First of all, for those who have just started using Dynamips for their studies I strongly recommend looking over the following link Running IOS on PC. On that page you may also find the links to the Dynagen topology file for the previous edition of our virtual topology. As for GNS3 fans, Brian McGahan is working on the topology for this platform and plans to release it soon as well.

Now for the new Dynamips topology – the main change when comparing to the old one is the replacement of 3640 platform with 3725 router, which supports IOS 12.4T. Best of all, the 3725 routers with “ADV. ENTERPRISE SERVICES” images support most of the IOS features required for the updated CCIE R&S exam, including MPLS VPNs, ZFW, EIGRPv6 and OER. Additionally, the use of 3725 platform means we now have the built-in FastEthernet controller, which allows to get rid of the NM-4E modules used int 3640s. As a consequence, some interface names have changed too – specifically, all “Ethernet 0/X” interfaces have translated to “FastEthernet 0/X”.

You may find a sample .NET file for Dynagen here; the file has been created with a dual-CPU workstation on mind. However, a more powerful platform is recommended to simulate the full CCIE R&S rack (10+3 routers). Notice that you need to provide a correct path to the IOS image used in the topology as well as obtain the image itself. You may also need to edit other directory variables, such as working directory in order to get working configuration. Of course, you may want to play around with the IdlePC value to obtain optimal performance with your hardware platform and operating system. As a side note, two good tricks to reduce the load on your CPU

1) Disable spanning-tree for all VLANs in SW1-SW4 and provide a loopless topology by shutting down unused links and connecting switching in a star topology.
2) Shut down the backbone routers and only bring them up for testing purposes.

And finally, for the Dynamips version of our Full-Scale Labs Workbook. This one is coming right after we finish updating the “classic” VOL2 for the new R&S lab blueprint. You may expect the first “fully-Dynamips” labs to appear by the mid of October.

Happy studying!

About Petr Lapukhov, 4xCCIE/CCDE:

Petr Lapukhov's career in IT begain in 1988 with a focus on computer programming, and progressed into networking with his first exposure to Novell NetWare in 1991. Initially involved with Kazan State University's campus network support and UNIX system administration, he went through the path of becoming a networking consultant, taking part in many network deployment projects. Petr currently has over 12 years of experience working in the Cisco networking field, and is the only person in the world to have obtained four CCIEs in under two years, passing each on his first attempt. Petr is an exceptional case in that he has been working with all of the technologies covered in his four CCIE tracks (R&S, Security, SP, and Voice) on a daily basis for many years. When not actively teaching classes, developing self-paced products, studying for the CCDE Practical & the CCIE Storage Lab Exam, and completing his PhD in Applied Mathematics.

Find all posts by Petr Lapukhov, 4xCCIE/CCDE | Visit Website

You can leave a response, or trackback from your own site.

29 Responses to “INE Updated Dynamips Topology”

  1. IPv6Freely says:

    Well, no real change for me I guess… other than the platform and IOS. I just use the normal workbooks with Dynamips. The only difference for me is anywhere INE says to use S0/x, I use S1/x. No big deal :)

  2. Muhammad says:

    Thanks Peter. I was desperately waiting for that and you did it mate.

  3. Muhammad says:

    Peter…Regarding shutting down the backbone routers and bringing up only for testing purposes, i did not get this point at all. I believe BB Routers need to be UP all the time as the scenario could be to connect to them via FR such as R6 to BB1 or BB3 which needs to be up throughout the lab. Moreover, there could be IPv6 connectivity with backbone routers. Also BGP/OSPF/RIP needs to be run with them with Internal R1–>R6 Routers or pre-configured. So could you please explain this point.
    Thanks in adv.

  4. As mentioned above, the tip for shutting down the BB routers is for reducing CPU load. Having BB devices that are configured for multiple routing processes will add to the CPU in the virtual environment.

    If you have plenty of CPU to spare, then keeping the BBs running is not an issue.

    If you do not have sufficient memory / processor, it may present the situation where having the BBs running all the time may make all the devices seem sluggish. If that is the case, you can have the BBs off while configuring topics, and then enable them when you need to test.

  5. Nish says:


    Can you provide some assistance in how to setup the inital conifgurations for the switches SW1-SW2???

    I have all of it setup…just struggling to load the initial config for the switches in Dynamips…

    • You’ll need to edit the way the VLANs are created, and then change the interface numbering around. The Router IOS support for the EtherSwitch module requires that the VLANs are created in VLAN database mode, where with the Catalyst IOS you can use either.

