Tag Archives: virl

Cisco VIRL Network Simulation Features

If you haven’t checked out all the features available through VIRL, take a look at this features page located on the VIRL website…you can scroll down to the bottom, and under “All Features” click the “OPEN ALL” button.  As you can see VIRL is a feature rich environment. One note of interest is the expected release of an updated Nexus switch object later this year…looks like it might include a number of layer 2 features, perhaps even vPC!!

Cisco VIRL Features


Nexus Switches – Time to do Some Serious Learning!

I have yet to work with the Cisco Nexus line of switches…just never had the opportunity. I’ve worked a lot over the years with Cisco’s chassis class line of switches (5500’s and 6500’s), and a bunch of their stackable switches (3600’s and 3700’s). So, all of a sudden, I need to learn about Cisco’s 9000 line of Nexus switches…and fast. What to do??

Read…a lot. I spent a fair amount of time this weekend just reading up on a bunch of technical papers from Cisco. Here is a great starting point…scroll down to see a large variety of topics pertaining to the 9000 series…

Cisco Nexus 9000 Line of Switches

The next thing I did was setup a small two-tier Nexus network simulation within VIRL.  This is very cool…I am able to check out configurations, learn the NX-OS syntax, and just have some fun playing with the Nexus switches. Topology was straight forward, and I have BGP and OSPF in the mix…(AutoNetkit is your friend)…

Simple Nexus switch simulation running in Cisco VIRL

Simple Nexus switch simulation running in Cisco VIRL

Now, running a Nexus simulation within VIRL is not perfect…there are still some features that don’t work, such as vPC (Virtual Port-Channel), but it is a good start. And it is sure helping me out a lot.

Note:  There is a bug in the NX-OSv VIRL node that ends up creating all of the switch interfaces with the same MAC address (0000.0000.002f).  Obviously, nothing works if this is the case. The VIRL team is working on this, but there is a work-around…simply use AutoNetkit to create the switch configs, and each interface will have proper MAC addresses created. If you would rather do most of the configuration yourself, then still use AutoNetkit but choose the “Infrastructure Only” option…you will end up with a minimal starting configuration, but with working MAC addresses. AND…remember to click the “Build Initial Configurations” button before you start the simulation!!


Cisco VIRL – 20 Node IOSv Test

Greetings!! So I’ve been playing with the latest Cisco VIRL release (v1.0.0), and let me say for the record, I like it!! Of course I’m still relatively new at VIRL and have much to learn, but I am very impressed by the latest release. AND I’m very pleased with the new bare-metal VIRL installation I have!

If you recall, several months ago, I installed VIRL on my new desktop system (Quad core i7 processor, 32 GB of RAM, fast SSD and storage drives, Windows 8.1 and VMware Workstation 11). VIRL ran very well on that system, which is to be expected, but there were times when my PC just behaved a bit strangely…a bit of pausing, some hiccups…you know what I mean. Of course I was running other power hungry programs at the same time…Photoshop and Lightroom. This installation is a bit more complex…you have a physical PC, running Windows 8.1 for an operating system, running VMware 11, which runs a VM (Virtual Machine), which is running Linux, which then runs it’s own VM that runs the network simulation (routers, switches, etc). Whew…it’s complicated just typing all of that out!

So…I decided to upgrade my Dell 2950 PowerEdge server a bit. I added RAM and another processor, so it now has:  dual Quad-core Zeon processors (3 Ghz); 16 GB RAM; and fast 15K RPM drives. Let me tell you…this thing screams. Yes, it has less RAM than my PC, but now it will be dedicated to just Linux and the network simulation…nothing else. The new setup is much simpler now…a physical server, running Linux, which runs a VM for the network simulation.

How does it work? NICE!! I setup a test 20 node router simulation and cranked it up…it took about 2.5 minutes for all nodes to go ACTIVE, and another 1.5 minutes for BGP and OSPF convergence to complete. Here’s the topology for the test…

20 Node VIRL Simulation

20 Node VIRL Simulation

And here are the resources used…

Resources used for 20 node test

Resources used for 20 node test

Everything is looking very good here. Of course, I am using just IOSv nodes (routers)…they are the least CPU and RAM intensive. If I were using other node types (NX-OSv, ASAv, CSR1000v, etc) then I would be running out of resources sooner and would have to balance the number and type of nodes I could run in a simulation. What will help is to upgrade my RAM to 32 GB, which I will do early next year.

Do you like what you see? Then take a look at VIRL…I think you will be very pleased.