Spanning Tree States Explained in Packet Tracer Lab || in Tamil || Dinesh Kumar M

#CCNA#STP#PacketTracer
STP port states
All ports on a STP running switch, go through the four different states; blocking, listening, learning, and forwarding. Through these states, the switch not only understands the network topology but also calculates the path cost value and based on that value elects the designated and non-designated ports. After these states, the switch is considered as the STP convergent switch. Let’s understand each state in detail.
STP Blocking state
When we power on a switch, the switch puts all of its ports in this state. In this state, the switch only listens and processes the BPDUs. Except the BPDUs, it drops all other frames. From the incoming BPDUs, it learns the network topology and determines the ports which will work as the root ports, as the designated ports, and as the blocked ports.
All ports remain in this state for twenty seconds. After twenty seconds, only the root port and designated ports move into the next state. The remaining ports stay in this state.
STP Listening state
In this state, ports still listen and process only BPDUs. All other frames except BPDUs are dropped. The switch double-checks the layer 2 topologies to make sure that no loops occur in the network before processing the data frames. Ports remain in this state for fifteen seconds.
STP Learning state
Only the root port and designated ports enter into the learning state from the listening state. In this state, ports still listen and process BPDUs. However, in this state, ports start processing user frames. Switch examines the source address of user frames and updates its CAM table but it does not forward any user frame to the destination port. Ports stay in this state for fifteen seconds.
STP Forwarding state
In this state, the switch listens and processes both BPDUs and user frames. It uses BPDUs to monitor the network topology. By reading the source address field of users’ frames it also builds and updates CAM table entries. This state is also referred as the convergence.
Convergence refers to a situation in which all ports of a switch have transitioned to either forwarding or blocking mode. During the STP converging, the switch does not forward any user frame. Usually, convergence takes place in fifty seconds (20 seconds of the blocking state + 15 seconds of the listing state + 15 seconds of the learning state).
STP Disable state
This state applies to all ports which are either manually shut down or removed from the STP by an administrator. All unplugged ports also remain in this state. Any port which belongs to this state does not participate in the STP operation.
STP operation in nutshell
All switches of the STP domain, first elect a root bridge. The root bridge acts as a point of reference for all other switches in the network. All ports of the root bridge remain in the forwarding mode.
Once the root bridge is elected, all remaining switches select a single port that has the shortest path cost to reach the root bridge and marked it as the root port.
After selecting the root port, switches determine a single designated port for each connection.
If multiple ports are connected with the same switch or LAN segment, the switch select only one port that has the lowest path cost and marks it as the designated port.
Once the root port and designated ports are selected, the switch blocks all remaining ports to remove any possible or existing loop from the network.
STP variations
There are two different implementations of the STP protocol, DEC and 802.1d. Both implementations are not compatible with each other. When you purchase a new switch for the network, make sure it supports the same variation of the STP which your existing switches are using. Never mix the devices which are running 802.1d’s STP with the devices which are running DEC’s STP, otherwise, you might run into the layer 2 looping problems. All of Cisco’s switches use 802.1d’s STP.

[@networksecurity778]

Bro your videos really useful bro..naan ஆதாங்கத்துல பேசிட்டன்...உங்க lecturing superb..but சின்ன சின்ன இந்த விசயத்துல பிழ விடாதீங்க

[@DineshkumarPalani]

Sure bro I know your feeling Atleast neengalavathu pathu sonningala no one noticed this.. sure I will re upload with good voice..

[@DineshkumarPalani]

Bro still stuck up with work not able to post any videos and also my personal laptop got some issue, soon I will try to continue posting the videos don’t get disappointed..

[@networksecurity778]

@@DineshkumarPalani thanks bro

[@vickyvignesh2953]

Voice ketkala

[@DineshkumarPalani]

Yes editing problem.most of the videos have voice issue .

[@msd7001]

@@DineshkumarPalaniபபழஜஜ.

[@lajinijivideos7280]

👌👌👌

[@vijayv2879]

Bro voice kekkave Ella

[@DineshkumarPalani]

Yes bro voice problem..