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by Niccolo' Cascarano last modified Nov 30, 2010 10:57 PM

Download Dyn@NG

You can download Dyn@NG software here: dynng.tar.bz2 (version 0.3.1 - last update 30/11/2010)

Please refer to the README file for information about installation and configuration.

Why Dyn@NG?

Dyn@NG is born with didactic purposes. Before Dyn@NG, we had several Cisco routers in a lab, and we created a system that allowed student to access to it from remote. While reasonably flexible because of the possibility to practice with real network devices without being physically in the lab, there were still many limitations, particularly because of the limited amount of routers we had and the problems due to the remote lab maintenance (resetting devices when some trouble appears, changing the topology, etc).

In order to address those limitations we decided to move to a virtual lab and we chose GNS3. This tool enable us to configure potentially any topology with an arbitrary number of Cisco devices. GNS3 uses Dynamips for emulating a Cisco device, running the real Cisco IOS. With GNS3 you can easily configure the network topology you want, then GNS3 will spawn the proper number of Dynamips instances (one instance per router) for emulating the routers and allow you to connect to the console ports of the routers in order to configure the devices.

However, Dynamips requires quite a huge amount of resources (in particular, CPU) and often students cannot run complex topologies on their laptops. However, GNS3 can connect also to a remote instance of Dynamips and run the emulation on a different machine.

So GNS3 and Dynamips seemed to us the perfect candidates for substituting our real laboratory with a virtual one, since we can run the graphical frontend (GNS3) on student's laptops, and setup a very powerful machine in the backend where Dynamips is launched.

Given the above setup, GNS3 and Dynamips represent the perfect candidates for substituting our real laboratory with a virtual one.

However, some issues are still there:

  • GNS3 cannot administer multiple instances of Dynamips, while we want several students to complete their lab at the same time
  • Users must have a Cisco IOS image (students cannot buy a Cisco image, which does not come for free)
  • If you run Dynamips on a remote machine, you must have access to that machine for retrieving capture files
  • The GNS3 configuration for using a remote Dynamips is not trivial, especially if you want to run more instances for different users

Dyn@NG is a tool that aims at solving the above issues, facilitating the user interaction with a remote Dynamips and allowing a seamless implementation of a virtual Cisco lab.

Dynamips @ Netgroup virtual laboratory interface (in short Dyn@NG) is a Web Interface for enabling users to spawn a dedicated remote Dynamips hypervisor without granting them access to the host machine.
Dyn@NG also creates the actual GNS3 project files starting from template files and populating them with ad-hoc configuration for each user. This step is required since each remote user must refer to a specific Dynamips instance, which is characterized by some peculiar  parameters (i.e., a specific TCP/UDP port, a particular path on disk for temporary files, etc). 

Dyn@NG also provide a very simple administrative interface for monitoring the CPU load history on the machine running Dyn@NG and the users' hypervisor instances.

The user interface

The user interface perform mainly three operations:

  • launch and keep alive the remote dynamips instance
    • (make sure that Javascript is enabled in your browser, otherwise dynamips will not start)
  • provide ad-hoc GNS3 project files for each user
  • show a live preview of the traffic captured on all the network links

Since the load imposed by dynamips instances could be rather high, the user interface shows also the current server load.

If a user wants to create it own topology but still on the remote Dynamips instance, the user interface also returns all the essential parameters that the user need to set into is GNS3 client.


Here is a screenshot of the user interface:






The monitoring interface

The monitoring interface can be accessed by the administrator user. It gives a very simple report of the server disk and CPU usage.

This can be useful to monitor the health of the server running the Dynamips instances.

Here is a screenshot of the monitor interface:





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