Confusion on STP, root port and designated port

[kelvinwgr]

Hi can someone explain to me in lag man term what is the difference between a root port, root switch, designated port and designated switch.

Sometimes I also come across root bridge. I am confused over all these. Can somebody enlighten me? Thanks

[ciscok1d]

It takes time to get used to the terminology, it can be confusing.

This video explains most if not all the STP terms you mentioned and gives a good overview of the STP protocol.

http://www.youtube.com/watch?v=ihF_78oIaDI

Also Root Switch = Root Bridge = Designated Switch. They are different names for the same thing.


The Root Bridge/Switch is the Main Switch in the STP Topology, chosen by election.
A designated port is one that is active and forwarding traffic.
A Blocked port is one that is not active or forwarding traffic.
A Root Port is an active port that leads to the Root Bridge.

A designated port is either connected to a Root Port or a Blocked Port.
A Root Port is either connected to the Root Bridge or to another designated port but never a blocked port.
All ports on the Root Bridge/Switch are Designated ports by default as there are no blocking ports on a Root Bridge

HTH

[kelvinwgr]

Hi ciscok1d,

Thanks for the precise and straight forward explanation. I had a hard time reading the chunks of paragraphs explained on other websites.

I am taking my ccna exam 640-802 next week, so it's better if I can clarify these confusion.  =)