> 1.1 Goal
The IP Telephony Cookbook is a reference document addressing technical issues for the setup of IP Telephony solutions. Its goal is to provide the user community with guidelines and information about the IP Telephony world and everything related to it. Since the Cookbook is intended to be a technical document, the main target audience are the network engineers and system administrators at universities and national research and education networks (NREN); however, university students and researchers may find it useful, both for enriching their technological background as well as for finding information about advanced research topics and projects in the European community.
> 1.2 Reasons for writing this document
Members of the NREN community asked TERENA to start an investigation into IP Telephony in September 2001.The response was very positive and suggestions were made to co-ordinate the creation of a cookbook with recommendations for setting up IP Telephony solutions at university- and national-level, with information about protocols and the interoperability of equipment as well as about integration with the existing international hierarchies for IP
videoconferencing. For this reason, a number of people in the TERENA community with significant expertise in the area of IP Telephony decided to undertake this task and to compose this document,The IP Telephony Cookbook.
> 1.3 Contents
The IP Telephony Cookbook is divided into chapters, which guide the reader through increasing levels of knowledge of the IP Telephony world.This first chapter contains introductory information and gives details of the contents of the Cookbook, useful tips on how to read this document and techno-economic considerations. Chapter 2 explains the technological background needed in order to understand the topics addressed in the rest of the Cookbook.This chapter describes the basic IP Telephony components and gives an overview of the IP Telephony protocols. Chapter 2 ends with additional considerations on call routing and perspectives about the future. Chapter 3 gives a high-level overview of scenarios a user may face when building an IP Telephony environment. Details are given to explain what a particular scenario is about, what is needed in order to deploy it and what needs it is serving.The next three chapters (Chapter 4, Chapter 5 and Chapter 6) detail how to set up IP Telephony services; those chapters give the reader the chance to learn how to set up basic services, advanced services (still telephony-centric) and value-added services (with respect to classic telephony service). Chapter 7 is about the P.7
[IP Telephony Cookbook] / Introduction
integration of global telephony, describing the technological solutions available for the integration of global IP Telephony and the successful replacement of classic telephony. Chapter 7 reports on today's situation, as well as migration and future trends.The last chapter contains the regulatory/legal considerations users have to be aware of when moving from classic telephony to IP Telephony.The topics here relate to the regulation of IP Telephony in Europe and in other countries outside the European Union. A large number of legal issues for classic telephony are detailed, from licensing to unbundling, and their mapping to the IP world. Finally, the IP
Telephony Cookbook contains two annexes. Annex A lists and describes current and future IP
Telephony Projects in Europe. Annex B gives the reader useful information about IP Telephony hardware and software, reporting ‘hands on’ experience (i.e., how the devices performed, how good tech-support was, what were the workarounds for some of the problems faced, etc).
> 1.4 How to read this document
Since the IP Telephony Cookbook is a technical reference document, it must include guidelines for users who do not want to read the whole document, so that they can find the information they need. In this section, we give the reader tips on how to read the document in order to retrieve the information needed as fast as possible; for a detailed overview of the contents of the Cookbook, please refer to the previous section.To speed up the information retrieval process, each reader should identify himself as belonging to one of the following three groups:
- readers who have no knowledge of IP Telephony;
- readers who have basic knowledge of IP Telephony;
- readers who have advanced knowledge of IP Telephony.
Readers belonging to the first group should, first of all, refer to Chapter 2 to acquire the necessary background to understand the rest of the cookbook. Readers who are interested in setting up an IP Telephony service should read Chapter 3 to have a clear picture of the possible scenarios offered by IP Telephony and target the one best-suited to the needs of their environment.The second group of readers may skip the previously-mentioned chapters, but Chapter 3 may be of some interest to them; the main focus of this group of users is more likely to be in Chapter 4 and Chapter 5 which give tips and help in setting up an operative service.The third group of users is likely to be more interested in the ‘value added’ services available nowadays with IP Telephony (Chapter 6) or in the integration problems of an IP Telephony architecture that is widely distributed across multiple sites and organisations (Chapter 7). All three groups of users may find useful information in Chapter 8 and European project information in Annex A.
Last but not least, the list of products and testing experience reported in Annex B is a must for all users who do not want to risk making the wrong choices in a buying decision.
> 1.5 Techno-economic aspect of moving from classic telephony to VoIP
Many institutions are facing investment decisions with respect to replacing or expanding their existing telephony infrastructure, which currently consists mainly of large PBXs with proprietary phones and interfaces. As is there such a clear trend to replace old-style (TDM) PBXs with IP
Telephony ones, it is important that there is a guide on how to attach such an IP Telephony solution to the existing network. IP connectivity can be used as the basis for establishing good P.8
[IP Telephony Cookbook] / Introduction
communication between scientists that might not use traditional, still relatively expensive, long-distance calls as extensively as they could use IP Telephony. Even where financial constraints are not the driving force, the potential for enhancing IP Telephony with additional services that support scientific co-operation makes IP Telephony an attractive solution.
IP Telephony can provide a number of benefits beyond replacing existing PBX/PSTN telephony: Enhanced speech quality
The PSTN (and most PBXs) are limited to 3.1 kHz, 8-bit/sample audio. It is likely that future IP phones can provide CD quality and possibly even stereo audio. Even where the additional bandwidth required for this extreme level of quality cannot be provided; modest codecs such as G.722 (7 kHz speech bandwidth) can be used to provide better quality than conventional telephony;