Service Oriented Architecture For Dummies®

Chapter 9. The Enterprise Service Bus

In This Chapter

• Catching the enterprise service bus

• Figuring out ESB components

• Rules of the road for the ESB

You or someone you know probably has had the experience of taking a bus — maybe to school or to work. The thing about buses is that no matter how old you are or how smart you are or what clothes you wear or how much stuff you schlep with you, you get on the bus the same way, and the bus takes you where you want to go regardless. After you set foot on the bus, you also know approximately how long it will take to arrive at your destination (barring any accidents). If traffic is backed up, the drivers will take alternative routes to get you where you're going. Believe it or not, if you understand this, you're on your way to understanding an enterprise service bus (ESB).

ESB Basics

The enterprise service bus is the communications nerve center for services in a service oriented architecture. As you can see in Figure 9-1, ESBs are designed to act as intermediaries between the SOA components, infrastructure services, and business processes. Admittedly, ESBs were not designed specifically to act as SOA intermediaries, but because a service oriented architecture needs a devoted intermediary in order to scale up for large numbers of users, an ESB ended up being just what the doctor ordered for SOA environments.

Why a bus

The word bus comes from the Latin omnibus, which means "for all." Horse-drawn omnibuses were one of the earliest forms of public transportation. ...