Linux DynaMIPS + 4x3550s ???


Hi all,


I could scrape enough money together in the near future to buy 4x3550s and I was wondering how much mileage I could get out of using the 4x3550s in lieu of the 2x3560s + 2x3550s currently on the lab blueprint.

I can use DynaMIPS and the 2950 I currently have to break out to my 3550s.

Honestly, I need a lot of work in switching and was thinking that by the time I get to the point of appreciating the differences between 3550s and 3560s that:


1.  I will have enough money to either buy (or borrow) a pair of 3560s.  I already got a friend who is a target.

2.  They will be a bit cheaper.

3.  I would have developed my switching skill to the point where I could rent some racktime to touch up on the 3560-specific features.


I tried to rent some racktime, but the 5.5 hrs go by quickly when you are a total noob to switching and you are trying to understand the whole remote topology.  If I can go through the process of putting the topology together myself I feel I will be more intimately aware of my setup and can do more learning without the clock of racktime clicking.



Thanks in advance guys!



  • Hey Mate,


    I think if you had access to 4 3550's and no 3560's it wouldnt be the end of the world..  A couple of comments though.  Be familiar with the differences:



    What sticks out for me is the qos differences and lack of private VLAN and IPv6 support.


    Dont expect the secondhand 3560 prices to drop dramatically any time soon.  Thats just my opinion.  They seem to have held their value pretty well until now and I think will continue to for a while.  Unless everyone upgrades to 3750's or Cisco release another similar positioned device.. unlikely?..  So when you can upgrade two of your four 3550's to 3560's when you see a good eBay price..


    If you havent already have a look at ditching the breakout switch for some USB NIC's or some quad port NIC's.  This will give you more functionality and less headaches which means more quality time to lab.


    All the best!  HTH.





  • Greetings human,
    I have found it much more productive using the 4x3550 (with 3 quad port NIC) with my setup (ubuntu, quad core) - has given a great insight without the full headaches and expense of the full lab.


    Hi peachhead,

    Any reason you don't like the breakout-switch scenario?  Does something not work like it's supposed to, or is it too much of a kludge for you?

    One question I had about the quad-port NIC scenario is:

       1.  How  many quad-portl NICs do you need?  Because it seems to me like there are more than 4 router-switch connections in the design topology.  I'm not sure how many NICS I would need, but judging from the switching diagram here:



    It seems like it would be 8+.


    Hi MartinH,


    Did you buy 3xquad-port NICS?  Isn't that kind of expensive?


    If you have used it under Linux, what cards would you suggest?





  • Read up on the hacki forum, the extra info you read will serve you well :)


  • Hey Mate,


    As suggested have a good read of  The breakout switch method limits you somewhat.  For the current IE topology you require 12 interfaces so 3 quad port NICs.  I use D-Link DFE-570TX's in Ubuntu which work fine. 





    Funny you mention that!  I was just reading up on the hacki forum as I was waiting for responses.  I was even shopping for some quad-port cards [H]



    I was doing a little shopping around and I noticed the DFE-570/580s seem to work well under Linux but they seem to be in short supply on eBay and I don't think D-Link sells them anymore.  Did you use a specific eBay search string?


    Just doing some looking around, it seems like the only 4port PCI cards you can come by are used.  I guess the industry is moving away from 4port PCI cards unless they're crazy expensive.


    I think the quadport is a bit more convenient, but the USB thing seems kinda attractive also.


    Anybody have a good source in the USA for quadport cards known to work well under Linux?

  • They are hard to come by.  I was lucky enough to get some on eBay however have not seen them since.  They are approx $300 new as well which is steep.  I would recommend finding out the next best card that works natively in Linux and source some of them..  Research adaptec and whatever else is the latest recommendation on the Hacki forums.  Stay away from the Sun x1034a.


    Hi peachhead,


    I am still looking around for a good deal on the quad-port NICs.  I read that you said there could be a few issues w/ the USB approach.  If I can't find a good deal I will have to look into it.  Meanwhile, I am trying to huntdown a good deal for an Adaptec quadport card.


