Simulation of Layer2-3 switches on PC

Question

Cisco

Good afternoon,
In general, the situation is as follows, I am preparing for the Cisco exam, I do not have a reference iron with me.
Quite a lot of practical tasks.
I tried GNS3, but it simulates routers more, when you try to turn their switches using modules, it starts to get stupid and buggy, it works extremely unstable. PacketTracer simply does not know many commands, and therefore is not suitable for use.
On what would you advise to do laboratory work, or who does what?

Answer 1

Boson NetSim

Answer 2

Cisco IOU. There are images of virtual machines with a web face on the network. Everything works with a bang.
There is a list of unsupported features. http://www.routerereflector.com/en/cisco/cisco-iou-web-interface/features-not-supported/
I can drop the link to the VM in private.