Performance Characterization of Voice over Wireless

LANsLionel PEREZ

June 2nd, 2005

Master Thesis Project - Lionel Perez – June 2005 — 2

Agenda

> Abstract

> Specific Tasks

> Available Material

> Achieved Tasks

> References

> Support

> Related Work

Master Thesis Project - Lionel Perez – June 2005 — 3

Abstract

> VoIP over WLANs, the « killer application »

> Inexpensive and convenient mobile telephony

> Good voice quality required for success

> Can IEEE 802.11 WLANs provide such quality?

Master Thesis Project - Lionel Perez – June 2005 — 4

More parameters than wired LAN !

> Loss, Delay, Jitter

> Impact of rate adaptation, power management on loss, delay, jitter

> Impact of encrypction on loss, delay, jitter

> Impact of RTS/CTS on loss, delay, jitter

> Association performance, Authentication performance,

> Roaming time, Rate adaptation time,

> QoS (EDCF, WMM, WMM-SA)

> Packet size

Master Thesis Project - Lionel Perez – June 2005 — 5

Abstract

> Purposes of the project:

• Characterize the performance of a telephony solution based on Voice over IP over Wireless LANs (VoWLAN)

• Conduct measurements and simulation to identify the most significant parameters impacting voice quality

• Market and Strategy requirements:– Avoid time and cost-intensive tests– Independence from OEMs

Master Thesis Project - Lionel Perez – June 2005 — 6

Proposed Tasks 1/2

> Learn about the relationship between traffic parameters (delay, jitter, packet losses) and voice quality (MOS ,E-model: R-Value)

> Explore different scenarios that directly impact these parameters:• the QoS mechanisms implemented (802.11e)?• the security features (802.11i)?• 802.11a,b or g ?• the codec (opt)?• the signalling protocol (opt)?

Master Thesis Project - Lionel Perez – June 2005 — 7

Proposed Tasks 2/2

> Perform measurements of these parameters under the different possible considerations

> Use the ns2 network simulator or other (OMNET++?) to model and simulate some of these configurations

>Define key tests to be conducted in order to ensure a given performance

Master Thesis Project - Lionel Perez – June 2005 — 8

Available Material

> The « alpha test »: the VoWLAN solution deployed in our premises

> The «platform» (testing lab)

> PCs and laptops equiped with NICs

> Wireless Switches, Access Points, Wifi phones

> Professional measurement tools:• 2 Veriwave Tests Units• Wildpacket’s Airopeek• Airmagnet Laptop• Ixia Ixchariot

Master Thesis Project - Lionel Perez – June 2005 — 9

Achieved Tasks

> Bibliographical Research Complete

> Read the key articles

> Understand the available tools

> Discover ns2

> During the internship:• Discover Alcatel’s VoWLAN Solution• Evaluate Sigmum Wiplan (Planning Software)• Conduct Site Surveys• Basic mock-up configuration• The VoWLAN toolkit

Master Thesis Project - Lionel Perez – June 2005 — 10

Related Work

> “Can I add a VoIP call?”, S. Garg and M. Kappes

> Voice over IEEE 802.11b Capacity, Coupechoux, Kumar, Brignol (Alcatel), 2004

> Simulation of 802.11e

> Basic security features (WEP)

> New QoS mechanisms?

> New Security mechnisms?

> New Power Management mechanisms?

Master Thesis Project - Lionel Perez – June 2005 — 11

Support

> Supervisor:• Michel Mouton

> Additional Support:• Jean-Michel Lauriol• Daniel Le Bars• The WLAN team: Architecture, QoS, Security,

Interoperability, OXE/OXO

Master Thesis Project - Lionel Perez – June 2005 — 12

Thank you.

Master Thesis Project - Lionel Perez – June 2005 — 13

OXE-WLAN solution

UA 850000

ACS 172.25.115.226

WLAN OmniAccess

SLK0 855000172.25.114.2109D:28

OmniSwitch Router

SVP Server (with GK)172.25.114.196

Management: Port 1 172.25.115.229Vlan 99Voice:Port 1 172.25.114.197Vlan 31Data:Port 1 172.25.114.34Vlan 30

CS 172.25.114.194GD 172.25.114.195

UA 850001

172.25.114.193

NAT : 172.25.114.210-.219

172.25.114.220-.229

SLK1 855001172.25.114.2119E:69

SLK2 855002172.25.114.212BE:01

IP 853000172.25.114.230

IP 853001172.25.114.231

SLK3 855003172.25.114.213DD:30

172.25.114.33

Vlan Voice:172.25.114.192255.255.255.192

Vlan Data:172.25.114.32255.255.255.240

Vlan Management:172.25.115.229255.255.255.240

172.25.115.225

Laptop172.25.114.35

Radius, TFTP172.25.115.232

OXE