    Anybody have any info on USB ethernet?

  • Hey Mate,


    I usually dont like to speculate however I will give you a quick run down of the USB NIC approach.  Please keep in mind I have only tried this with a few of them and not the required 12 to emulate the IE topology.  I have previously heard you can have issues with how you interconnect the NIC's via USB hubs to your PC.  One thing that comes to mind is using the same chipset USB NIC's on the same hub.  Recently Scott Morris confirmed he had 12 of them, all the same chipset working find on his Macbook.  In the same conversation someone however confirmed the same chipset issue was indeed an issue in their configuration/setup.  Its definitely a cheaper option and if it works then you're set.  Just dig a bit deeper and make sure the platform you intend to run them on whether it be Win32/64/Linux32/64/Mac will operate fine with your chose of USB NIC chipset's and hubs.


    Good luck, please let us know what you end up using and how it works for you.






    Hi peachhead,


    Thanks for the reply.  I'm running Slackware 2.6 kernel.

      I can see how that might be a problem.  I will do a little searching in my spare time for the USB vs. quadport card prices, but I now have a handle on what the potential issues are.


    There are pros/cons for each it seems.  The quadport is a bit cleaner, and once you have 1 quadport come up, you can safely assume you can buy 2 more and you're supported OS-wise.  The drawback is you can't conveniently return it anywhere since you probably bought it 2nd hand.  I would love to see the look on someone's face who happens to look at your computer and see 12/13 ethernet ports on the back of it.


    The usb method is cheaper, but you never know it will work until you get all 12 up and running.  Having to run a few different chipsets seems to me that something is not quite right w/ the support.  I suppose I could use the breakout method until I can find a decent card.



  • Its quite funny.  I have my lab setup at work.  I am actually the only network engineer in the office and as its mostly sales and IT consultant folk so they all look at me like im some kind of mega geek.  4 switches all patched in together to a pc with pointless blue LED's and 12 cables running to the switches.. cisco press books everwhere, a whiteboard with INE diagrams and workbooks scattered on the desk.. two big monitors and empty coke bottles scattered around.  They ask what its all for and after 2 minutes of trying to explain the CCIE program I end just telling them its to make the Internet go faster...


    Are you somewhere in the southern hemisphere by chance?  I have two x1034a's sitting here doing nothing so if you happen to be close by you can borrow/try them out... They wont work in a system with more than 2GB memory though..  Good luck.

  • Hi,

    Depending on the box you have (the disk controller makes all the difference) you could use VMware ESX3.x with a VM running Ubuntu, and have a trunk link running to your 2950 switch, where all 'router uplinks' are patched from your 3560/3550 setup.

    So you would have your 4 3560/3550's interconnected, with the router links going to your 2950 switch. On this 2950 you could configure an access vlan for every port and have this trunk going to your ESX box. On the ESX box you could use a separate vSwitch where the same vlan's are known. On the vSwitch you could configure a trunking portgroup (vlan 4095) that goes to your Ubuntu VM. Effectively this creates a trunk from your 2950 to your Ubuntu VM :)

    Now the only thing left is to create the dynagen lab file, which connects your routers to the correct vlan's/ports. Using this setup, you would only need as many cables as you have router uplinks (plus the interconnect cables ofcourse) and it'll save you money for the quad nics, because you only need one (or two, if you wish) :)


    At this moment I'm using an ESX setup (hence the option above) with an Ubuntu VM. This box has a 2.4ghz quad core cpu with 8gb of memory. The VM only needs ~3ghz and about 2 gigs of ram, ofcourse with correct idlepc values. I do not have real switches, but use ethsw16 modules instead, which works most of the time. So I run about 6+4+3 = 13 routers. Linux rocks for this, as I get ~50ms latency end to end.

    I have to be a bit 'creative' for labs that require features I can't use :) For the remaining gaps I borrow some switches from work, so I save myself a whole bunch of money.

    The ESX box cost me about 700 euro's to build, one year ago. I guess you could build the same with more memory at this moment depending on the motherboard.

