Maybe this is stupid question. But I really need you help. Please see attachment. Can computer A talks to computer B? If yes or no, please give explanation. Thanks.
Absolutely A should be able to talk to B. This question confuses many people, but if the link between Sw1 and Sw2 is NOT a trunk, then A can talk to B.
Why? Okay, when A wants to talk to B it does a calculation and finds that B is on the same subnet. So, A would then ARP for B. The ARP comes into SW1 on Vlan8, thus SW1 would broadcast the ARP out all interfaces in Vlan8 (including the connection to SW2 if it is not a trunk, thus untagged). So, then the ARP comes into Vlan9 in SW2 (keep in mind it is not tagged since this is an access link). SW2 will then broadcast the ARP to all interfaces in Vlan9, which would include computer B. The reply would flow in a similar fashion.
See the attachment. Hope this helps,