One of the known issue for anyone preparing for a Cisco exam is that the solutions available today don’t support all the needed features. Cisco VIRL supports L2 switching out of the box, whereas GNS3 does not. GNS3 supports the configuration of serial interfaces on routers whereas Cisco VIRL does not. For someone starting out in this field it can be enough to discourage them. Fortunately there is a way to bridge the two together and it’s not difficult to do at all. While I present one method here, please note that there are other ways to do this as well.
Here’s how I do it with my Macbook Pro running VMware Fusion Pro, a VIRL VM, and a Windows 10 VM.
Create a simple topology in VM Maestro
Once you have a topology you’re happy with set the flat network to use the flat1 network, which is on vmnet2 in this case.
Next generate the ANK configuration.
Start the simulation and check the IP address on the G0/1 interface.
Now head over to our Windows VM which is also on vmnet2. Set the IP address to something on the same subnet. This isn’t entirely necessary but the Windows VM is not need Internet connectivity.
Ping the router running in VIRL.
With a successful ping you can now configure GNS3. Create a topology in GNS3 with a router and a cloud. Add the serial interfaces as desired. Start the topology.
The key here is making sure that the cloud is bridged to the eth0 network.
After you boot the topology give the interface an IP that’s on the same subnet as the VIRL router.
Now ping the VIRL router.
From here on out you can build out the serial side of things as you wish. Connect the two networks with an OSPF or BGP peering.
This simple bridge between GNS3 and VIRL demonstrates the power we have in VIRL and GNS3 and how they can have a sort of symbiotic relationship. GNS3 has a lot of nice integration and tends to be a bit more user-friendly. But on the other hand, Cisco’s VIRL is a solid product that’s catching up in functionality. As it stands today, you probably would do well to run both. I don’t think you can rely solely on just one for certification studies. Each of them also have their strengths and weaknesses alike.
Another interesting point to make here is that people in the past have been concerned about running GNS3 since it’s not a Cisco product. Of note to me is how VIRL, an official Cisco product, provides the ability to import GNS3 topology files. Perhaps down the road the integration will tighten up and we can have a single solution for creating and testing complex topologies. For now a simple bridge between VM’s will do and we can at least lab most topics of the CCENT and the CCNA in this manner.