    I hope everything is clear, as it is hard (for me) to describe in a few lines of text. I'll draw it out and make a sample lab file if it isn't.

    just my 2 cents ;)


  • Are you somewhere in the southern hemisphere by chance?




    (Just noticed you were +10)



  • OI OI OI!


    +10 is great.. although when my alarm went off this morning (Sunday) at 515am so I could get up for a rack rental I didnt think so... :p


    Is it an advantage to use 3 quad-card instead of trunking it out to the 4 3550 real switches?


  • Interesting... I'm hoping to do the same thing soon too as I've just secured two 3550's for free. I think I'll have to find two cheap 3560's (if they exist!).


    I was planning on placing a dell switch in the middle and connect the dynamips routers to logical interfaces on the box trunking to a switch in between the dynamips box and the 3550's. Does anyone know if this would work?








    Hi peachhead,


    Actually, I'm in the US but I appreciate it. 


    Your tip on ser2net was GOLDEN though.  I just tried it out and I think it saved me from either having to buy a terminal server or setting up some sort of access VLAN scenario.  I'm glad I can console into my switches from my PC now though.  Thanks a million for that tip!!!



  • Overview:

    Breakout method:


    That's exactly what I meant!, only thing I've added is the VMware part :)


  • - Server running FreeBSD

    - 3x quad-port Sun NICs (I got 3 on ebay for $28)

    - 2x 3560

    - 2x 3550

    - 4x USB->Serial adapters from

    Best way to go.

    Don't bother with the trunking to a switch thing. When quad-nics are as cheap as they are, it's not worth the extra trouble.

  • IPv6 Freely, can you explain a little more?

    I got my hands on two 3550's for free and I'm trying to scrape together money for 2 x 3560's at the moment.

    Sorry... I'm just not too clear on how to go about this.



    On Tue, Apr 21, 2009 at 3:08 AM, IPv6Freely <[email protected]> wrote:

    - Server running FreeBSD

    - 3x quad-port Sun NICs (I got 3 on ebay for $28)

    - 2x 3560

    - 2x 3550

    - 4x USB->Serial adapters from

    Best way to go.


    Internetwork Expert - The Industry Leader in CCIE Preparation

    Subscription information may be found at:

  • While I'm waiting on a quad port NIC that I was going to test out, I decided to test out some cheap [H] FastEthernet USB adapters from eBay.  I got 4 of these:



    I am running Linux kernel the driver was instantly recognized and I had no problem.  The cool thing about this was that each adapter was about $5.

    Even at 12x, that's only about $60 + 2 USB hubs.  I think I will order about 8 more and see if I can get 12 eth NICs running on my system.  Even though I'm optimistic about the 3x quad NICs scenario, I run a laptop that has GNS3 running also and it would be nice to emulate an IEWB rack in case I am able to get 3550/3560 access at work or another non-home location.


    Hopefully the ports on the USB hub I ordered is spaced out enough to acoomodate these devices, they take a bit more space than a flash drive considering the RJ-45 blueprint.


    I got that quad port PCI NIC in today, and I spent a heck of a long time 5+ hours getting it to work properly after having it crash my Linux box a couple times.

    I had 3 PCI slots available on my PC, and this quad port NIC is soooo freakin long that my case gets in the way w/ one of the PCI slots.  A bummer!!!

    Another thing is that many of these quad port NICs are REALLY old so you could be dealing w/ flaky hardware anyways.


    I think I am definitely going the USB NIC route.  My driver worked right out of the box, I know it's supported, and it was only $5/NIC.


    Plus, you have the added bonus of not filling up your PC slot w/ 12 NICs.  Because, let's face it.  After DynaMIPS, a PC w/ 12 NICs inside of it will really not do you much good.

  • Currently I am using 3 Quad-NIC card solution, it looks like the earlier version of the Sun Quad-NIC card works fine. But later version NIC card will give you some problems like rename the interfac or MAC address shows up the same. I have 6 Sun Quad NIC cards. 3 of them are 06Rev50 which give me big problems. The other 3 are 01Rev50 or 01Rev51 and it was recognized by Ubuntu without any problem.

