Introduction

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, mainly in National Research and Education Networks (NREN) and connected institutes, with guidelines and information about the IP Telephony world. Since the Cookbook is intended to be a technical document, the main target audience is the network engineers and system administrators; 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.

A first edition of the IP Telephony Cookbook was published by TERENA in 2004. The content is available online at http://www.terena.org/activities/iptel/contents1.html. The evolution of technology and continuous interest of the NREN community in this topic called for an update to the Cookbook. TERENA's Task Force on Enhanced Communication Services (TF-ECS) started working on this in 2007. More than a simple update of the previous Cookbook, the new edition is structured as a live document providing new recipes and deployment scenarios.

Reasons for writing this document

Recommendations for setting up IP Telephony solutions at university- and national-level, with information about protocols and the interoperability of equipment, are widely available on the Internet. However, the viewpoints are fragmented and usually centred on particular scenarios, either as a result of commercial interest or simply because they describe a particular solution. Little has been done to integrate such scenarios in a wider context, taking into account multi-domain aspects and an international hierarchy or interconnect architecture. For this reasons, 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.

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 and useful tips on how to read this document. Some techno-economic considerations may be found in the introductory section of the previous edition of the IP Telephony Cookbook. It is perhaps not surprising that most of these reflections were still valid in 2007.

Chapter 2 explains the technological background needed in order to understand the topics addressed in the rest of the Cookbook. As this type of basic information is widely available online, the authors decided to mainly include here references for further reading. The articles and documents referenced were chosen for their technical accuracy, with a preference for hosting sites that were expected to be long lasting.

Chapter 3 details the basic steps involved in setting up IP Telephony services inside an administrative domain. Advanced topics, such as peering across domains and value-added services, are introduced in chapters 4 and 5.

Annex A presents technical details on the IP Telephony services deployed by European NRENs and lists options for the their interconnection. Annex B is structured as a clearinghouse for hardware and software deployed by various IP Telephony and Enhanced Communication services in NRENs. By no means an exhaustive list of the options available on the market, this annex is meant as an indicator on who is using a particular tool. Based on this knowledge, NRENs or institutes looking into new deployments of a particular tool would know who to contact for hands-on experiences and opinions.

How to read this document

Since the IP Telephony Cookbook is a technical reference document, it must include guideline 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, consult the previous edition of the Cookbook and 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 and the third group of readers may access the Cookbook at will, depending on the type of problem for which they are looking for a solution. It should be noted by users in the second group that the inter-domain aspects involved in Chapter 4 and 5 may require a deeper understanding of the technical aspects involved. All three groups of users may find useful information in Annex A and B.