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Posted (edited)

Was unsure where to post this because it covers a few forum topics. Settled for here coz it's where I'm most ignorant, so this is your chance to prove yourself ;) (And then I moved it ;) - Ric_ )

 

The mission, using vmware, is to simulate a link between two schools connected to some RBC/big intranet, like this:

     realLAN -----------------------           
                        |
                   vmware host(nat gw)
                        |
     vmnet8  ------------------------
                |              |
             router1        router2
                |              |
     vmnet2---------    vmnet3-------

 

After a lot of hunting for virtual routers I found DummyNet in VMWare, fiddled about & so far it does exactly what I want - two credibly slow links for vmnet links 2-8 and 3-8.

 

I'm just a bit nervous about RAM because each router runs with 92MB and I've got servers to throw in yet etc. So:

 

1) If there's a feasible way to cut that RAM down I'll probably find it.. eventually. Anyone currently really wizzy at FreeBSD care to take a peek at that VM for any obviously useless (if just being a router) memory overheads?

 

2) Has anyone done anything similar e.g. do you know of something else that I could use? I've still got a perfectly good LRP floppy somewhere that would do for basic routing, but a key point here is simulating a slow, lossy link.

 

[VMWare specific aside: I haven't tried it yet because it's not essential, but routes from the NAT gateway back to vmnets 2 & 3 would be good. Haven't got a clue how you tell it to do that - possibly just add routes to the host - don't know. Anyone?]

Edited by Ric_
Thread movement
Posted
Was unsure where to post this because it covers a few forum topics. Settled for here coz it's where I'm most ignorant, so this is your chance to prove yourself ;)

 

The mission, using vmware, is to simulate a link between two schools connected to some RBC/big intranet, like this:

     realLAN -----------------------           
                        |
                   vmware host(nat gw)
                        |
     vmnet8  ------------------------
                |              |
             router1        router2
                |              |
     vmnet2---------    vmnet3-------

 

After a lot of hunting for virtual routers I found DummyNet in VMWare, fiddled about & so far it does exactly what I want - two credibly slow links for vmnet links 2-8 and 3-8.

 

I'm just a bit nervous about RAM because each router runs with 92MB and I've got servers to throw in yet etc. So:

 

1) If there's a feasible way to cut that RAM down I'll probably find it.. eventually. Anyone currently really wizzy at FreeBSD care to take a peek at that VM for any obviously useless (if just being a router) memory overheads?

 

2) Has anyone done anything similar e.g. do you know of something else that I could use? I've still got a perfectly good LRP floppy somewhere that would do for basic routing, but a key point here is simulating a slow, lossy link.

 

[VMWare specific aside: I haven't tried it yet because it's not essential, but routes from the NAT gateway back to vmnets 2 & 3 would be good. Haven't got a clue how you tell it to do that - possibly just add routes to the host - don't know. Anyone?]

 

if you haven't already done so check out the wikipedia entry on open source and commercial network emulation tools;

 

Network emulation - Wikipedia, the free encyclopedia

 

Provides a good summary, shunra VE is the product i remeber looking into a while back, but the professional version is just too expensive. Other than that, the only tool i have any experience with is Opnet's IT guru - which are more simulation than emulation.

 

You may be able to get a developer license for one of the commercial products - i'd imagine they would be a lot easier to configure and tune than the likes of dummynet.

Posted (edited)

This is what I ended up doing. The vmware nat service doesn't appear to understand subnets etc., so I put one that does between it and and my two pretend school sites.

 

It wouldn't be as portable, but an alternative would be to bridge 'router nat' to the hosts real network rather than connecting it to vmnet8.

 

    realLAN -----------------------           
                       |
              vmware host(nat gw)
                       |
     vmnet8  ----------------------
                       |
                   router nat
                       |
     vmnet4  ----------------------
              |              |
          router1          router2
              |              |
     vmnet2-------    vmnet3-------

Edited by PiqueABoo
  • 2 years later...

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