Which switch is root bridge??
Switch1 is root bridge.
SW-2 port is blocked thats corrct. see how SW-2 is blocked.
here SW-1 is root bride right.
2nd step is we will check the cost to root bridge. Higher cost will lose the election
SW-0 cost to root bridge is 19 , SW-3 cost to root bride is also 19 and
SW-2 cost to root bride is 38 from both ports.
so here sw-2 will lose the election and sw-2 one port will be blocked.
3rd step is sw-2 which port will be blocked ?
we will check the senders switch mac address
for SW-2 , SW-0 and SW-3 are senders switch, we will compare the SW-0 & SW-3 mac address
here SW-2 lose the election and and SW-2 port Will be blocked which is going towards SW-3. (f0/2 port).
This is how STP block the port.
Hope this reply clear your doubt. Please correct me if i am wrong…!!!