INTRODUCTION:Goal, Reasons for writing this document, How to read this document

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TECHNOLOGICAL BACKGROUND:Components, Terminal, Protocols, SIP >>

[IPTelephony Cookbook] / Introduction

Introduction //>

> 1.1 Goal

The IP Telephony Cookbook is a reference document addressing technical issuesfor the setup of

IP Telephony solutions. Itsgoal is to provide the usercommunity with guidelinesand information

aboutthe IP Telephony world andeverything related to it.Since the Cookbook is intended to be

a technical document, the main targetaudience are the networkengineers and system

administrators at universities and nationalresearch and education networks (NREN); however,

university students and researchers mayfind it useful, both for enriching their technological

background as well as for findinginformation about advancedresearch topics and projects in the

Europeancommunity.

> 1.2 Reasons for writing thisdocument

Members of the NREN community askedTERENA to start an investigationinto IP Telephony

in September 2001.The responsewas very positive andsuggestions were made to co-ordinate

thecreation of a cookbook withrecommendations for setting up IP Telephony solutions at

university- and national-level, withinformation about protocolsand the interoperability of

equipment as well as about integration withthe existing international hierarchiesfor IP

videoconferencing.For this reason, a number of people in the TERENAcommunity with

significantexpertise in the area of IP Telephony decided to undertakethis task and to compose

this document,The IP TelephonyCookbook.

> 1.3Contents

The IP Telephony Cookbook is divided intochapters, which guide thereader through increasing

levels of knowledge of the IP Telephonyworld.This first chapter containsintroductory

informationand gives details of thecontents of the Cookbook,useful tips on how to readthis

document and techno-economic considerations.Chapter 2 explains the technological

backgroundneeded in order to understandthe topics addressed in therest of theCookbook.This

chapterdescribes the basic IP Telephony components andgives an overview of the IP Telephony

protocols.Chapter 2 ends with additional considerations on call routingand perspectivesabout

thefuture. Chapter 3 gives a high-level overview of scenarios a usermay face when building an

IP Telephony environment. Details aregiven to explain what a particularscenario is about, what is

needed in order to deploy it andwhat needs it is serving.Thenext three chapters (Chapter 4,

Chapter 5 and Chapter 6) detail how to set up IP Telephony services;those chapters givethe

readerthe chance to learn how to set up basic services,advanced services (still telephony-centric)

andvalue-added services (withrespect to classic telephonyservice). Chapter 7 is aboutthe

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[IPTelephony Cookbook] / Introduction

integration of global telephony, describingthe technological solutions availablefor the integration

of global IP Telephony and thesuccessful replacement of classictelephony. Chapter 7 reports on

today's situation, as well as migration andfuture trends.The lastchapter contains the

regulatory/legal considerations users have to be aware of when moving fromclassic telephony to

IP Telephony.The topics here relate to the regulation of IP Telephony in Europe and in other

countriesoutside the European Union. A large number of legal issuesfor classic telephonyare

detailed,from licensing to unbundling, andtheir mapping to the IP world. Finally, the IP

TelephonyCookbook contains twoannexes. Annex A lists anddescribes current and future IP

TelephonyProjects in Europe. Annex B gives the reader usefulinformation about IP Telephony

hardwareand software, reporting `handson' experience (i.e., howthe devices performed, how

goodtech-support was, what werethe workarounds for some of the problems faced,etc).

> 1.4 How to read thisdocument

Sincethe IP Telephony Cookbook is a technical reference document, it must include guidelines

forusers who do not want to read the whole document, so that they can findthe information

theyneed. In this section, we give the reader tips on how to read the document in order to

retrievethe information needed as fast as possible; for a detailed overview of thecontents of the

Cookbook,please refer to the previous section.To speed up the informationretrieval process,

eachreader should identify himself as belonging to one of the followingthree 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

necessarybackground to understand therest of the cookbook.Readers who are interested in

setting up an IP Telephony service shouldread Chapter 3 to have a clear picture of thepossible

scenariosoffered by IP Telephony andtarget the one best-suited to the needs of their

environment.The second group of readers mayskip the previously-mentioned chapters, but

Chapter 3 may be of some interest to them; the main focus of thisgroup of users is more likely to

be in Chapter 4 and Chapter 5 which give tips andhelp in setting up an operativeservice.The

thirdgroup of users is likely to be more interested in the `valueadded' services availablenowadays

with IP Telephony (Chapter 6) or in the integration problems of an IP Telephonyarchitecture

that is widely distributed across multiplesites and organisations(Chapter 7). All threegroups of

usersmay find useful information in Chapter 8 and Europeanproject information in Annex A.

