Enterprise Service Bus (ESB) - Guide to Cloud Computing for Business and Technology Managers - page 189

9
Enterprise S ervice Bus (ESB)
An ESB provides an implementation backbone for a SOA that treats appli-
cations as services. The ESB is about configuring applications rather than
coding and hardwiring applications together. It is a lightweight infrastruc-
ture that provides plug-and-play enterprise functionality. It is ultimately
responsible for the proper control, flow, and even translations of all mes-
sages between services, using any number of possible messaging protocols.
An ESB pulls together applications and discrete integration components to
create assemblies of services to form composite business processes, which in
turn automate business functions in an enterprise. It establishes proper con-
trol of messaging as well as applying the needs of security, policy, reliability,
and accounting, in an SOA architecture. With an ESB SOA implementation,
previously isolated ERP, CRM, supply chain management, and financial and
other legacy systems can become SOA enabled and integrated more effec-
tively than when relying on custom, point-to-point coding or proprietary
EAI technology. The end result is that with an ESB, it is then easier to create
new composite applications that use pieces of application logic and/or data
that reside in existing systems.
9.1 Defining Enterprise Service Bus (ESB)
The Enterprise Service Bus (ESB) is an open standard-based message back-
bone designed to enable the implementation, deployment, and management
of SOA-based solutions with a focus on assembling, deploying, and manag-
ing distributed service-oriented architecture (SOAs). An ESB is a set of infra-
structure capabilities implemented by middleware technology that enable
an SOA and alleviate disparity problems between applications running on
heterogeneous platforms and using diverse data formats. The ESB supports
service invocations, message, and event-based interactions with appropriate
service levels and manageability. The ESB is designed to provide interop-
erability between larger-grained applications and other components via
standard-based adapters and interfaces. The bus functions as both transport
and transformation facilitator to allow distribution of these services over dis-
parate systems and computing environments.
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