17_VoIP Over WLAN (Voice Over IP Over Wireless Local Area Network)_2004

5/21/2018 17_VoIP Over WLAN (Voice Over IP Over Wireless Local Area Network)_2004

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VoIP over WLAN

(Voice over IP over Wireless Local Area Network)

Diplomityseminaari 1.6.2004

Heikki Hintikka at Song Networks Oy

Supervisor: Professor Heikki Hmminen

Instructor: Pauli Saari, Quality Management Director


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4.8.2014 VoIP over WLAN 2

Contents

The concept of VoIP over WLAN Aims of research, main objectives

WLAN

Basics, factors of success, standards and future

VoIP

VoIP and speech, protocols, QoS

Security

standards & methods, currently (encryption, authentication), future

Devices and products

Deployment environments

example of hotspot, SOHO environment

provisioning model

TESTING (Access Link & SOHO environment)

Markets and forecast


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VoIP over WLANthe concept

VoIP WLAN

Free phone calls over the Internet

No toll quality voice service like PSTN

Used in many enterprise environments

QoS factors very important for voice quality

Wireless broadband up to 54 Mbps

Data rates depend on distance

Standards evolving to meet user needs

Still challenges to face


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Thesis ToC

1 INTRODUCTION 1.1 Background to VoWLAN

1.2 Main issues in VoWLANs

1.3 Problem definition

1.4 Scope of study

1.5 Methodology

1.6 Structure of the study

2 WLAN

3 VoIP

4 Usability and Deployment

5 Testing of VoWLAN (SOHO environment)

6 Market and Business Analysis 7 Trends and Forecast


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WLAN (Wireless Local Area Network)

Benefits: wireless broadband, low cost equipment, easy-to-use

Drawbacks: Issues with security, QoS, usability (roaming)

3 types of architecture: Infrastructure

Ad-hoc

Mesh networking

Radio interface: frequency bands, channels

Standard family (IEEE 802.11) evolving


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IEEE 802.11 (WLAN) standards

802.11bDSSS

11 Mbps

2,4 GHz802.11a

54 Mbps 5 GHz

OFDM 802.11h

802.11f

802.11e

802.11i

802.11g


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WLANs four Ss main criterias

Security

user data integrity, secure authentication, encryption

Service quality real-time applications (voice/video), QoS

Support

operational, functionality, interoperability, performance

Scalability flexible, easy-to-use services, develop higher quality


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VoIP

Voice over IP networks (RTP/UDP), Internet best-effort SIP (IETF) and H.323 (ITU-T), multimedia support

Gaining market space in enterprises

--> support for only one network

An important component in video calls

Many challenges when transmission media is wireless QoS parameters (delay, jitter, packet loss)

Security features increase delay etc.


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QoS (Quality of Service)

These QoS components ensure the performance

of voice calls across a data network:

Delay (ms)

Jitter (ms)

Packet Loss (%)

Congestion in access points

WLANs get disturbance of external factors

Bluetooth, microwave oven, trees, obstacles

Channel overlapping

Handover improvement


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Security

Encryption mechanisms

WEPWired Equivent Privacy, weak nowadays

TKIPTemporary Key Integrity Protocol, taken WEPs place

CCMP / AES (in 802.11i)

Authentication

WPA (Wi-Fi Protected Access): port-based 802.1X + EAPs/TKIP

802.11i: WPA extension plus other features CCMP/AES

pre-authentication


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Evolution of WLAN security

802.11i

RC-4

WEP

MD5

802.1X

WPA

RADIUS

EAPs

PEAP

EAP-?

EAP-SIM

EAP-

MD5

LEAP

EAP-TLS

EAP-TTLSTKIP

CCMP

MIC

AES

WEP


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Devices and products

End user devices: PDAs, laptops, smart phones etc.

Network elements

Usability important

Features and characteristics:

interoperability

seamless handover

roaming

hybrid solutions


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Deployment environmentsHotspot example

Internet

HOTSPOT

Enterprise

WISP /

WISPaggregator

Local services

Fixed line

aggregatorAAA server

CELLLAR OPERATOR

(GSM/CDMA)

RADIUS

interworking GW

HLR / HSS /

RADIUS

GW

Access

controller

Router

Core network

packet data GW

PEAP / EAP /

RADIUS

802.1X / EAP


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Provisioning modelone bill roaming

Hotspot operatorHome entityRoaming intermediary

AAA server

AAA serverAAA server

direct AAA exchange

Internet

Access

cotroller GW

RADIUS

User data

Billing

End user Roaming user


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Testing of VoIP over WLAN - SOHO

Prioritizing VoWLAN in SOHO environment

Internet

router / CPE

edge router

WISP

operator

network

Test premises

DSLAM

SIP-based

VoIP server

VPN server


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Results: QoS parameters

delay and jitter

Downstream Delay

-0,100000

-0,080000

-0,060000

-0,040000

-0,020000

0,000000

0,020000

0,040000

Time (s)

Delay(s)

Downstream Jitter

0,000000

0,020000

0,040000

0,060000

0,080000

0,100000

0,120000

Time (s)

Jitter(s)


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VoIP prioritizing in hotspots


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Markets & forecast

Markets are growing fastprice erosion

Multiple manufacturers making devices

inter-network capabilities (GSM/GPRS/CDMA) WISPs, network operators, alliances,

roamingcoverage/clients

Competitors? 3G, UWB, Bluetooth, WiMAX

Different stakeholders in business


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Conclusions and future work

Conclusions Overcoming QoS and security issues in VoWLAN designs and

implementations

Overcoming security flaws will be addressed by upcoming IEEE

802.11i standard

technical and economic business issues dealt with

Essential for providing QoS is to priritize VoIP streaming

Future work

traffic congestion in QoS guaranteed networks, where 802.11e has

been implemented Roaming, handover time reducement, standard affects in general

Support and interoperability

17_VoIP Over WLAN (Voice Over IP Over Wireless Local Area Network)_2004

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