Spanning Tree (PVST+)

#PVST+ (Per VLAN Spanning Tree Plus) is a Cisco proprietary protocol that extends the IEEE 802.1D Spanning Tree Protocol (STP) by providing a separate spanning tree for each VLAN in a network.

In traditional #stp, all #VLANs in a network share the same spanning tree. However, this can lead to suboptimal network performance because a change in one VLAN can cause the entire network to reconverge. #PVST+ allows each VLAN to have its own independent spanning tree, which improves network performance by allowing traffic for different VLANs to take different paths through the network.

Here the are the most useful command in this #protocol are :

1- (config) ===> show spanning-tree vlan [id] : This command provides details such as the root bridge for the VLAN, the designated and non-designated ports, the port costs and priorities, and the path cost for each port. This information can be very helpful for troubleshooting network issues, identifying potential network loops, and ensuring that the network is properly optimized for performance.

2- (config) ===> show spanning-tree summary : This command provides a summary of the spanning tree protocol for all VLANs configured on the switch, including the total number of VLANs, the number of active and blocked ports, and the status of the root bridge.

3- (config) ===> clear spanning-tree : This command can be useful for resetting the spanning tree protocol on a switch or for clearing any configuration errors or inconsistencies that may be causing network issues. However, this command should be used with caution as it can potentially disrupt network traffic.

4- (config) ===> spanning-tree priority : This command is used to set the bridge priority for a switch in a Spanning Tree Protocol (STP) network. The bridge priority is a value that determines which switch will become the root bridge for the STP network. By default, all switches in an STP network have a bridge priority of 32768, and the switch with the lowest bridge priority becomes the root bridge. However, administrators can use the "spanning-tree priority" command to manually set the bridge priority for a switch, which can be useful for controlling the topology of the network.

#SpanningTree #cisco #switching #ieee #stp