Contents
What is TCN Bpdu?
Message Type (Configuration or TCN BPDU) 1. A topology change occurs when a switch either moves a port into the Forwarding state or moves a port from the Forwarding or Learning states into the Blocking state. In other words, a port on an active switch comes up or goes down.
What is the first thing that determines if a switch is the root bridge?
An election process determines which switch becomes the root bridge. Each switch has a Bridge ID (BID) that is made up of a priority value, an extended system ID, and the MAC address of the switch. All switches in the network take part in the election process.
Do all switches send Bpdu?
All the switches in network intially sends and receives BPDU messages when connected in network and election process starts .
What is STP topology?
The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. RSTP was designed to be backwards-compatible with standard STP.
How does a BPDU lead to a root bridge?
When a port receives a BPDU, it has a path to the Root Bridge (Root Switch), because BPDU s are originated from the Root Bridge (Root Switch). The port which receives a BPDU is normally a Root Port. For a Non-Root Bridge a port that receives a BPDU, that port leads to the Root Bridge (Root Switch).
How is BPDU generated and how does BPDU work?
After the Root Bridge (Root Switch) has been identified, all other Non-Root Switches bridges do not actually generate Configuration BPDUs. Non-Root Switch only propagates the BPDU s generated by the Root Bridge (Root Switch) .
When does a link go down, the switch generates a TCN?
When a link goes down / comes up, the switch generates TCN and send it on its root port towards the root bridge. all the switches towards the root will relay this towards the root bridge.
Which is the only bridge that does not send BPDUs?
The STA elects a single root bridge in the whole bridged network (per-VLAN). The root bridge sends BPDUs that are more useful than the ones any other bridge sends. The root bridge is the only bridge in the network that does not have a root port. All other bridges receive BPDUs on at least one port.