IP Telephony Cookbook

Deliverable 1

Saverio Niccolini

University of Pisa

Dr. Rosario Giuseppe Garroppo

University of Pisa

Dr. Jörg Ott

Universität Bremen TZI

Stefan Prelle

Universität Bremen TZI

Dr. Jiri Kuthan

FhG Fokus

Dr. Sven Ubik

CESNET

Dr. Margit Brandl

Karl-Franzens-Uni Graz

Dimitris Daskopoulos

GRNET

Egon Verharen

SURFnet

Erik Dobbelsteijn

SURFnet

Near final


Table of Contents

1. Introduction
Goal
Reasons for writing this document
Contents
How to read this document
Techno-economic aspect of moving from classic telephony to VoIP
2. Technology Background
Components
Terminal
Server
Gateway
Conference Bridge
Addressing
Protocols
H.323
SIP
Media Gateway Control Protocols
Proprietary Signaling Protocols
Real Time Protocol (RTP) and Real Time Control Protocol (RTCP)
3. IP Telephony Scenarios
Introduction
Scenario 1: Long-distance least cost routing
Least Cost Routing - An example of integration
Scenario 2: Legacy PBX replacement
Scenario 2a: IP-Phone without PBX
Scenario 2b: Integration with legacy PBX systems
Scenario 2c: Full replacement
Scenario 3: Integration of VoIP and Videoconferencing
Integrating Voice and Video over IP - an example
4. Setting up basic services
5. Setting up Advanced Services
6. Setting up Value-Added Services
7. Global telephony integration
8. Regulatory / Legal considerations
9. European IP Telephony Projects
10. IP Telephony Hardware/Software

List of Figures

2.1. Scope and Components defined in H.323
2.2. H.323 protocol architecture
2.3. Discovery and registration process
2.4. Direct signaling model
2.5. Gatekeeper Routed call signaling model
2.6. Gatekeeper Routed H.245 control model
2.7. OPENLOGICALCHANNELACK message content
2.8. Supplementary services of the H.450-Series
2.9. External address resolution using LRQs
2.10. Sample H.323 Call Setup Scenario
2.11. UAC and UAS
2.12. Session Invitation
2.13. Registrar Overview
2.14. SIP Redirection
2.15. SIP Transactions
2.16. SIP Dialog
2.17. SIP Trapezoid
2.18. REGISTER Message Flow
2.19. INVITE Message Flow
2.20. BYE Message Flow (With and without Record Routing)
2.21. Event Subscription And Notification
2.22. Instant Messages
2.23. Application Scenario for Media Gateway Control Protocols
2.24. RTP Header
3.1. Traditional separation of data and telephony between locations
3.2. Integration of data and telephony between locations
3.3. Least cost routing architecture
3.4. Legacy PBX which trunks to the PSTN
3.5. IP-Phone to IP-Phone without PBX
3.6. Integration of IP-Telephony with legacy PBX system
3.7. IP-Telephony fully replacing PBX
3.8. Integrated Voice and Video over IP architecture at SURFnet offices