This page explains the interest of a solution such as Petals ESB and in which situations its brings an additional value.
To ease the comprehension, it also introduces some scenarios involving Petals ESB within Information Systems.

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{note}NDLaurent : Première version de la page What is. La première partie sera à terme déplacée dans une page dédiée, visible depuis l'accueil du wiki. De même, la description actuelle déborde un peu sur la présentation générale de la plateforme Petals (à créer). {note}
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h1. What is an Enterprise Service Bus?

h2. From EAI to ESB

The notion of enterprise service bus was born several years ago, as a renewal of Entreprise Applications Integration solutions.
The Enterprise Applications Integration encompasses all middleware products, aiming for a better communication between one's applications, thus sparing costly point-to-point dedicated interfaces, and/or allowing better adequation of one's IS to enterprise organisation.
Traditionally, such solutions were proprietary ones. In the recent years, several factors revealed the need for a new integration model: great increase in entreprise use of business softwares, boom of internet exchanges with clients/partners/administration, lack of interoperability between concurrent EAI solutions...
Due to all of this, a new wave of products emerged: the Enterprise Services Bus.

h2. ESB Technology Overview

An Enterprise Service Bus keeps the same core concept as traditional solutions, but brings major assets:
- standard integration interface: using a standard pivot format, such as XML;
- standard communication protocols;
- message routing;
- data transformation;
- services exposure for external exchanges.

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An enterprise service bus (ESB) consists of a software architecture construct which provides fundamental services for complex architectures via an event-driven and standards-based messaging-engine (the bus).
Source: [Wikipedia|http://en.wikipedia.org/wiki/Enterprise_Service_Bus]
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The general idea of an Enteprise Service Bus is to provide a full-featured platform answering integration, routing, transformation and exchanges in a flexible, interoperable and resilient way.
ESB are also a solution of choice for adoption of modern infrastructure, based on a Service Oriented Architecture (SOA).
[Read more about ESBs on Wikipedia|http://wikipedia.org/wiki/Enterprise_Service_Bus]

Beyond the inherent improvments of an ESB over traditional EAI solutions, Petals ESB uses a best-of-breed approach and open source development model to distinguish from other ESB solutions, bringing essential features.

h3. Natively Distributed Architecture

Most of EAI and ESB solutions are based on a centralized architecture. This choice brings simplicity of configuration and maintenance. One risk however is the great loss the company would sustain in case of serious problem with the middleware.
Choosing a middleware clusters reduce this risk but adds great complexity to the infrastructure.
Petals ESB chose the third way, using a P2P-like approach: the container can be installed on several machines, each one hosting its set of services, router and shared registry of services.
- high availability, thus SLA respect, thanks to replication of services on several nodes and intelligent routing;
- inherent load balancing.

h3. Light & Powerful

Petals ESB is entirely modular, making it a light platform, running without application server. Numerous components are already available for data exchange (FTP, SOAP, REST, POP...) and data manipulation (POJO, Quartz, XSLT, Talend...)
h2 Monitoring and Orchestration capabilities
By combining Petals BPEL/SCA service engines and our dedicated IDE, Petals Studio, you can easily assemble individual services to form business processes, with GUI and code validation.
Using notifications service engine, Petals View allows easy monitoring configuration, so that end business users can watch their business processes and analyse their efficiency.

h3. Standard and Open Source

Petals ESB is one of the few to be fully compliant with the Java Business Integration specification. It makes full use of standards protocols.
As an open source product, you can freely adapt it to fit your need, be it through a new component or container adaptation, or ask any expert to do it for you, without being bound to Petals Link (although we are probably the finest experts on these matters hehe).

h3. Ease of Use

Petals ESB is bundled with a [Web Console|webconsole], allowing graphical administration of services and nodes.

- capacité d'intégration pragmatique dans le système, trois cas principaux.
- intégration
- médiation
- peut-être mise en page pour chaque cas :

* schéma expliquant le concept, à sa droite Objectif > Produits utilisés
* paragraphe explicitant le concept
* lien vers fiche produit présentant exemple concret.
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