07-05-2022 04:10 AM
On production environment
Why it is important do determine the designated port?
Thanks
07-05-2022 05:31 AM - edited 07-05-2022 08:21 AM
Hello,
In my opinion I wouldn't just single out Designated ports. I would place importance on learning and understanding all the ports as that's how you determine traffic flow in an STP topology. But to answer your question Designated ports are important because they are all ports from the Root bridge to downstream devices and how traffic from the Root bridge gets to these devices. You also need to know all ports states so when your devices have an STP convergence (which also shouldn't be often or at all) then you know how the traffic will flow once the network has converged.
By definition :
Designated port—A designated port is a non-root port that is permitted to forward traffic. Designated ports are selected on a per-segment basis, based on the cost of each port on either side of the segment and the total cost calculated by STP for that port to get back to the root bridge. If one end of a segment is a root port, then the other end is a designated port. All ports on the root bridge are designated ports.
Hope that helps
-David
07-05-2022 12:26 PM
Thanks,
The downstream can help to rlaborate
07-05-2022 12:42 PM
07-05-2022 08:15 AM - edited 07-05-2022 08:15 AM
two point
*1*
some STP feature work only in Designated Port or in SW with Designated port
*2*
if you see SW other than your topology design ROOT have all port as designated port then this first indication that your topology know have two root / face before elect new root / or the config is wrong.
07-05-2022 12:25 PM
Thanks,
can you mention STP feature that works only in designated port?
07-05-2022 02:32 PM - edited 07-05-2022 04:09 PM
Different between Designated port and non designated port
Designated port send bpdu
Non designated port receive bpdu
So feature like bpdu guard must config in designated port.
NOTE:- BPDU guard need more criteria to apply which is port must connect to Host not to other SW.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide