deploying and managing ip over wdm networks - Index of

Management System Design and Implementation Issues 157
Figure 8.11 Sample of an integrated connection request dialogue.
WINMAN components in order for the GUI client to be as thin, independent,
and modular as possible. As a design principle, it has been decided that the data
retrieval by the GUI is accomplished in pull mode. Therefore, the view manager
provides an interface to the GUI, but not vice versa, because in general the GUI
can be mounted anywhere in a distributed environment. The rest of the components
do not need to be aware of its existence and exact location. In order for the
GUI client to obtain information, it uses the methods specified by the interface
provided by the view manager. To avoid drawing enormous amounts of data in
one call (which reduces the performance of the system), iteration methods have
been introduced that fragment the large bulk of data into smaller pieces and
facilitate unhindered communication.
The object model adopted by the GUI follows a flat structure; that is, for
reasons of scalability, a single class: the WinmanObject class, abstracts all of the
particular entities that lie in the inventory. The task of translating the nested
hierarchical structure of the system to the swallow model of the GUI level is
taken on by the view manager server. The WinmanObject class is outlined in
Figure 8.12.
Besides its interaction with the view manager, it was intended that the
GUI act as a receiver of certain notifications that are related to changes in the
status of connections (e.g., it should be notified whenever one connection is created
or removed). In such a manner, the GUI depicts in real time an exact picture
of the underlying network.