CIS460 – NETWORK ANALYSIS AND DESIGN

CHAPTER 11

Testing Your Network Design

Introduction

• This chapter covers using industry tests to predict network performance

• It also covers building and testing a prototype system and using network-management and modeling tools to anticipate the end-to-end performance and QoS

Using Industry Tests

• Many sources of test results– independent labs– trade journals– vendors

• Simple network designs can relay on these tests

• Most tests are component tests vice system

Building and Testing a Prototype Network System

• An initial implementation of a new systems

• provides a model on which the final implementation is patterned

• validate operation and performance of new system

• functional but not full-scale

Determining the Scope of a Prototype System

• Depends on both technical and non-technical goals

• ability to implement depends on resources available

• Three ways– As a test network in a lab– Integrated into a production network off-hours– Integrated into a production network normal hours

Determining the Scope of a Prototype System (Cont’d)

• Remember– warn users in advance– Warn network administrators and other

designers - other tests– Warn network managers - alarms/traffic– run multiple short tests– start with small change– monitor test results and discontinue

Writing a Test Plan for the Prototype System

• Test objectives and acceptance criteria

• types of tests that will be run

• Network equipment and other resources required

• Testing scripts

• Timeline and milestones for testing project

Developing Test Objectives and Acceptance Criteria

• Objectives should be specific and concrete– Response time of application– Throughput of application

• Based on business and technical goals

• Avoid incorporating biases or preconceived notions

• Based on baseline measurement for current system

Determining the Types of Tests to Run

– Performance - level of service in throughput, delay, delay variation, response time and efficiency

– Stress - degradation of service due to increased offered load

– Failure analysis - network availability and accuracy, causes of any network outages

– Other tests might include manageability, usability, adaptability and security

Determining the Types of Tests to Run (Cont’d)

• Application response time testing

• Throughput testing

• Availability testing

• Regression testing

Documenting the Network Equipment and Other Resources

• Test plan should include a network topology drawing and a list of devices that will be required

• Other resources including:– lab time– help for co-workers or staff– Help from users– Network addresses and names

Writing Test Scripts

• Write a script of how the test will be run. Include– Test objectives– Acceptance criterion– Test steps

Documenting the Project Timeline

• For complex testing projects the test plan should document the project timeline, including start and finish dates for the project and major milestones

Implementing the Test Plan

• Follow the test scripts

• Document your work

• Keep a daily activity log

Tool for Testing a Network Design

• Network-management and monitoring tools - used in a production environment to alert network managers to problems and significant network events.

• Modeling and simulation tools - develop modal of network

• QoS and service level management tools- analyze end-to end performance for network applications

Specific Tools for Testing a Network Design

– CiscoWorks Blue Internetwork Performance Monitor– Cisco’s Netsys Tools– Cisco StrataSphere Modeling and Optimization Tools– WANDL’s Network-Planning and Analysis Tools– CACI Products– Make Systems NetMaker XA– NetPredict’s NetPredictor