Capacity planning with NNM
Using NNM, you can do some planning to determine the impact of new requirements on your network. This tip, excerpted from OpenView Network Node Manager, by John Blommers, published by Prentice Hall PTR, discusses some basic ideas for how to do it.
NNM provides the as-built network topology for capacity planning. HP NetMetrix can provide the existing performance metrics. HP Service Simulator can import both topology and performance data to create a baseline simulation model of your network. What's next, then?
Before you can use the simulator and write a capacity plan, you must have a question to answer. The kinds of questions you might consider are as follows:
- Can the network handle another 1000 users?
- What happens when I consolidate 100 mail hubs into 10?
- What upgrades are needed to support our new ERP application?
- Will adding a second T-1 line meet response time requirements?
- Can the network handle the new print-on-demand technology?
All of these are what-if questions. You typically take the baseline simulation model created with the Service Simulator, make changes postulated in the question, and let the simulator calculate the impact on response time and circuit utilization.
If you are planning to add a new application to the network, you need data about its traffic requirements. You also need LAN analyzer traces of the most commonly used transactions. These can be imported into the simulator. Edit the network topology, move servers around, add new clients and servers, modify line speeds, and run the simulator to see what happens.
Do any circuits operate at capacity? Are transaction response times within acceptable limits? If not, then change some parameters and try again.
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This was first published in August 2001