What is the Spanning Tree election criteria? and what are the STP port states?

Spanning Tree Election Criteria:

-It selects paths according to the following criteria or

1. Lowest root bridge ID (BID)

2. Lowest cost path to the root

3. Lowest sender bridge ID
4. Lowest sender port ID (PID)


Port States

  1. Disable
  2. Blocking
  3. Listening
  4. Learning
  5. Forwarding


Disable: It is considered as non-operational, it will not participate in frame forwarding
Blocking: It will not forward frames or learn MAC Address
Listening: In this state a port may become Root or designated port

Learning: the port is listening for and processing BPDUs .

Forwarding: This port is fully functional, it will send and listen for BPDUs, learn MAC Addresses and Forward Frames, Root and designated Ports will move to Forwarding State.