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How do I check my priority bridge?
To verify the bridge priority of a switch, use the show spanning-tree command. In Example 3-4, the priority of the switch has been set to 24,576. Also notice that the switch is designated as the root bridge for the spanning-tree instance.
What is designated bridge in STP?
When more than one bridge on a segment leads to a least-cost path to the root, the bridge with the lower bridge ID is used to forward messages to the root. The port attaching that bridge to the network segment is the designated port for the segment.
How do you find the root bridge in STP?
In order to identify which MS switch is the Root Bridge, navigate to Switch > Monitor > Switches and select the desired switch. In the switch status area, take note of the field called RSTP Root as it will identify which switch is the Root Bridge.
What are the default STP bridge priority?
32768
The default priority is 32768, and additional roots are set below this number. STP increments priority by 4096, so the next priority is 4096 below 32768. The lower the number, the higher the priority.
Why is my Cisco Catalyst not performing STP?
BPDUs can be corrupted along the path from one bridge to the other, which also prevents proper STP behavior. Aside from the forwarding loops, when no ports are blocked, there are situations when only certain packets are incorrectly forwarded through the blocking ports. In most cases, this is caused by software issues.
How is the root port selected in a spanning tree?
Spanning tree selects the root port based on the path cost. The port with the lowest path cost to the root bridge becomes the root port. The root port is always in the forwarding state. If the speed/duplex of the port is changed, spanning tree recalculates the path cost automatically.
When do you need a root bridge in a switching network?
When you implement a root bridge in a switching network, you usually refer to the root bridge as the root switch. Each VLAN must have its own root bridge because each VLAN is a separate broadcast domain. The roots for the different VLANs can all reside in a single switch or in various switches.
How is a forwarding loop related to a STP?
A forwarding loop (such as an STP loop) occurs when no port in a redundant topology is blocked, and traffic is forwarded in circles indefinitely. Once the forwarding loop starts, it will likely congest the lowest-bandwidth links along its path—if all the links are of the same bandwidth, all links will likely be congested.