAN

• Supports Multi-Media Applications
• Non LOS Last Mile Applications
• 2-11GHz
• 75 M bit/sec
• Up to 31 Mi.
• Offers Triple-DES Encryption

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802.16e Nomadic Applications

• To Increase Broadband Wireless Access (BWA) in
  MANs
• Seeks to Have Both High Data Rate of WLANs and
  High Mobility of WANs
• Support Mobility at 75-93 MPH
• Based on Current WiMax Standard
• Operates in Licensed 2-6 Bands

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802.20 WMANs

• Similar in Practice to 802.16e
• Data Rates of 1 Mbs to Rival DSL/Cable
• Range of 15km
• Possible Deployment in High Speed Trains
• Direct Competitor for 3G Cell Phones or
• Possible Overlay for Cell Phones Networks
• To Operate Below 3.5GHz

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802.22 (WRAN)Wireless Regional Area Networks

• Interoperable 802 Multivendor Wireless
• Create Competition in Broadband Access
• Offer Broadband Other Services to Sparsely
  Populated Areas
• Prevent Interference to Incumbent Licensed TV
  Services
• Offers Bigger Pipe for Current 802.11
• Complement 802.16 (WMAN)

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How Does 802.22 WRAN Work?

• Sets Requirements for MAC and PHY
• To Use TVs White Space Frequencies of
• 54-865 MHz
• 40km Propagation
• Very Attractive for Sparsely Populated
  Communities

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Pros of Cell/Wi-Fi Phone Combo

• Cell Providers Wi-Fi Vendors Cooperating to
  Create Product
• Wi-Fi Phones Easier to Program Personalize
• Projected Increase in Mobile or Roaming VoIP

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Cons of Mobile VoIP

• The problems are complex because VoIP over Wi-Fi
  combines the issues of wireless LANs (WLAN) with
  those of IP telephony.
• Tim Green, Mobile VoIP Set to Roam Even Wider,
  Network World, 1/17/05
• Dropped Calls Between APs
• Voice Quality
• Barriers in Buildings
• Wi-Fi Phones High Power Use

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• GSM/GPRS
• 802.11b
• Bluetooth
• IrDA
• USB
• Two Wi-Fi/Cell Phone Combo Products
• HP iPAQ 6315
• O2 xda II mini

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References

• http//standards.ieee.org/announcements/pr_80222.h
  tml
• http//www.nwfusion.com/details/7372.html?def
• http//standards.ieee.org/cgi-bin/status?wireless
• http//www.nwfusion.com/news/2005/011705specialfoc
  us.html
• http//www.nwfusion.com/news/2005/0308vwlan.html
• http//www.wi-fiplanet.com/columns/article.php/307
  2471
• http//www.wimaxforum.org/technology
• http//telecomm.boisestate.edu/ntcomm425.spring.20
  05/StudentPresentations/IAPP20and20BSU20Roaming
  20Gary20Umland.ppt