Network simulation or emulation? | Network world


As a network engineer, a misconfigured application can cost a lot of time and money down the line. The best way to try and prevent these unfortunate accidents is to perform thorough and effective testing on a regular basis. Whether it’s designing a network, migrating to the cloud, or adding a new device to the rack, every step of the application deployment lifecycle must be validated through precise testing.

With regard to network testing, the terms emulation and simulation are often used interchangeably. In most cases, either term will usually get the message across, but there is a big difference between a network emulator and a network simulator, both practically and semantically.

A simulator can perform tasks in abstract To to prove the behviour network and its components, while an emulator can copy the behavior of a network for functionally replace this.

Network simulators

At a basic level, a network simulator uses mathematical formulas to create a theoretical and fully virtual model of a network. Simulators are software solutions and different types are available for different applications. Although used primarily for research and educational purposes, they can also serve as crucial testing tools in network design and development.

Simulators, such as ns-3, are used to simulate networking and routing protocols. OPNET, which was acquired by Riverbed in 2012 and applied to their Central Steel product line, also provided a stand-alone simulation environment.

These two network simulators use simulation of discrete events which queues and chronologically processes events such as data flow. This allows a network architect or engineer to build and evaluate an experimental model of a network, including its topology and application flow. Since a variety of theoretical scenarios can be introduced into a network where anything can be built and applied, performance can be hypothetical even before the network itself has been implemented in the real world.

While testing a network in this way can save time and money, network simulators are not without limits. These very complex operations require a certain level of experience and training to be properly configured in order to obtain reliable results. In addition, network simulators are simply not practical as some events cannot be anticipated independently of a physical network.

Network emulators

A network emulator, also called WAN emulator, is used to test the performance of a real network. These devices can also be used for purposes such as quality assurance, proof of concept, or troubleshooting. Available as either hardware or software solutions, a network emulator allows network architects, engineers, and developers to accurately assess an application’s responsiveness, throughput, and quality of the end-user experience before they start. ” apply changes or additions to a system.

By physically placing it between two LAN segments, a network emulator can accurately replicate a client / server WAN connection without the need for a router, modem, or even live traffic. It can then be configured to manipulate bandwidth constraints and apply impairments, such as packet loss, delay, and jitter, to the mirrored network. Latency can be specified to emulate data transfer over long distances, and applications behave and respond as if they are physically separate. Application performance and the end user experience can then be observed, tested and validated under such conditions in real time.

Software solutions, such as NetEm, which are prepackaged in the Linux kernel, are ideal for testing at low data rates, but are limited by the test machines on which they run.

Hardware solutions, such as Linktropy 8510 by Apposite Technologies (Disclaimer: I am currently working for Apposite Technologies), are specially designed devices. The test can be completed in minutes by simply installing the device online between the client and the server and configuring the traffic settings. A hardware WAN emulator can emulate thousands of high-speed client connections, but they’re not free.

You say potato, I say tomato

Understand the difference between a network simulator and one network emulator will expand your test toolkit and optimize your engineering efforts. Both are useful and necessary tools and each have their own purpose. A network simulator will help you design a network from scratch without the need for physical devices. Are you looking to develop a satellite communication network from scratch? Use a network simulator. Once that network is designed and built, a network emulator will help you test and validate application performance, troubleshoot, and provide proof of concept. Thinking of switching from MPLS to SD-WAN? Be sure to use a WAN emulator to validate and test the considered vendors and appliance to ensure they can meet the performance requirements of your current system. Good luck.

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Copyright © 2017 IDG Communications, Inc.

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