Switch 3 runs Rapid Per-VLAN Spanning Tree Plus (RPVST+), which is enabled on VLANs 1-4.
Select the correct number for each of these parameters.
Explanation:
Spanning Tree instances – 4
RPVST+ BPDU transmitted – 4Rapid PVST+ is the IEEE 802.1w (RSTP) standard
implemented per VLAN. A single instance of STP runs on each configured VLAN (if you do not
manually disable STP). Each Rapid PVST+ instance on a VLAN has a single root switch. You can
enable and disable STP on a per-VLAN basis when you are running Rapid PVST+.
When a switch transmits a Rapid PVST+ BPDU frame, all switches connected to the VLAN on
which the frame is transmitted receive the BPDU. When a switch receives a BPDU, it does not
forward the frame but instead uses the information in the frame to calculate a BPDU, and, if the
topology changes, initiate a BPDU transmission.
A BPDU exchange results in the following:
•
One switch is elected as the root bridge.
•
The shortest distance to the root bridge is calculated for each switch based on the path cost.
•
A designated bridge for each LAN segment is selected. This is the switch closest to the root bridge
through which frames are forwarded to the root.
•
A root port is selected. This is the port providing the best path from the bridge to the root bridge.
•
Ports included in the spanning tree are selected.
See the “Rapid PVST+ BPDUs” section for a information about the fields that Rapid PVST+ adds to the BPDU.