What is an enterprise service bus?
An enterprise service bus (ESB) is a pattern of middleware that unifies and connects services, applications and resources within a business. Put another way, it is the framework within which the capabilities of a business' applications are made available for reuse by other applications throughout the organization and beyond. The ESB is not a new software product — it's a new way of looking at how to integrate applications, coordinate resources and manipulate information. Unlike many previous approaches for connecting distributed applications, for example RPC or distributed objects, the ESB pattern enables the connection of software running in parallel on different platforms, written in different programming languages and using different programming models.
Examples of the enterprise service bus patterns exist today, built using existing integration tools available in the IBM Business Integration portfolio of products. For a business, an ESB can manage connectivity needs by providing standards based application integration with support for Web services, message based transport and mediation (transformation and routing) oriented toward a service based infrastructure (often referred to as a service oriented architecture).
Key characteristics of an enterprise service bus
An enterprise service bus can optimize information distribution within
an enterprise and beyond and may be built with integration middleware
products available today from IBM.
An enterprise service bus:
- Is standards-based
- Can enable all parts of a business to react instantly to new information
- Minimizes risk by using industry standard interfaces and protocols
- Overcomes differences in platform, software architecture and network protocols
- Assures delivery of transactions, even when systems and networks go off-line
- Re-routes, logs and enriches information without rewriting applications
- Provides an infrastructure that is highly distributed and yet can be managed centrally
- Can distribute data throughout your business and beyond to your customers and business partners
- Spans different operating systems, programming models, application types and locations
- Can be deployed incrementally, project by project, to better manage expense
- May combine new and existing technologies and standards
- Supports message, service and event oriented architecture
ESB（Enterprise Service Bus，即企业服务总线）是传统中间件技术与XML、Web服务等技术结合的产物。ESB提供了网络中最基本的连接中枢，是构筑企业神经系统的必要元素。
企业服务总线ESB就是一种可以提供可靠的、有保证的消息技术的最新方法。ESB中间件产品利用的是Web服务标准和与公认的可靠消息MOM协议接口(例如IBM的WebSphere MQ、Tibco的Rendezvous和Sonic Software的SoniCMQ)。ESB产品的共有特性包括:连接异构的MOM、利用Web服务描述语言接口封装MOM协议，以及在MOM传输层上传送简单对象应用协议(SOAP)传输流的能力。大多数ESB产品支持在分布式应用之间通过中间层如集成代理实现直接对等沟通。
企业服务总线（Enterprise Service Bus，ESB）的概念是从面向服务体系架构(Service -Oriented Architecture， SOA)发展而来的。SOA描述了一种IT基础设施的应用集成模型，其中的软构件集是以一种定义清晰的层次化结构相互耦合，其中，一个ESB是一个预先组装的SOA实现，它包含了实现SOA分层目标所必需的基础功能部件。