STP (04)

STP에서 포트가 가질수 있는 상태

 

• Root/Designated ports remain stable in a Forwarding state (네트워크의 구조에 변화가 없는 한...)
• Non-Designated ports remain stable in a Blocking state. (네트워크의 구조에 변화가 없는 한...)
• Listening and Learning are transitional states which are passed through when an interface is activated, or when a Blocking port must transition to a Forwarding state due to a change in the network topology.

• Non-Designated ports are in a Blocking state.
• Interfaces in a Blocking state are effectively disabled to prevent loops.
• Interfaces in a Blocking state do not send / receive regular network traffic.
• Interfaces in a Blocking state receive STP BPDUs.
• Interfaces in a Blocking state do NOT forward STP BPDUs.
• Interfaces in a Blocking state do NOT learn MAC addresses.

• After the Blocking state, interfaces with the Designated or Root role enter the Listening state.
• Only Designated or Root ports enter the Listening state (Non-designated ports are always Blocking).
• The Listening state is 15 seconds long by default. This is determined by the Forward delay timer.
• An interface in the Listening state ONLY forwards/receives STP BPDUs.
• An interface in the Listening state does NOT send/receive regular traffic.
• An interface in the Lisetning state does NOT learn MAC addresses from regular traffic that arrives on the interface.

• After the Listening state, a Designated or Root port will enter the Learning state.
• The Learning State is 15 seconds long by default. This is determined by the Forward delay timer (the same timer is used for both the Listening and Learning states).
• An interface in the Learning state ONLY sends/receives STP BPDUs.
• An interface in the Learning state does NOT send/receive regular traffic.
• An interface in the Learning state learns MAC addresses from regular traffic that arrives on the interface.

• Root and Designated ports are in a Forwarding state.
• A port in the Forwarding state operate as normal.
• A port in the Forwarding state sends/receives BPDUs.
• A port in the Forwarding state sends/receives normal traffic.
• A port in the Forwarding state learns MAC addresses.