This means that a scaled out database can look like a single
large database to an application. Similar to this, ESB can be seen as a means to
link services. Binding to remote end points is synonymous to linking to remote
databases??”an application code can interact with the linked services as if they were
local to the invoking code.
Chapter 1
[ 29 ]
Virtualization of Services
By service virtualization, I mean dividing the organization's information assets into
"Virtual Services" without regard to the transport or binding protocol of the actual
implementation components. Corporate network assets (information) can reside
in multiple places like in a centralized mainframe or distributed across multiple
systems implemented using DCOM, RMI, IIOP, remoting, or SOAP protocols.
Service wrapping and service aggregation are two methods by which we can
virtualize them to be exposed in a consistent way to external or internal clients.
Thus, virtualization is closely related to "black box" reuse of services by providing a
different interface at the same abstraction-level. The ESB abstracts behind the scene
addressing, translations, and aggregation.
Pages:
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65