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How does STP determine designated ports?
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.
What is the property of STP root port?
The root port is always in the forwarding state. If the speed/duplex of the port is changed, spanning tree recalculates the path cost automatically. A change in the path cost can change the spanning tree topology.
What is difference between STP and RSTP?
Unlike STP, which has five switchport states, RSTP has only three: discarding, learning, and forwarding….Comparing STP and RSTP Port States.
| STP | RSTP |
|---|---|
| Blocking | Discarding |
| Listening | Discarding |
| Learning | Learning |
| Forwarding | Forwarding |
How do I know if a port is non designated?
Select the port on the Switch on the network segment (which does not include a Root Port) with the lowest accumulated Spanning Tree Path Cost to the Spanning Root Bridge (Root Switch) as the Designated Port and other side of the Designated Port will be the Non-Designated Port.
What happens when the switch receives a superior BPDU?
According to the spanning tree doc: after the switch receives a superior BPDU. Root guard puts the port in the root-inconsistent STP state. No traffic passes through the port in this state. After device D ceases to send superior BPDUs, the port is unblocked again.
Which is the root port of SW2 for BPDU?
SW2 has E0/0 as as root port towards SW1. The cost of links has been modified to make it easy to change the forwarding path. Now to remove the cost on the E0/0 interface of SW3 and E0/1 interface of SW2. This should make SW3 send a better BPDU making SW2 change its root port.
Which is the designated port, root bridge or designated port?
The designated ports are the ports responsible for forwarding traffic onto a network segment. Think of it like this -. RPs lead toward the root bridge. DPs lead away from the root bridge. because the root bridge has no blocking ports all it’s ports are DP’s.
Can a designated port be an access port?
Access ports are probably going to be in the forwarding state, and in reality you should probably have the spanning-tree portfast command on those ports so that they do not cycle through the stages of STP, better for them to go straight to forwarding. The designated port should never be an access port.