Top-Down Network Design, Second Edition

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.