hub to a switch silly question

[Alex16]

I am a noob... But you won't be waisting your time giving me an answer. The question is on hypothetical situation but I really need to know.
Q is: if I have a hub (4 port) where two of its ports are connected together with a cross over cable. Third port is connected to a switch and the last one has a pc on it. Now, How an stp on a switch will treat such a set up? Will the hub loop BPDUs coming from the switch forcing it to block the switch port?


Thank you!

 

[helpdeskdan]

NO! No, no, no, no, no! Do not ever do "two of its ports are connected together with a cross over cable!" Not unless you want to have major collision problems in your network! STP doesn't work on hubs - just set the port to portfast after you pull that crossover cable off. Also, do a show interface to make sure it's set to half duplex.

Now, if you are just doing this for fun (which I hope you are) the switch will NOT recieve it's own BPDU's. It will just receive collisions as it tries to send it's traffic.

If you were using a 4 port unmanaged switch.... well, you'd have a bridging loop and that would create problems that would hose your switch long before STP could realize what to do about it.

 

[Alex16]

thanks!!! Sure it is just thought experiment. Me and my buddy had an argument of what would happened if this was done. Thanks for your answer. I ws just thinking that switch port would somehow know it's getting back it's own BPDUs and ignore it.

thank you!

 

[helpdeskdan]

Man, you had me worried for nothing. ;-)