416 Chapter 12: Testing Your Network Design
Predicting end-to-end performance prior to deploying new applications or
technologies
Developing service-level agreements (SLAs) based on verifiable performance
predictions
Monitoring actual performance and comparing it with expectations or SLAs
NetPredictor lets you model an existing network and then simulate replacing existing
devices with other network components to determine how performance will change. The
model can be based on knowledge about the network and applications that you provide, and
information from a device library. The model automatically adapts to data that NetPredictor
captures from the actual network.
Model-adaptation approaches have been used extensively in many other industries (for
example, the chemical-processing and aerospace industries). NetPredictor is the first
product based on a model-adaptation approach for network management. The following
example demonstrates how NetPredictor was used in an actual network design and testing
scenario.
An Example of a Network Design Testing Scenario
This section discusses a network design and testing project that was completed for Umqua
Systems, Inc., using some of the design steps described in this book and chapter. The
example is based on a real network, but the name of the company has been changed, and
some facts have been obscured to protect the company’s privacy. This particular company
still had some old technology, such as FDDI. Don’t be thrown off by this. The testing
methods described in this section can apply to networks with any type of technology,
whether it’s old or new.
Background Information for the Design and Testing Project at
Umqua Systems, Inc.
Umqua Systems designs and manufactures specialized integrated circuits for the consumer
electronics and digital-office markets. The design project for Umqua focused on the campus
network that connects 3 buildings in close range to each other and one building about
3 miles away. The campus network interconnects approximately 400 engineering, sales,
marketing, and finance employees.
Goals for the Design and Testing Project
Umqua had two main goals for the design and testing project:
Determine the load and performance of the current network, with a focus on the FDDI
backbone.

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