How do you elect root bridge in STP the process?
The root bridge is selected by manually configuring its bridge priority to a low value. 32768 is the default value out of a range from 0 to 61440. If all switches in a single spanning tree have the same bridge priority, the switch with the lowest MAC address will become the root bridge.
How does STP elect root port?
STP Root Port Selection
- Lowest bridge ID (Priority:MAC Address) switch becomes the Root-Bridge.
- Each non-root bridge should have ONE root port (RP) which is the port having lowest path-cost to Root Bridge.
- All ports in Root Bridge become Designated Ports (DP)
- Each segment should have one Designated Port (DP)
How is a switch elected as a root bridge for spanning tree if the bridge priorities are the same?
How is a switch elected as a root bridge for spanning tree if the bridge priorities are the same? The switch with the lowest IP address will become the root bridge. The switch with the lowest MAC address will become the root bridge. The switch with the highest IP address will become the root bridge.
What is root path cost in STP?
Path cost – The path cost is the metric stp uses to calculate the shortest path to elect root port to reach the root-bridge . The path cost is based on the speed of the interface of switch .
Which is the root bridge in spanning tree?
Bridge Priority – It is priority, which is assigned to every switch, 32768 by default. Root Bridge – The root bridge is the bridge with lowest Bridge I’d. All the decisions like which ports are the root ports (the port with best path to the root bridge) are made from the perspective of root bridge.
When does a switch become a root bridge?
As all the switches have default priority therefore there is a tie on the basis of priority. Now, the switch with the lowest Mac address will become a root bridge. Here, switch A will become the root bridge as it has the lowest Mac address. Therefore, the ports of switch A will be in forwarding state i.e designated port.
How does the Spanning Tree Protocol ( STP ) work?
As the name implies, STP computes a tree that spans all switches in a network. All switches communicate using Bridge Protocol Data Units (BPDU) with each other.
What does BPDU stand for in spanning tree?
Bridge Priority Data Unit (BPDU) – It contains the Bridge I’d, Sender’s Bridge I’d, Cost to the Root Bridge, Timer values on Root Bridge. All switches exchange BPDU in order to elect root bridge.