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Zorluk: OrtaSTP Port States and PortFast Benefits

A switch port running classic IEEE 802.1D Spanning Tree Protocol (STP) detects link UP on a non-PortFast access interface. Place the 802.1D STP port states in the exact chronological sequence through which the interface transitions from link initialization to fully active frame processing.

  1. 1Blocking State
  2. 2Listening State
  3. 3Learning State
  4. 4Forwarding State

Cevap

The correct operational sequence of classic 802.1D STP port states from link bring-up to active data transmission is: Blocking State -> Listening State -> Learning State -> Forwarding State.
Under standard IEEE 802.1D Spanning Tree Protocol, non-PortFast interfaces progress strictly through Blocking, Listening, Learning, and Forwarding states. The Blocking state prevents loops upon initialization; Listening (15s Forward Delay) processes BPDUs and determines port roles; Learning (15s Forward Delay) builds MAC address tables from source MACs; and Forwarding permits normal data payload processing.

Adım Adım Çözüm

1
Identify the initial non-functional state upon physical link activation.
The port initializes in the Blocking State.
STP ports default to Blocking to discard user data frames and prevent switching loops while listening for control frames (BPDUs).
2
Identify the state where STP role determination occurs.
The port moves into the Listening State.
During the Listening phase (lasting 15 seconds by default), the switch processes and sends BPDUs to determine Root Bridge and port roles without populating MAC tables or forwarding data frames.
3
Identify the state where address table construction begins.
The port transitions to the Learning State.
After the first 15-second Forward Delay timer expires, the port enters Learning where it examines source MAC addresses of incoming frames to build the MAC address table, but still drops payload data frames.
4
Identify the final fully functional state.
The port enters the Forwarding State.
After the second 15-second Forward Delay timer expires (total 30 seconds convergence), the port transitions to Forwarding where it actively forwards and receives user data frames.

Anahtar Kavram

IEEE 802.1D STP Sequential Port State Transitions
Tahmini Süre:1m 15s
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Konular

STP Port States and PortFast Benefits

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