2, TCN bpdus contains what content?
Our teacher said TCN BPDU is sub-optimal bpdus, namely exchange himself as the root bridge after receive a less than configuration bpdus sent outside of bpdus,
But I saw on the Internet, some say, out of the type field in the TCN bpdus in other content is empty,
3, TCN bpdus sent up through the root port only?
That shown in the figure below (image do not go up, you make do with see
), three switches connect ring, SW1 is the root bridge, When SW1 and SW2 in the middle of the line after the break, SW2 detected topology change, if it can only send the TCN bpdus from the root port, is not the root bridge forever also can not accept?
My understanding is that of from SW2 SW3 bpdus, 20 seconds to hold time, after your send the TCN bpdus to SW1 (bridge),
4, a direct link to convergence need 50 s: 20 s hold time + 30 s LISTEN/learning,
I want to ask the 20 s of hold time is what? SW2 is not receive configuration bpdus, needs to wait for 20 seconds to send bpdus? After subprime or SW3 received bpdus needs to wait for 20 seconds to enter the listening state?
SW1
SW2 SW3
CodePudding user response:
4, a direct link to convergence need 50 s: 20 s hold time + 30 s LISTEN/learning,I want to ask the 20 s of hold time is what? SW2 is not receive configuration bpdus, needs to wait for 20 seconds to send bpdus? After subprime or SW3 received bpdus needs to wait for 20 seconds to enter the listening state?
CodePudding user response:
great god?CodePudding user response:
Need to wait for 20 seconds