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I want to simulate a large network of 40 routers with GNS3 or OPNET or VIRL or …

In the real network, routers route their incoming traffic (coming from an external network) and deliver it to an another external network. Total network traffic is up to 100Gbps (But I do not need to receive 100 Gbps traffic in the simulation!). The link between routers is a few kilometers of fiber optics.

Suppose there is no problem in buying servers and hardware.

GNS3 guide states that "GNS3 will provide around 1,000 packets per second throughput in a virtual environment"

Can I simulate such a network with GNS3 or OPNET or VIRL or …?

What is the maximum traffic that these emulators can support (using powerful hardware) on such a network?

What factors limit it? GNS3 or interfaces between VMs or Cisco images or routers or ...?

Thanks.

*** Edit ***

Suppose I want to run a GNS3 simulator and 25 vSRX routers on one system.

According to the information in Sizing your computer for GNS3, I need a server with 100 GB of RAM and 17 cores. I have a server with 128 GB of RAM and 32 cores.

Given that all routers and GNS3 are running on the same system, the speed of data exchange between them can be tens of gigabytes. is that true?

Is it really possible to exchange such traffic between routers with such hardware? If not, what is the maximum traffic? What limits it? If I run each router on a separate hardware and they are connected via cable, will the speed increase?

Is it possible to simulate such a network with another simulator such as OPNET or ...?

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  • 2
    GNS3 is by no means a tool to simulate network performance or emulate long distance links. It's used to model topologies and test configurations.
    – Teun Vink
    Sep 8 '20 at 6:27
  • Is it possible to simulate such a network with another simulator such as OPNET or ...?
    – Ali Ut
    Sep 8 '20 at 8:45
  • I'll spell it out one more time: emulators are not used for performance testing. They're in no way capable of doing anywhere near the performance of real hardware, since all instructions are emulated and no hardware ASICs for performance optimization are available.
    – Teun Vink
    Sep 8 '20 at 8:53
  • Ok! What is the maximum traffic with these emulators? What limits it?
    – Ali Ut
    Sep 8 '20 at 8:56
  • How can vSRX support 100Gbps?
    – Ali Ut
    Sep 8 '20 at 8:56
1

While you can very well simulate the general functions and workings of a network in GNS3 (or any other decent simulator), it's not well suited for performance evaluation.

GNS3 runs on normal host CPUs with considerable processing overhead, coming nowhere close to the wire-speed hardware processing that is pretty much standard today, especially in terms of latency.

If the datasheet specs and the vendor reputation aren't enough and you really need actual evaluation you should consider arranging a lab trial period with the vendor.

7
  • That won't work. I think people explained it a number of times now: these tools are not meant for performance testing. They're meant to simulate topologies. You don't do performance tests on emulators. As @Zac67 said, if you need to do performance tests, build a physical lab.
    – Teun Vink
    Sep 8 '20 at 8:48
  • Suppose I want to run a GNS3 simulator and 25 vSRX routers on one system. I need a server with 100 GB of RAM and 17 cores. I have a server with 128 GB of RAM and 32 cores. Given that all routers and GNS3 are running on the same system, the speed of data exchange between them can be tens of gigabytes. is that true? Is it really possible to exchange such traffic between routers with such hardware?
    – Ali Ut
    Sep 8 '20 at 8:52
  • If not, what is the maximum traffic? What limits it? If I run each router on a separate hardware and they are connected via cable, will the speed increase?
    – Ali Ut
    Sep 8 '20 at 8:53
  • Is it possible to simulate such a network with another simulator such as OPNET or ...?
    – Ali Ut
    Sep 8 '20 at 8:54
  • You do not do performance testing on emulators. I don't see in how many more ways we need to answer this question.
    – Teun Vink
    Sep 8 '20 at 8:56

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