Dynamips
Dynamips is software to emulate Cisco hardware on a conventional PC. It is important here that Dynamips does not emulate the entire router, but only the hardware (analogous to VMware for conventional PCs). This means that a suitable IOS is required to be able to use Dynamips.
Functionality
Dynamips was originally intended as an emulator for a 7200 router, but now emulates the following devices:
- Cisco 7200
- Cisco 3600 Series (3620, 3640, 3660)
- Cisco 3700 Series (3725, 3745)
- Cisco 2600 Series (2610 through 2650XM, 2691)
In addition, Dynamips offers the option of equipping the virtual devices with additional plug-in modules (NPE-400, PA-8T, NM-4E, NM-16ESW, NM-1FE-TX to name just a few) according to their available slots.
A large number of IOS versions are supported, up to 12.2S and 12.4T.
Since there is no console connection to manage a virtual router, the CLI can be operated via Telnet on the host computer.
The interfaces of the virtual router can be linked to real network interfaces. This creates the possibility of connecting real hosts via virtual router networks.
More software
In order to reduce the complexity of using Dynamips , Dynagen was created as a text-based front end for Dynamips. To use Dynagen, Dynamips must be started in the so-called hypervisor mode . It then manages several routers at the same time with one instance.
Dynagen makes it possible to create complex router networks with the help of very simple configuration files. A simple example could look like this:
[localhost:7201]
[[7200]]
image = c7200-jk9o3s-mz.124-7a.image.bin
npe = npe-400
ram = 160
[[router R1]]
model = 7200
slot1 = NM-4E
[[router R2]]
model = 7200
slot1 = NM-4E
e0/1 = R1 e0/1
In this example, a model 7200 is defined on the local Dynamips server (which here runs differently from the default port 7200 on port 7201) with details of the image file, the NPE-400 expansion module to be used and 160MB of RAM memory, of which two instances R1 and R2 can each be created with a 4-port Ethernet module NM-4E. The interface Ethernet0 / 1 of router R2 is connected to Ethernet0 / 1 of R1. It is sufficient to define this connection on one of the two terminals. By default, the created devices can be reached on the host computer via Telnet in the specified order starting at port 2000. In this case R1 on port 2000, R2 on port 2001.
The configuration file also allows you to create simple switches that can be used to connect multiple interfaces together.
GNS-3 was developed as a graphical user interface for Dynamips and Dynagen. GNS-3 allows a complex configuration of the virtual environment by means of a simple graphical interface.
Web links
- www.ipflow.utc.fr Wiki page of the developer of Dynamips
- 7200emu.hacki.at Very good internet forum on Dynamips and everything that goes with it
- www.dynagen.org Homepage of the Dynagen developers with download, tutorial, the GUI GNS-3 and more
- www.gns3.net Website of GNS-3