Siemens S323, S223 user manual Port States, Listening, Learning, Forwarding, Disabled

UMN:CLI	User Manual
	SURPASS hiD 6615 S223/S323 R1.5

Port States

Each port on a switch can be in one of five states.

	Listening
BPDUs or timeout indicate		Forwarding timer
Potential to become active	BPDUs indicate port	expired
	should not be active
Blocking	BPDUs indicate port	Learning
	should not be active

Forwarding timer

BPDUs indicate portexpired should not be active

Forwarding

Disabled

Fig. 8.13 Port State

•Blocking

a port that is enabled, but that is neither a Designated port nor a Root port, will be in the blocking state. A blocking port will not receive or forward data frames, nor will it transmit BPDUs, but instead it will listen for other’s BPDUs to determine if and when the port should consider becoming active in the spanning tree.

•Listening

the port is still not forwarding data traffic, but is listening to BPDUs in order to compute the spanning tree. The port is comparing its own information (path cost, Bridge Identifier, Port Identifier) with information received from other candidates and deciding which is best suited for inclusion in the spanning tree.

•Learning

the port is preparing to forward data traffic. The port waits for a period of time to build its MAC address table before actually forwarding data traffic. This time is the forwarding delay.

•Forwarding

After some time learning address, it is allowed to forward data frame. This is the steady state for a switch port in the active spanning tree.

•Disabled

When disabled, a port will neither receive nor transmit data or BPDUs. A port is in this state because it is broken or disabled by administrator.

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