You can select Preferences under the Edit menu and check the appropriate boxes to enable these features.
As mentioned above, GNS3 is not just a simulator, it is also an emulator. It can emulate a long list of router platforms and other devices. Additionally, if you use an EtherSwitch card in a router, switching platforms can also be emulated depending upon the degree of the card’s supported functionality.
It uses a TCP/IP communications channel for the Dynamips hypervisor mode, which means you can run GNS3 on one machine and the Dynamips emulator on a different machine. So, GNS3 provides you the flexibility of working with a remote host machine, if required.
Another key feature of this tool is that you can use it to connect your virtual devices with real network hardware. Although the provided switching environment is limited for networking personnel who want to make more advanced switching labs, it is good enough for the people who want to study for their networking certifications.
GNS3 as a learning tool
GNS3 can emulate most of the router platforms and other network devices. You can use GNS3 as an alternative or complementary tool to real labs and simulate Cisco and Juniper topologies.
Also, the VirtualBox support in GNS3 allows even system administrators and engineers to utilise GNS3 to make labs and test network features.
Additionally, the high level of accuracy in simulations makes GNS3 a suitable choice to experiment with features or to check configurations that need to be deployed later on real devices. For example, you can connect your virtual network to real ones or capture packets using Wireshark to start with your experimentations.
The key feature which sets GNS3 apart from the other router simulators in market is that you can actually work on the same operating systems as in real networks and simulate them with higher accuracy in virtual environment.
There are several other router simulators in the market, but with the downside of being limited to the command line that a developer can choose to include. Also, these are not always accurate as the real network.
Most likely, you will find some commands or parameters which are not supported when working on a practice lab. Moreover, the other simulators can only provide a representation of the output of a simulated router where the accuracy of such representations depends only on the developer. But with GNS3, which allows you to run an actual Cisco IOS, you can see the exact output the IOS produces and have access to any command or parameter supported by the Cisco IOS.
Additionally, GNS3 is an open source, free program for you to use. However, licencing restrictions require you to provide your own Cisco IOSs to use with GNS3. Also, throughput provided in a virtual environment by GNS3 is around 1000 packets per second while a normal router will provide a hundred to a thousand times greater throughput.
We do not say GNS3 can take the place of a real router, but it is a tool for creating a lab environment which can provide you a good learning and testing closest to the real ones.
To download the latest versions and support, visit the official website www.gns3.net. Official documentation and video tutorials are available at the website for your help. For any technical support, you can contact GNS3 community forum and social media sites. Also, a collection of exercises/labs to learn more with GNS3 is available at the website.
An IRC channel is also available on Freenode dedicated servers, which can be accessed via irc://irc.freenode.net:6667/gns3. You can talk about anything concerning GNS3—future releases, new features and ideas on this channel.
Now you can experiment with configuring virtual networks on a PC or a Raspberry Pi running Linux, and simulate in the closest possible way to how the real networks perform.
The author is a technical journalist at EFY