Last but not least, the list of products and testingexperience reported in Annex B is a must for all

userswho do not want to risk making the wrong choices in a buying decision.

> 1.5Techno-economic aspect of movingfrom classic telephony to VoIP

Many institutions are facing investmentdecisions with respect to replacing or expandingtheir

existing telephony infrastructure, which currently consists mainly of largePBXs with proprietary

phonesand interfaces. As is theresuch a clear trend to replace old-style (TDM) PBXswith IP

Telephonyones, it is important thatthere is a guide on how to attach such an IP Telephony

solution to the existing network. IP connectivitycan be used as the basisfor establishing good

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[IPTelephony Cookbook] / Introduction

communicationbetween scientists thatmight not use traditional, still relativelyexpensive,

long-distancecalls as extensively as they could use IP Telephony. Even where financial constraints

arenot the driving force,the potential for enhancing IP Telephony with additional servicesthat

support scientific co-operation makes IP Telephony an attractive solution.

IP Telephony can provide a number of benefits beyond replacing existing PBX/PSTN telephony:

Enhancedspeech quality

The PSTN (and most PBXs)are limited to 3.1 kHz,8-bit/sample audio. It is likelythat future

IP phones can provide CD quality and possibly even stereoaudio. Even where the additional

bandwidthrequired for this extremelevel 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;

Improved availability

Thereare many aspects of availability. Lowering thecost can make telephony more available to

low-budgetactivities. Redundancy canprovide as good as (or evenbetter) reliabilitythan

traditional telephony. Integrating telephony withlocation-based computing and group-

awarenesssystems can make thecommunication partners much more `available', or providethe

means to transfer communication to a point in time where it is more appropriate thanthe usual

interrupt-driventelephone call;

Improvedcoverage

In a similar argument, IP Telephony can be made available in places where traditional phones

areoften not available in a university, e.g., labsettings (in particular, studentlabs). Also, many

universitiesstill consider the cost of phone installations high enough to force their employees to

sharephones in a common office, again,not necessary whenworkstation-based IP Telephony is

used;

Improved mobility

It is very easy to move an IP phone to another room.There is no need to deal with ports on the

PBXand change dial numbers.Simply plugging it into an ethernetsocket in a new room

makes it available;

Improved media integration

IP phones can be enabled to addmedia to an ongoing call as required,e.g., viewing a picture or

drawing on a whiteboard. Using workstationsthemselves as IP phones can facilitate providing

thisfunction, whereas thestandards are not yetthere for coupling traditional phonesand

workstations;

Newservices

As IP Telephony evolves, it can be used to provide new services(like user-definedcall

processing) or to integrate existing concepts, e.g.,Presence, Location Awareness or Instant

Messaging.Because of the openstandards available forthese services, they neednot to be

limited to vendor-specific solutions. In otherwords, it can be much easier to deal with issues

such as CTI (Computer Telephony Integration) and so pave the way to a completely new way

of understanding telephony;

Research

As mentioned before, the protocolsand standards used for IP Telephony are open andpublicly

available.Thisallows research institutions to work on their own services andsolutions.

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[IPTelephony Cookbook] / Introduction

It is important to point outthat before introducing IP Telephony into the network of an

organisation;several issues unknown to the old telephone systemhave to be taken intoaccount.

A rough, non-exhaustive list may include addressing (special subnet/VLANfor phones), Quality

of Service (QoS), security, positioning of gateways, interfacing of firewalls and,last but not least,

maintenance of the system (backups,spares, etc., - somethingnot very common in thelegacy

PBXworld).

Withregard to the economic aspects,the `packetisation' of voiceusing Voice over IP has given

rise to new international telecommunications carriers.Thesecarriers have distributed network

architecturesusing the Internet as a platform.VoIP networks have an architecture offering the

most efficient way to implement multilateral telecommunications agreements, thuseliminating

theneed for carriers to engage in hundreds of bilateral traffic agreements as are requiredbetween

traditional circuit-switched PSTN carriers. Moreover, since packet networks aresoftware driven,

theycan be configured more dynamically than traditional PSTN networks. For example,with a

globalvoice over packet network,new destinations areavailable to all users on the network,

withoutthe need for constant additional investment.

IP Telephony telecommunications companiesmay expand the availability of services to a wider

audience. IP Telephony technologies can be used to build voice networks more rapidly and at a

lowercost than legacy PSTNsystems. Easier deployment of Voice over IP networks can bringthe

benefits of telecommunications to more people in a muchshorter timeframe than would be

possiblewith conventional PSTN networks. At the same time, nothaving to buildextensive

infrastructureprovides the motivation formany companies to migrate to IP Telephony

architectures.

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