    Also, it looks like Sun card won't work at memory above 2GB (This is what I read from other thread. Didn't test it personally).


    I would like to know your test result with USB NIC solution. Scott Morris didn't run into problem but someone else run into problem with same chipset or other problem.


    (ps: I am also using 4 3550 switches to do my study as well and I am still in the middle of building my lab.)






    So far, I tried plugging in 4 of those USB cards into a powered USB hub and Linux recognized them easily.  I think this is by far the most painless and inexpensive route if your current Linux kernel supports the driver either as a module or built-in to the kernel.  I think I had many things built-in to my current kernel as loadable modules, and now I'm glad I did.

    The good thing is that there is support for this device in Linux as it is currently working in my Slackware system.  The chipset used is:

    Realtek RTL8150L


    I used to think the quad-NIC was the sexiest solution.  But not anymore, now that I consider these drawbacks:

    1.   Sticking old/used PCI cards into your new server and taking up all your PCI slots. 

    2.  The power is drawn from the system's power supply and you are generating extra heat in your server/workstation.  A powered USB hub should be able to provide power for the USB slots.

    3.  The cards are pretty damn expensive!!!  I can get all 12 USB NICs for about the same price as I paid for just 1 quad NIC.

    4.  The quad NIC I bought, which I was even lucky to find, was an Adaptec ANA-6944A-TX.  That thing is sooo freaking long that it could only fit in 2 of my available 3 PCI slots.  What that means is that I couldn't even go that route for a 3x Quad NIC as one of my existing PCI slots was unreachable.

    5.  These cards are DAAMMN cheap on  You tell me how you can beat 1 brand new USB NIC on eBay for $5.00.  Even a few USB powered hubs are about $10-15 each.

    6.  When you don't need 12 NICs attached to your system, you don't have to have them in your system.  3 90's era quad NICs are not hanging around in your system.

    7.  I have a server and a laptop.  I can easily move the NICs between my server and laptop in case I have to go to work for equipment usage.

    *** Mind you, I haven't tried this USB solution on 12 NICs, but I don't see how that would be a problem considering that Linux supports 16  ethernet interfaces.  I only bought 4 upfront just because I wanted to make sure it works.  If someone had a problem with 12 USB NICs, my guess is that it's either a driver problem or they weren't using a powered USB hub and the system's USB hub wasn't able to deliver adequate power (not to mention that I believe there is a USB hub limitation on the amount of devices that can come of a USB port)  ***


    I can offer a few pieces of advice on making this solution work.

    1.  If you buy a USB powered hub, make sure it is a hub that has USB slots oriented horizontally.  I bought a few 7:1 USB hubs that were oriented on top of each other and not all devices fit.  Oh well, I guess I can use it for all my other peripherals.  This is the type of USB hub you want b/c that fit those USB NICs just right with no room to spare.



    2.  Linux seems to arbitrarily assign different ethernet interfaces on bootup.  What I did was hard-bind a particular MAC address to a specific interface (eth0, eth1 for example).  In Slackware, it was somewhere in /etc/udev/rules.d/.  Needless to say, this is absolutely crucial considering you will be working on an existing topology and since the USB NICs will represent a router's specific ethernet interface, you want it to be the consistent.



  • Hello, it is a very interesting thread. I'd like to prepare my own lab too, but i can't afford to buy a server with 12nics.

    So i am planning to buy a desktop computer with your solution of usb/ethernet card. Can you give me please som advice about the configuration required to run such a lab? (cpu, motherboard, ram ...).


    Many thanks




    If you can't afford to buy a server w/ 12 NICs, don't buy a server w/ 12 NICs.  Go with the USB ethernet card scenario.  I tried it w/ 4 USB NICs and will order 8 more to try it on 12.

    Now if you intend to run Windows, you would probably need to ask somebody who has tried it w/ Windows, b/c I don't run DynaMIPS on Windows.

    As for CPU + RAM, the general rule is to get as much as you can afford.  Buying a system now, you should probably consider 4 GB RAM as your minimum and you could easily be looking at a quad core CPU.

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