GNS3 analogues. Who knows what?

Question

Computer networks

Good afternoon,
In order to study networks in more detail, in particular, to experiment with network topologies and settings for routers, switches and other network devices, I became interested in analogues of the GNS3 network simulator.
I myself know about the existence of Cisco Packet Tracer, but as far as I know it is closed from free access.
There is also a Dynagen text emulator.
I know about a rather funny thing - NetworkSims. But it is paid.
I also know about Network Visualizer. In fact, as I understand it - the same as NetworkSims, only in a different wrapper.
Maybe there is something else?
Interested in any: paid, shareware and completely free.

Answer 1

Dynagen is a wrapper around Dynamips, a router emulator. GNS3 is used to visualize Dynagen/Dynamips rules + much more.
On the same GNS3 it is possible to run the emulator (via QEMU) Cisco ASA, Cisco IDS. Juniper (JunOS on QEMU) is also supported. And Cisco PIX (via pixemu).
Unfortunately, the L2 level is not supported in any way, or rather, there are switches, and not Cisco CLI.
Of the "conditionally" free GNS3, probably the only assembly with such functionality. Why "conditionally"? Because IOS / ASA / PIX / JunOS images still need to be obtained somewhere - they are not free.
A little more work with L2 allows you to work with Packet Tracer - it is also "conditionally" free - available to any member of the Cisco Network Academy.
Of the paid and available ones, these are Bosson NetSim, NetVisualizer, Network Sims - they have already been named.
Of the non-paid and non-available ones, this is Cisco IOS on Unix (in fact, there is one under Linux ;) ) - it contains the router and switch firmware and allows you to assemble rather complex architectures (used to prepare for CCIE as well)
Experiment with network topology you can also use programs like Open vSwitch or VDE (Virtual Distributed Environment) , which allow you to set the L2 level programmatically. I use VDE quite heavily with Qemu/GNS3.

Answer 2

Greetings! There is also Bosson NetSim.

Answer 3

As already mentioned, DmZ
Packet Tracer is free and permanently available to a Cisco Network Academy member.
However, it is updated no more than once every six months or a year, and many post it, so downloading is not a problem.
skill-admin.blogspot.ru/search/label/cisco%20packe...
There is a version for students in which Asa
cisco.edu.mn/Download
is available for the "old" version 5, the Russian interface language is available