Why is the connection between KVM hosts in RouterOS called bridge but not switch?

RouterOS General
1

Why is the connection between KVM hosts in RouterOS called bridge but not switch? I doubt whether there is special meaning.

2

“switch” means that the routerboard has a hardware switch chip for wire speed forwarding at layer 2.
“bridge” is the CPU-based bridging of frames at layer 2, and it will probably not come anywhere near wire speed unless you have a very powerful host running RouterOS.

Since the KVM host is virtual, it has no hardware for switching ethernet frames, so it is only able to use CPU bridging.

This is the difference and it is indeed a very important “special” meaning.

3

Thanks! See the difference

Is it possible for those KVM routers to direct connect with each other without using bridge?

4

No.

switch is a name that has come into use for a multiport bridge that is quick and realized in hardware. Meaning, the older name bridge fits better in this case.