16 comments on “Turned my back [slightly] on Dynamips!

  1. Stephen,

    I am about three – four months behind you in the study cycle and have come to the same conclusion.

    I am working full time and flying coast to coast so it has been almost impossible to plan for rack time. I also never really know what time zone I will be in so getting rack rental time slots to match my schedule has been very difficult.

    I have had slightly better luck with dynamips. I bought a macbook pro and I can run the full lab scenario reasonably well and have gotten quite far in my labbing with dynamips/macbook pro.

    The problem is when I things don’t work. Is it not working because of my config? Is not working because of some Cisco “feature” or is it not working because of a dynamips problem? I have had most of my issues on complex multicast scenarios. I have never gotten the debug multicast debug features of IOS to run quite right. I have watched a packet go in on a virtual wire and not come out on the other end! I have spent many many valuable hours tracking down “flakey” situations.

    My lab is in early September, and if I do not pass, I will have to regroup and will most likely buy a rack of 1841 and 3650s. I can get them on ebay of a good price. That way I can access my rack at the time and place of my choosing

    I have enjoyed your blog and wish you the best.


  2. Mate, I passed SP purely on labbing on Dynamips. I didn’t use GNS3 though, as it would crash sometimes, I went the old school CLI Dynamips. But to get this lab working I went for a PC upgrade to 4GB, quad-core CPU, Vista Ultimate. I could easily run 12-14 devices.

    I never did rack rentals as my job requires tier 3 on-call support so I didn’t want to commit to that, i’d rather just Dynamips running and I even use to VNC to my home PC (my lab) from work and if I had a bit of time i’d go through some workbook mini-labs and then go for the big labs too. See, I never tried to do the moc-labs within 8hrs, I use to do them til they were finished and working, even if it took me 12hrs (as I would start in the morning at work and finish later at night at home).

    The Lab I passed was alot more vague than the first one that I failed (I think I should have asked for a re-read judging by that others have been doing it and passing). The 2nd lab I passed the questions were shorter but asked for more in-depth knowledge and didn’t give clues or steps on what to configure (the 1st lab I did had loads of hints in the questions).

    Anyways mate, my point is use dynamips, upgrade your pc for it and dedicate that pc to be your lab. Don’t use GNS3 as I found it unstable too (especially when you have the VPNs and multicast running with MP-BGP). Use both vendors workbooks, use Anthony Soares mini labs, and mate go through the Cisco doco site we have access to in the lab, spend like 2 weeks on just that. Don’t have to read it word for word but just find out where things are and map them on a paper.

  3. Lately I’ve spent abit of money to upgrade my PC to Core i7 920 with 6GB of RAM. In terms of performance, it’s hard to tell whether I’m working on real routers or Dynamips-emulated routers. I’m still currently going through IEWB-SP-VOL2 labs slowly without having to worry about rack rental time. The CPU utilization is generally less than 50% for a fully configured SP lab topology, with WinXP. I believe it can perform even better if I run it over Ubuntu, which I should.

  4. I’ve used a combination of dynamips and rack rentals as well and I really love it! I hate it when dynamips crashes or fails on something. I like real hardware and the timeslots are a good thing to me to really schedule free time and really sit at my desk. If I have my own lab I would skip over and never practice.

    Besides that you should ask your employer for study time, I never used it since I can study all weekend, but my employer is pretty generous with time for CCIE especially .

    You can use Dynamips for 100% of SP topics, just buy extra hardware or create a dual-boot with Linux, it runs much much better on Linux and with your set-up you can easily emulate 20 routers.

    Rick Mur
    CCIE2 #21946 (R&S / SP)

  5. Well Im Running my LAB on ubuntu Karmic Alpha, Compiled Latest Dynamips (5th May 2009) from source, and using CLI Dynagen, and it works gr8 with Core 2 Due 2Giga with 2GB RAM. Im running Full LAB with Almost all technology and CPU remains 100% still it works Smooth.

  6. Hi Stephen,

    Having a physical rack at your disposal is first rate. Wise decision. I finally have mine assembled using (6) 3640’s, (1) 3660, and (2) 2811’s.

    Good luck in your studies!

  7. good post. I prepared for my ccie sp using dynamips and rack rentals:
    all preparations were done on dynamips (minilabs, IE small labs, IE full labs) then I used rackrentals for full labs again. I did not use GNS3 at all but dynamips with dynagen – the cli interface towards dynamips – the configs were from InternetworkExpert web site. The PC has 4 Q660 processors, 4 G B of RAM and runs WinXP. No problems with running full configs (full labs done on Dynamips). I want to come back to try again and i don’t know exactly what to do: redo the same steps meaning using Internetwork expert package or use IPexperte training pacakge ….

    • Focus on your weaknesses which you will have identified from your 1st attempt. In my case, it is to [1] speed up the L2/L3 sections and complete BGP & Basic MPLS before lunch. [2] to complete the MPLS VPN Section which I did not do on my 1st attempt.
      Also systems management I did not know well as I use Orion Solarwinds for that!

  8. Can you please suggest if a Intel Xeon 3.2GHz CPU’S (two CPUs) with 5 Gb RAM with linux installed is worthwhile investment for me to setup a dynamips lab for CCIE SP.
    Or is it good to have quad core.? please suggest

    • Hi Sundar, u want a pc or a server 😉

      a single quad with 4 gig is more than enough for 16-18 routers. You just need to tweak the config file properly to run the routers on multiple instances instead of just 1 since windows can max allocate only 2Gig / instance of any service.
      I can confidently say it from personal experience while preparing for the R&S lab.

      I would suggest u go in for a custom heatsink though. I use the intel heatsink from thermalright. They provide gr8 cooling. (i am in no way associated with them, just a happy customer).



  9. Hi Sundar,
    If you are running Linux then that should be fine – If you are running Windows then a Quad Core would be needed – That’s my $0.2.

  10. Hi Stephen,

    I passed the CCIE R&S 4 months back and have begun practising for the SP Track.

    I am using a Quad-core with WinXP 64bit, 4Gig Ram and GNS3 0.7RC1.

    I have had no problem running 14 routers for the R&S Lab for practicing end to end routing, used the Rack rentals on for the switch part.

    So far i have had no problems running 14 routers for the SP Lab too on my pc with full fledge MPLS & QOS. The CPU averages about 40-60% but for that i put a thermalright custom cooler, and never had a GNS Crash problem.

    In my opinion, practicing on GNS is the best option since you can suspend the lab when required, continuing with the lab later does not involve any preconfiguration delays and u can do it as per your convenience without any timelines to follow.

    HTH, and best of luch with the CCIE SP preps.

  11. I want to setup my Dynamips for SP track and I am wondering what IOSs I need to have to be able to go through the LABs?

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