  6. Muhammad says:

    Marvin…Thanks for your response however that’s understood and is easy to understand about slugginess and cpu load. With Quadcore it is not an issue however with core 2 duo, slugginess is present. Infact You did not get my point. What i said is that routes are advertized from BB to internal routers, such as IGPs. Now for connectivity testing, sometimes you do some change in the network and this affects your reachability to the BB. with me that has happened several times and even when i appeared in the Real lab two months ago. So i was thinking is that it seems to be a tedious task to shutdown and make the BB routers back again for testing purposes. This process is dynamic and can’t just be so simple to test. Hope you understand my point this time.

  7. Ferret999 says:

    Awesome been waiting for this for a while Petr looking forward to the new Dynamips workbook

  8. nwachonky says:

    concerning this dynamips update, can the update be used for IE vol 1 workbook or just for the dynamips version of the full scale vol 2 labs.

    when will MPLS be added to Vol 1


  9. ilorah says:

    when will MPLS be added to Vol 1


  10. ilorah says:

    concerning this update, can the new topology be used for IE vol 1 workbook or just for the dynamips version of the full scale vol 2 labs.


  11. Nadeem Rafi says:

    From the beginning i was always using 3725 IOS and my own topology. As 3725 is more stable than many other Platforms.
    with core 2 on Linux i think full lab is do able.

  12. Zeus says:

    What is the recommended configuration of the laptop if I am planning to fire 13 routers concurrently?

    Is Intel Core 2 Duo 2.1 GHz T6500 with 4 GB of ram enough?

    thanks in advance

  13. AJ says:

    Good Job Guys,
    Is there any list of all features that cannot be deployed with the emulating platform dynamips so when I finish preparing with dynamips and start racktime I know excactly what I will need to focus on?
    Thank you guys!

  14. ippo says:

    I bought a Dynamips Lab v4.1 the other day. Can I be entitled to use the updating vol2 without any cost?

  15. Bobby says:

    I just migrated my dynamips to the 3725 using the 12.4T10 advanced services image. I am using Vista on a 2.93 Ghz and 3GB. Getting all 13 routers up with basic layer 2 configs was not too bad. However, once I enabled RIP (Vol 1 labs) on all of them it was maxed — CPU close to 100% and RAM at about 85% with the following tuning knobs: ram = 128, mmap = false, ghostios = true,and sparsemem = true.

    The tip on disabling STP and using a basic star topology was huge!!!! It really quieted things down. Now the CPU is about 40% and RAM at 71%. I am sure I will still need to go to my dual-PC setup when doing the OSPF and BGP labs (this is my 2nd time going through vol 1 labs while waiting on the 4.0 updates).

    • @Bobby

      yeah, the problem with STP is that 3725 ESW module runs PVST+, i.e. a separate STP for every VLAN. Effectively, you have almost every switch sending a BPDU for EVERY VLAN on every inter-switch link. That’s painful :) For many scenarios you may revert to just the simply star L2 topology and focus on L3+ tasks. This allows completely disabling STP and saving tremendous amount of CPU cycles.

  16. Bobby says:

    Roger that Petr. Thanks again for the great tips. Yes, to do the L3 labs, I will be running the little star topology–no redundancy. I don’t plan on losing any links ;-)

  17. nasser says:

    Eagerly awaiting the release of the dynamips workbooks – any updates?

  18. Bob says:


    Just starting my lab preparation with the INE workbook VOL 1 and I am having some difficulty in getting the switches working using dynamips.

    Can someone post the working config for SW1, SW2, SW3 and SW4 in order to continue with my labs?


  19. Eniola Olaleye says:

    Hi Petr/Anthony,

    Hope you guys are doing fine.

    Well I am having issues with V5 Dynamips lab; the 3725 IOS keeps reporting that there is no space on the vlan database to store he vlans, even after squeeze. How can I solve this problem or go around it.

    I will really appreciate your speedy response.



  20. Gbenga Adesoba says:

    Great post, Eniola Olaleye, can we hook up, please, my ID is: adesoba (at) Hope to read frm u.

  21. Massimo Ballerio says:

    I am using the c3725-adventerprisek9_ivs-mz.124-15.T9 image but I cannot find some commands. E.g. in (config-if) the switchport mode command has only trunk or access options, and I cannot find the dynamic portion. Is there an explaination ?

    • Hello my friend!

      Yeah – the switch module on the 3700 is a really terrible way to practice the switching because of so many missing commands as you have seen. Most connect real switches to their dynamips routers – or just rent some time on actual switches in order to practice those lab portions.

  22. Massimo Ballerio says:

    The 3642 version does not look any better. Is there any available simulator option ? I bought some graded labs tokens, but with my 5 months old kid it is very difficult for me to plan and find 5.5 continuous hours to practice. Up to last week I was able to get online and catch some leftovers of a rack slot on the fly, but as of now it looks like the only way is to reserve a full slot at least a couple of days in advance.
    Please give me any piece of viable advice.


Leave a Reply


CCIE Bloggers