VIRL vs GNS3 vs Packet Tracer which one

Network simulators are a great resources for mocking up certain scenarios, learning, certifications, and plain old “what will happen if I do this in my network” testing.  There are are a variety of simulators available out in the wild for use, however, the three main ones that I like to use for different reasons are VIRL, GNS3, and Packet Tracer.  Which one of these however is best to use?  Well, unfortunately, I don’t think there is a clear cut answer to that question as I think each one has certain strengths they bring to the table.  Let’s take a look at VIRL vs GNS3 vs Packet Tracer which one?

VIRL vs GNS3 vs Packet Tracer which one

The first simulator we want to take a look at is Cisco’s VIRL.  There is no doubt about it, Cisco is putting a lot of weight behind the VIRL product as being its preferred testing and simulation software moving forward.  VIRL certainly has a tremendous amount of features and capabilities.  Also, it touts some of the newest IOS versions, routers, and appliances that you can get your hands on.  Including some that you may have a hard time getting your hands on otherwise such as the high end Nexus line products.

VIRL is a beast when it comes to resources and complexity.  I have it loaded in VMware’s Workstation product and have it running on a healthy Dell Precision workstation with 32 gigs of RAM and a Core i7 yet it really thrashes this machine especially if spinning up several nodes to work with.  VIRL setup and maintenance is not for the lighthearted.  From the start, getting it installed is an undertaking as well as troubleshooting it is a beast if you have something go wrong with your install or something stops working like it should.

If you are looking for satisfactory results, you simply will not get that if you put VIRL on a weak machine or a multipurpose machine that is used for other things.  VIRL needs its own dedicated hardware to really run correctly.

Now the above is kind of a negative slant with VIRL and it does have some serious resource and complexity issues, however, what about the good.  If you are into hardcore Cisco networking, VIRL is definitely for you.  VIRL allows you to work with the newest images of many of Cisco’s products, asa, xr,xe and nx-os images, as well as many datacenter class nodes that most simply would not have the opportunity to get their hands on.  VIRL is fully featured (for the most part) in both layer 3 AND layer 2 switching capabilities which is something that especially GNS3 lacks unless you get your hands on cracked IOU images which are out there.

GNS3

GNS3 has been the beloved emulator for so long now with Cisco studies and it does so much.  Most CCIE’s have used GNS3 as their software emulator of choice and even the CCIE labs have been taken on them.  GNS3 has been the defacto standard with learning Cisco IOS.  So with VIRL is GNS3 irrelevant?  Not so!

GNS3 is still a great tool in learning and preparing for exams.  The thing I love about GNS3 is the simplicity it brings to both setting it up as well as the efficiency with which it runs.  On my healthy precision workstation, it barely taxes it to have 10 devices running or more.  With VIRL, that same number brings my machine to a crawl.

For me if I am still banging out configs quickly and easily, I will launch GNS3 over VIRL just from a time and efficiency standpoint.  GNS3 also still feels a little more intuitive to me than VIRL with the controls of the interface.

Update

Read the new posts here on GNS3 VM as well as how to use VIRL images on GNS3!

• Setup GNS3 VM on VMware ESXi
• Use VIRL images in GNS3

Packet Tracer

Many don’t even know about or use packet tracer, but I have found that it is an excellent little tool to test high level ideas.  The functionality of the devices you get is VERY watered down compared to GNS3 or VIRL, however, if you simply want to test a theory of connectivity between a couple or more devices, it is a simple and very effective tool to launch and test something really quickly.

If you have been through a Cisco Academy program you have access to this for free.  It is also widely available on the net in the student edition trim if you look for it.

Thoughts

The VIRL vs GNS3 vs Packet Tracer which one question is still going to be a matter of personal preference and for my opinion it varies largely on what you are trying to accomplish.  Working with modern IOS images and devices I think VIRL is very well suite.  GNS3 is right there with features and functionality and is much easier to work with, much less complicated, and resource intensive.  Packet Tracer is another neat little tool that can be used effectively in testing and quick scenarios.