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><A
NAME="JABTDG-PREFACE"
>Chapter 1. Preface</A
></H1
><DIV
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><DL
><DT
><B
>Table of Contents</B
></DT
><DT
><A
HREF="c7.htm#JABTDG-PREFACE-SECT-1"
>What Is Jabber?</A
></DT
><DT
><A
HREF="x53.htm"
>The History Of Jabber</A
></DT
><DT
><A
HREF="x118.htm"
>IM System Features</A
></DT
><DT
><A
HREF="x151.htm"
>What's Inside</A
></DT
><DT
><A
HREF="x217.htm"
>The Software</A
></DT
><DT
><A
HREF="x270.htm"
>Conventions Used in This Book</A
></DT
><DT
><A
HREF="x303.htm"
>How to Contact Us</A
></DT
><DT
><A
HREF="x317.htm"
>Acknowledgments</A
></DT
></DL
></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="JABTDG-PREFACE-SECT-1"
>What Is Jabber?</A
></H1
><P
>Well, that is certainly a good question with which to start this book.
Depending on who you ask, the following answers may be forthcoming:</P
><P
></P
><UL
><LI
><P
>Jabber is a technology</P
></LI
><LI
><P
>Jabber is a protocol (or set of protocols)</P
></LI
><LI
><P
>Jabber is an XML-based Instant Messaging (IM) system</P
></LI
><LI
><P
>Jabber is an <I
CLASS="EMPHASIS"
>implementation</I
> of the set of protocols</P
></LI
><LI
><P
>Jabber is an idea whose time has come.</P
></LI
></UL
><P
>In fact, all these answers are right. Jabber is a set of protocols expressed
within XML that provide people and applications with the ability to
converse. Sure, TCP sockets, STDIN/STDOUT, infrared, voice input and
teletype mechanisms all allow people and applications to converse; the
difference is that Jabber provides a structured, extensible framework
for exchanging all kinds of information.</P
><P
>This is all rather abstract. What do we mean by "extensible framework
for exchanging information?" Taking it one word at a time:</P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
>Extensible</DT
><DD
><P
>Jabber's substrate is XML. XML is inherently extensible in the sense that
tags can be added in a hierarchical sequence. Namespaces in XML allow us
to keep track of the meaning and organization of these tags.</P
></DD
><DT
>Framework</DT
><DD
><P
>You can put together a system for exchanging information using many different
tools. The point about the "framework" is that the information exchanged and
the entities that are exchanging it are contextualized, bringing meaning
and structure to the interactions.</P
></DD
><DT
>Exchanging</DT
><DD
><P
>Conversation is two-way, and it takes many forms: question and answer,
notification, compartmentalized discussion, and simple chat. Jabber supports
all these different types of conversation, and more.</P
></DD
><DT
>Information</DT
><DD
><P
>One doesn't really say that <I
CLASS="EMPHASIS"
>information</I
> is exchanged
in a conversation, but when you bring applications into the mix of
conversing entities, it may well be the case. And it's not just information
exchanged in the form of conversations, but also information about the
entities themselves that flows across this context framework.</P
></DD
></DL
></DIV
><P
>It goes without saying:</P
><P
></P
><UL
><LI
><P
>Jabber is an IM system</P
></LI
></UL
><P
>IM was Jabber's original raison d'etre. Many deployments of Jabber software
are to provide IM services,
but Jabber is more than IM. Certainly more than the phrase
"Instant Messaging" represents. In this book you'll find out why
this is so, and how you can deploy solutions with Jabber that are
more than mere chat. But most importantly, Jabber is fun!</P
><P
>Like chess, which has a small set of rules but countless game possibilities,
the technologies employed in Jabber and the Jabber protocol itself are
straighforward. The possibilities are almost limitless. Furthermore,
because of a fundamental design feature
<A
NAME="AEN50"
HREF="#FTN.AEN50"
>[1]</A
>
(you might call it a "philosophical" angle),
implementing Jabber-based solutions to your problems can be fun—really!</P
></DIV
></DIV
><H3
CLASS="FOOTNOTES"
>Notes</H3
><TABLE
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><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="5%"
><A
NAME="FTN.AEN50"
HREF="c7.htm#AEN50"
>[1]</A
></TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
WIDTH="95%"
><P
>That the complexity of a Jabber implementation should always remain in the
<I
CLASS="EMPHASIS"
>server</I
>, leaving the clients simple and clean</P
></TD
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