Accurate reproduction of a WAN in a simulation to study the effect of changes
Sector
Chemicals Industry
Project details
The project’s objective was to reproduce an accurate image of an international corporate network with more than 30.000 IP devices in a simulation model, in which subsequently the effect of network changes (e.g. link upgrades, link failure or migration of servers) can be tested. The network simulation has to include all the WAN connections of the network and the Access Routers. The internal networks of each corporate site should be considered as a whole, i.e. not for each separate device. The basic network load data for the unmodified network should be retrieved from the operational network and individual applications should be simulated based on charted transaction data. The objective of the simulation was the evaluation of the WAN properties (Link Load, Latency, Packet Loss Rate) as well as the duration of transactions between different corporate sites after the changes.
The tasks in detail:
- Automatic retrieval of the router configuration
- Generation of a network topology model from the configurations
- Automatic retrieval of Load- and Flow-Information from different Monitoring Systems
- Parameterization of the Simulation Model using Load data from the operational system
- Operational measurement of Application transactions and integration into the simulation
- Simulation of the network performance
- Simulation results collection and automatic generation of reports
After an in-depth analysis of the requirements and the operational technologies the qualified Simulation and Application testing tools were selected. Through a series of self-developed programs the retrieval of router configurations and load data from the operational system was automated. That way, an update of the model can take place anytime with minimal expense. The router configurations and load data were imported into the simulation in order to generate the network model and transformed according to each scenario in order to investigate the different questions, i.e. connection parameters were modified, the server sites moved and new applications were rolled out in the simulated network. The simulation results were summarized in several reports and put in the disposal of the network officers or the application developers as a decision basis. Furthermore, the connection properties acquired in the simulated network were used for the emulation of WAN-links during the Pre-Rollout-Test of newly developed applications.
Time frame and T&M
The preliminary enquiry and the tool selection took place with an expense of 10 man-days within a one month period. The implementation was carried out with an expense of 60 man-days within a period of 6 months.
Deployed Technologies
- Opnet ITGuru/ACE for Simulation and Application operational testing
- Perl for the automation of router and load data querying
- Concord eHealth, IPanema, InfoVista as data sources of the WAN-Monitoring
- Linux and NistNet for the WAN-Emulation
Result
The project was implemented successfully within the time and budget frames. The choice of the optimal tools for this use case was essential to the project’s success. Especially the involvement of several external data sources presented a great challenge, which could be automated using scripts specific to the customer. That way an update of the extensive network model is possible within a few hours. A valuable side-effect of the update process is that it points out a broad spectrum of inconsistencies and errors in configuration. Beyond the planning objective the implemented solution also facilitates the support of network problems troubleshooting as well as the documentation of the corporate network evolution.
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