Detailed description of Spanning Tree Protocol-switch port status under STP

If each port on a vswitch has a host. So without listening and learning, it is easy to cause a broadcast storm. The Spanning Tree Protocol STP is generated to solve such problems.

How the Spanning Tree works:

The international standard for Spanning Tree Protocol is 802.1b. the Network Bridge/switch that runs the Spanning Tree Algorithm communicates configuration information with other switches through the Network Bridge Protocol Data Unit BPDU within the specified interval of 2 seconds by default. The process is as follows:

◆ Select only one root bridge in the given broadcast domain of the root bridge by comparing the priority of the bridge ).

◆ The remaining non-root bridges only have one port leading to the root switch, which is called the root port.

◆ Each CIDR block has only one forwarding port.

◆ All connection ports of the root switch are forwarding ports.

Note: The Spanning Tree Protocol is generally enabled on the switch by default, and can work normally without manual intervention. However, this automatic generation scheme may cause the data transmission path to be not optimized. Therefore, you can manually set the bridge priority to influence the generation result of the Spanning Tree.

Status of the Spanning Tree:

The port on the switch that runs the Spanning Tree Protocol is always in the following four States. During normal operation, the port is in the forwarding or blocking status. When the device identifies a change in the network topology, the switch automatically changes the status. During this period, the port is currently in the listening and learning status.

Blocking: all ports are started in blocking status to prevent loops. The spanning tree determines which port is switched to the forwarding state. The blocked port does not forward data but can accept BPDU.

Listener: Do not send and receive data, receive and send bpdu, do not learn the temporary status of the address ).

Learning: do not receive or forward data, receive and send bpdu, and start to learn the temporary status of the MAC address table ).

Forward: the port can forward and accept data.

1. Spanning Tree Protocol learning key points full record
2. Understanding the topology changes of the Spanning Tree Protocol