Is 4GB of RAM good enough to run GNS3 smoothly?

Hello everyone...

I just sold my MacBook Pro to get something more portable and before I purchase a new computer, I just wanted to see which would be ideal / benefical for me when it comes to RAM.

I know if you tweak the Idle PC and Idle Max values, it helps your computer's CPU utilization drastically, but would 4GB of RAM be good enough to run the INE labs good?

I have heard from a few people that it is recommended to use a computer with 8GB of RAM. I know that the more RAM the better, but would 4GB of RAM be ok? If in fact I do need to get a computer capable of holding 8GB of RAM, I guess  I will be getting another MacBook Pro... Whatever computer I get, it's either going to be an i5 or i7.

Thanks in advance.



  • More than good enough. I run the entire INE topology (minus my 4 real switches) and it doesn't break a sweat on 4GB.


    Just remember, every router does not have to have 256Mb ram. The BB routers don't for sure. All mine are 3745's with 142Mb of ram

  • Hi All,

    I also want to take this opportunity and check about GNS3 versus Dynamips. My Co worker mentioned that he has used both of them and thought GNS3 take up more memory than Dynamips. Which one Dynamips or GNS3 easier as far as learning the tool and using it. which one Dynamips or GNS3 supports more commands? I heard that they don't support switches, so what we should do to run the whole INE topology with them.

    Thank you for your advice in advance.


  • Peersonally I much prefer dynamips myself

  • Hi Mellowd,

    Thank you for your response. Could you also please provide some feedback and reasons as it seems you have used both. Since switches are not supported by Dynamips,what is the solution to be able to run the full INE topology with either Dynamips or GNS3.

    Thank you


  • GNS3 is just a graphical interface for Dynamips.  Dynamips can run as a command line process with a helper program called Dynagen. If you are constantly rebuilding your topology, use GNS3. If you use the same topology over and over, like the one for INE's Workbook Volume 2, I would use Dynagen. 

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    On Oct 29, 2011, at 3:36 PM, "Ellie" <[email protected]> wrote:

    Hi Mellowd,

    Thank you for your response. Could you also please provide some feedback and reasons as it seems you have used both. Since switches are not supported by Dynamips,what is the solution to be able to run the full INE topology with either Dynamips or GNS3.

    Thank you


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  • Hi Brian,

    Thank you for your quick reply and great feedback. I have heard that Dynamips does not support switches. In that case, How I can use Dynamips to build routers and then I should make connections between routers in Dynamips and physical switches? Is there any other ways that I can use virtual switches working with Dynamips.  I am starting with work book volume I which I think does not have Dynamips version.

    P.s.w I listen to your Advanced Technology video on my commute to go to work and enjoy it very much. Thank you and all INE instructors for your great products.



  • Dynamips does not fully support switching. It does have support for the NM16ESW module so you can have basic switching. You can have access ports and 802.1Q trunks and basic spanning tree functionality. It will not support advanced features like private VLAN.

    Either you do as Mellowd and use real switches or you use rack rentals for the switching labs. 3560 is not that expensive any longer but its up to you how much you want to invest.

    You can connect the switches to Dynamips through quad NICs, you need at least 12 ports or you can use a breakout switch if you don't want to use that option. There are posts on the forum on how to do this and a lot if you google it as well.

  • Hi Daniel,

    Thank you very much for your great freedback. It was very useful. I will prefer to buy a physical switch connecting to Dynamips. as you suggested, I will do more research on Google and INE blog on how to make this connectivity.

    Thank you

  • Hey!

    Check out this...

    for Building...


    and this for taking a look how it looks like...


    I also prefer the way with physical switches.

    What about buying rack-time? Maybe that an option for you?



  • Thank you for sharing this. I am still researching on switch models. I know I need two 3550 and 2 3560s but there are different models and different prices for that. I have found that the minimum price for each of them is $1000 so It can go expensive. would you know any website offering cheaper switches. I have also thought about rack time but when If we want to do practice lab for more than a year to be prepared, that can also become expensive because for real scenarios on workbook volume II, we can not divide the scenario and do the rotuer part with Dynamips and switch part with rack time., we have to do all in rack rental probably. I wish I can build up my lab as soon as possible to be able to focus on practice.


  • you could get away with a single 3560

  • Oh.Okay. I am trying to setup the lab to be able to follow with INE work books. The diagram has four switches. QOS uses 3550 and we still need 3560. How Can I simulate INE work book with one switch 3560

  • Use the 3560 as SW1, the rest 3550s

  • Okay, thanks. Would you guys know any sites selling these switches with cheaper prices

  • Not in Dallas I'm afraid.

    Ebay seems to be the best place for these sorts of things. 3560s are still very expensive on ebay here simply because they are still relatively new. If you are patient you can sometimes get a good deal

  • Great. Thank you for your feedback

  • You can also do it with 3550s and some remote lab tokens you need to purchase to have the advanced abilities of the 3560 in relation to the 3550s.


  • I hav a Quad Core 2.7 Ghz PC with 2 Gb ram ... 


    and i can run around 28 to 30 routers smothly .... 


    Unix or XP ill reduce a resources utilization o lot


    Win 7 will add up your CPU utilization a lot ..



  • Thank you zool and Parakesh for sharing the experience. I have i7 windows 7 laptop. I am doing reserach on DYnamips part to get it running. I was just trying to find out if I need to have double or multiple NIC cards in order to connect physical switches to Dynamips. I am trying to set it up in such a way that I can do the whole lab part including both routers and switches.


  • Hi Elli,

    indeed GNS3 is heavier on the processor, but functionally it's just a shell ontop of dynamibs, I have set up the GNS3 map but would rather use the Dynamibs interface actually if I were to use my pc at all :) I went to INE rack rentals for easy config loading. I do use GNS3 still for small labs at the times i dont have a rack but it very rare nowadays. (Dutch taxes allow for deduction of study cost) I used this setup and only converted the .net from mac-os to windows.

    cheers Richard


  • Thank you Richard for sharing this link. I will follow on that. Can I load INE config from the work book if I use GNS3 or Dynamips. I assume if the machine itself is powerful enough I can upload the config to virtual routers. what about physical switches connected to Dynamips.



  • A single switch doesn't let you play arround with spanning tree or some of the nasty Catalyst features.  You need to understand L2 and also how to fix L2 - you are not going to do this with a single switch.

    In the lab you will have 4 switches so to get used to this you need to work with a similar topology.

    3550 are cheaper to buy, but all the switches in the lab are Cat 3560 switches.



  • Hi Elly,

    yes your machine will handle it perfectly, as you know Steve Jobbs knows how to
    efficiently use hardware much more thna Bill Gates does ;-)

    good luck with the studies
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