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VoIP in WLAN‘s QoS and mobile devices David Jackisch Outline Quality of Service CISCO Solution Mobil Devices Scenarios 2 David Jackisch Quality of Service WLAN is shared medium QoS is important for wireless mobile IP phone calls

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voip in wlan s

VoIP in WLAN‘s

QoS and mobile devices

David Jackisch

outline
Outline
  • Quality of Service
  • CISCO Solution
  • Mobil Devices
  • Scenarios

2

David Jackisch

quality of service
Quality of Service
  • WLAN is shared medium
  • QoS is important for wireless mobile IP phone calls
  • Delay: up to 150ms acceptable for most user applications, above 400ms unacceptable
  • Jitter (75ms), delay, packet loss (3%)
  • Optimising the path of a voice packet
  • Technique: buffers, admission ctrl,
  • Security issues WPA…

3

David Jackisch

quality of service 2
Quality of Service (2)
  • Reliability
  • Availability (data networks 94% ~ 22 days/year)
  • Real-time
  • DiffServ – priority in data traffic, service classes
  • Echo cancellation
  • Some proprietary standards
  • -> 802.11e

4

David Jackisch

ieee 802 11e
IEEE 802.11e
  • Defines QoS for 802.11 wireless networks
  • Due packet delay/loss and jitter QoS is needed
  • Mechanism for prior data streams
  • EDCF defines 8 traffic categories, software update
  • HCF allocates timeslots, hardware upgrade necessary
  • Implemented 2004

5

David Jackisch

cisco implementations
CISCO Implementations
  • Skinny client control protocol (SCCP) for communicating with Call Manager IP PBX
  • CISCO Aironet WLAN infrastructure is expensive
  • In future: push to talk, WPA, layer-3 roaming, SIP, voice dial…

6

David Jackisch

a a a
A A A
  • Authentification, Authorization, Accounting
  • Possibilities: use of SIM cards, electronic keys
  • Different invoices from service provider, internet provider…

7

David Jackisch

mobile devices
Mobile Devices
  • Notebook or PDA with soft phone
  • Inexpensive, effective
  • Not comfortable in use
  • UMA (unlicensed mobile access) seamless to WLAN, GSM/GPRS, Bluetooth

8

David Jackisch

mobile devices 2
Mobile Devices (2)

WiFi phones

  • ZyXEL P2000W
    • 802.11b WLAN Standard
    • SIP v2
    • G.711 G.729a voice coding
    • 802.11 Ad hoc modus
    • Range 300m/75m
    • 64/128bit WEP encryption
    • QoS TOS/DiffServ

9

David Jackisch

mobile devices 3
Mobile Devices (3)

Dual mode phones

  • MOTOROLA CN620
    • GSM and WLAN support
    • MS Windows CE
  • T-Mobile MDA3
    • PDA with GSM
  • NOKIA Communicator 9500

10

David Jackisch

scenarios
Scenarios
  • Last mile for telecommunication service providers
  • Connecting new infrastructure with the core network
  • Backup for cellular phone in emergency situations
  • Company telecommunication network, intranet
  • Access from all over the world to corporate network

11

David Jackisch

summary
Summary
  • Cheaper to operate, maintain and upgrade
  • More powerful, flexible and feature-rich than conventional devices currently in the market
  • One telephone number in every location
  • New markets for hardware producers, service providers and network providers

12

David Jackisch

sources
Sources

[1] www.google.de

[2] www.networkcomputing.de/cms/fileadmin/ nwc/downloads/pdf/itwissen_ebook_voip.pdf

[3] www.motorola.com

[4] www.siemens.de

[5] www.zdnet.com

[6] www.ivs.tu-berlin.de/Lehre/WS0304/TIA/Material/09-QoS-Teil2.pdf

[7] www.cisco.com

13

David Jackisch

slide14
Thank you. Questions?

14

David Jackisch