Dynamips emulator download

I plan on several more posts about Dynamips and Cisco cert prep; this one's just to get use started. I've also got some handy links listed at the bottom of the page. The Dynamips software acts like Cisco router hardware several supported models and interface cards.

Then, the user you and me supplies a copy of the real IOS software that would normally run on real Cisco router hardware of that same model. The IOS software has no awareness that it is executing on an emulator. Dynamips supports multiple emulated routers, the use of emulated serial and Ethernet links, and even the ability to communicate outside the computer running Dynamips through the computer's physical Ethernet interface. Dynamips intercepts calls to the router hardware.

If two images were configured to be connected via a point-to-point serial link, Frame Relay PVC, or Ethernet, Dynamips would receive the IOS call to forward the packet, and then deliver that packet to the router on the other end of the link. Packet per second performance is constrained a bit, but allowing the actual passage of packets allows things like ping commands, traceroute commands, routing protocols, CDP, and the like to work just like they would on real hardware.

However, you can communicate between the emulated routers, out the PC's Ethernet card, to a real Cisco switch and any other devices on the switch, like your PC. To net it out: you can run multiple routers using Dynamips with your PC.

You can build any router topology you like. And Dynamips is free! Dynamips is the emulator, but you'll use two other pieces with it.

When I'm listing "Dynamips", I'm using the term loosely, meaning everything you'd need to download to use it. Only the c series get newer IOS 15 images. All other platforms are now end-of-life and only support IOS You will find the technology train images to contain the newest features but it may also contain the most bugs. We recommend Mainline over Technology train if you are interested on stability without the need of new features. The minimum RAM is the amount of memory needed for IOS to work at maximum capacity with most feature configured and activated.

From experience you can usually use a bit less RAM just fine. Idle-PC values are not required with virtual machines or docker containers. Note that interfaces do not use a slot designation e.

File name: cadventerprisek9-mz. IOS version The c supports up to 2 Network Modules maximum of 8 Ethernet ports, 32 FastEthernet ports or 8 serial ports.

File name: ca3jk8s-mz. The c supports up to 4 Network Modules maximum of 16 Ethernet ports, 32 FastEthernet ports or 16 serial ports. If this host interface is connected to a real switch that is configured for trunking, you can now easily connect any router instance to any VLAN you wish.

As of Dynamips 0. Working with these models of routers is much like working with s. You can specify default options that apply to all , , , , , or s in your lab with [[]], [[]], [[]], [[]], [[]], and [[]] sections. When defining routers, the default is to emulate a You can mix and match router models in the same lab. Refer to the Dynamips web site for an up to date list of which network modules are supported.

First we specify the devices to run the local system a Windows XP host :. A windows server the local machine. This is because the other server defined below will use this name when talking to our local system. Second, connecting to a device on another system is as simple as specifying it the same way you would if it was on the local system.

Next we define the other Dynamips server, and the router instance running on it:. A linux server. We are specifying the TCP port that the Dynamips process is listening on as But if you set up Dynamips to listen on a different port you would specify it here. When talking to a remote server, you need to specify the working directory for this lab.

As you may have noticed in the previous labs, Dynamips stores several files in the working directory. These include the NVRAM for the virtual router, as well as the bootflash, logfiles, and some other working files. When running Dynamips and Dynagen on the same machine, you do not need to specify the working directory, because Dynagen defaults to using the same directory as the network file. But in a distributed setup the network file is on the client and the working files are on the host.

So specify the fully qualified path to the working directory on the Dynamips host. Be sure to use the correct directory separation character for the platform here forward slashes for a Linux system. This includes the Dynamips server port defaults to TCP , the console ports e. As described in the Resource Utilization section your labs can consume a large amount of real and virtual memory.

The Ghostios option can significantly reduce the amount of real host RAM needed for labs with multiple routers running the same IOS image. With this feature, instead of each virtual router storing an identical copy of IOS in its virtual RAM the host will allocate one shared region of memory that they will all utilize. This option can be used in several places:.

Dynagen is smart enough only to use ghostios if there is more than one router using the same IOS image. The other files typically created with a router instance are created as well log, nvram, and possibly bootflash files. Measuring the amount of host memory saved with ghostios can be a little tricky due to the complexities of memory management in modern OSs.

For example, on Windows, after the VM space used by cygwin and other libraries dynamips depends on, this only leaves room for 4 router instances MB each! Enabling sparsemem only allocates virtual memory on the host that is actually used by IOS in that router instance, rather than the entire amount of RAM configured.

This can allow you to run more instances per dynamips process before you have to resort to running multiple dynamips processes.

See this FAQ item for more info on this issue. Neither ghostios nor sparemem are enabled by default, so you must turn them on with:.

If you use ghostios, the shared memory will be memory-mapped no matter what your mmap setting is. If you enable sparse-mem, no memory mapping will occur for router memory.

You can choose to use ghostios or sparsemem separately or together. Here is an example network file with typical ghostios and sparsemem usage — configured at the top level so that they are applied to all router instances in the lab:.

The network file would look something like this:. To view the traffic in real-time, open the file with Wireshark. The capture is continuing to write packets to the output file. In this case we must also specify the encapsulation we are using on our routers, so Wireshark will know how to decode the packets.

To capture some traffic on our HDLC encapluated r2 to r3 link use:. Now we can open r2. Note that you can have multiple captures running simultaneously against different interfaces on different routers. Dynamips and Dynagen provide more options and interface types than shown in this tutorial. Here are some additional commands that can be used in the Dynagen management console that are not explained in this tutorial. Introduction Dynamips is a Cisco router emulator written by Christophe Fillot.

Dynagen simplifies building and working with virtual networks: Uses a simple, easy to understand configuration file for specifying virtual router hardware configurations Simple syntax for interconnecting routers, bridges, frame-relay and ATM, and Ethernet switches.

Dynagen can also control multiple Dynamips servers simultaneously for distributing large virtual networks across several machines. Or you can run Dynamips and Dyngen on the same system Provides a management CLI for listing devices, starting, stopping, reloading, suspending, resuming, and connecting to the consoles of virtual routers. Installing Dynagen runs on any platform that supports Python, which is to say nearly any platform.

Configuring your Telnet Client Dynagen includes a console command that allows you to connect to the virtual router consoles directly from the CLI. Simple lab Any line prefaced with a is a comment, and is ignored [localhost] The first section specifies the host that is running Dynamips. No need to specify an adapter here, it is taken care of by the interface specification under Router R1 Although we have to create the R2 router, we do not need to specify any adapters here.

Running Simple Lab 1 In order to run this virtual lab, first start up the Dynamips server on your local machine. Working with the Management Console From the Management Console, use the help command to see a list of valid commands: To get help on a particular command, either type help command or command?. First, open a lab and make sure only one router instance is running stop any others in the lab if need be : Then, telnet to the running router instance.

Otherwise, do not press anything: Wait for all the interfaces to initialize, then wait a bit to ensure that the router is no longer booting and is idle. You will see a message that statistics are being gathered, and about 10 seconds later you should see a list of potential idlepc values: Values that will most likely provide better results are marked with an asterisk.

Frame Relay Lab Dynamips and accordingly Dynagen provides support for an integrated frame relay switch. Launching the lab shows the following: Several things to note here. Communicating with Real Networks Dynamips can bridge virtual router interfaces real host interfaces, allowing your virtual network to communicate with the real world.

Ethernet Switch Lab New to Dynamips as of version 0. Memory Usage Optimizations As described in the Resource Utilization section your labs can consume a large amount of real and virtual memory. This option can be used in several places: If used at the top level, ghostios is applied to all router instances in the lab If used at the defaults section e.