1. The question is to which hardware component of the switch does the physical MAC address is assigned?
Like motherboard of a switch? Is it physically burned on somewhere?
2. Does a MAC address of a routers Ethernet port is physically burned on it or is it virtually assigned?
3. regarding STP, where do MAC for Vlans come from ? I saw some examples where vlans have the same MAC address (plus system id of vlan number), and some examples of different MAC for vlans that came from interfaces! Yet, switch interfaces have virtual MAC addresses, right?
1. Depends on the switch
3. See 1