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kian_hong2000 · Joined: 08 Nov 2006 Posts: 8

I am confuse with the term designated and root port.

"The designated port is the port that is the single interface to forward traffic to the root bridge"

"The root port represent a switch's lowest-cost path to the root bridge"

1) Can i say all ports from root bridge port are root ports since they are the lowest-cost path to the root bridge?

2) Say Switch A is the root bridge and Switch B and C is connected through port 1 to Switch A. Can i say port 1 of Switch B and C is a designated port since it is the single interface to forward to the root bridge?

3) Can the root bridge have designated port?

bitgod · Joined: 13 Nov 2007 Posts: 9

This confuses a lot of people. The best way to simplify it is think of inbound to your root bridge and outbound to your distribution. One port on your designated bridge will be a root port, the port with the lowest cost path to the root bridge. Any port on the designated bridge that connects to another bridge even further from the root bridge will be a designated port. A root bridge has nothing but designated ports. There are a lot of good articles on spanning tree out there. It can be a pretty nasty thing to troubleshoot in a large network. *shiver*

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