spanning tree protocol Archives

How to Troubleshoot Spanning-Tree Protocol

Posted on October 31, 2019 by Asad Ijaz

In most networks, the best Spanning-Tree Protocol topology is determined as part of the network blueprint. The Spanning-Tree Protocol is implemented by configuring Spanning-Tree Protocol priority and cost values. Several things could go wrong. You can expect something, but your switches can give you something different. Situations also occur when the Spanning-Tree Protocol was not… Read more

How to Configure Spanning-Tree Mode – Rapid PVST+

Posted on October 30, 2019 by Asad Ijaz

The default configuration of the spanning-tree protocol (STP) on a Catalyst 2960 Series switch is PVST+. A Catalyst 2960 series switches support PVST+, Rapid PVST+, and MST, but only one version can be active for all VLANs. Rapid PVST+ is the Cisco execution of RSTP supporting RSTP on a per-VLAN basis. We can control the… Read more

Network diagram showing spanning tree configuration with bridge IDs and VLANs

How to Configure Spanning-Tree Bridge ID – Briefly Explained

Posted on October 27, 2019 by Asad Ijaz

When configuring a specific switch as a Root Bridge, the bridge ID priority value must be adjusted to be lower than the bridge priority values of all the other switches on the network. There are two different methods for configuring the bridge priority value on a Cisco Catalyst switch. Method 1 To ensure the switch… Read more

802.1D Bridge Protocol Data Unit (BPDU) Frame Format

Posted on October 22, 2019 by Asad Ijaz 2 Comments

The spanning tree algorithm exchanges the Bridge Protocol Data Unit (BPDU) to elect the Root Bridge. It is a frame containing 12 different fields with different information. The information in the BPDU is used to determine the root bridge and the paths to the root bridge. The figure below illustrates the Bridge Protocol Data Unit… Read more

Network diagram with switches, root bridge priority settings, and STP port roles (root, designated, blocked) labeled for clarity.

Spanning Tree – Root Bridge

Posted on October 18, 2019 by Asad Ijaz 5 Comments

Every spanning tree switched network or broadcast domain has a switch designated as the root bridge. It serves as the reference point for all spanning-tree-enabled switches. The spanning tree algorithm determines which redundant paths to block. It is selected as an election process. The figure below illustrates the bridge ID (BID) fields. BID is a… Read more

What is Spanning Tree Protocol

Posted on October 17, 2019 by Asad Ijaz 5 Comments

In the previous article, I have explained the redundancy. It increases the network availability by protecting the network from a single point of failure, such as a fault in a network cable or fault in a switch. When engineers introduce physical redundancy in design, loops and duplicate frames happen. I have written in the previous… Read more