I've become ultra confused all of a sudden.
Switch is a layer 2 device. So this means it deals with frames (builds and examines them). So when it receives a frame, it looks inside to see where the destination mac address is. But since the mac address is on some further away network, and not directly connected to the switch, how in the world can it decide which way to send it? The switch doesn't have a routing table so theres no way of determining. So it either sends it down a trunk link or out all the vlans associated with the source port. Now if its sending the frame out all the vlan ports then this certainly does not break up broadcast or collision domains. Switches have no idea of the topology of a network and therefor must be sending frames out every possible hole they can to get rid of it.
But this would end up being huge problems. If I have a router on a stick topology, with trunk link. And a frame gets sent out all possible ports and a trunk link, the packet is going to get to the source, then after being routed through the router and come back it will be sent to the source again. Also isn't it making a storm if the router routes the packet back to the switch and the switch then sends the same packet down the trunk link, since everything gets sent to the trunk by default?
Or not even with a trunk link. Just linked up to any router. If the mac address isn't directly connected to the switch it must send the packet out every port it can because it doesn't have any idea what else to do with. And if it sends it to the router, and the router says, no it has to go back towards you, wouldn't the packet just go in circles for years with the router saying, "its in your direction", and the switching saying "i don't know where this is supposed to go, so i'll send it anywhere i can"
thanks for any help at all. really frustrated.