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What is the minimum bridge priority of a switch?
root bridge
Every switch taking part in spanning tree has a bridge priority. The switch with the lowest priority becomes the root bridge. If there’s a tie, then the switch with the lowest bridge ID number wins.
What three information must match for MST to form a single region?
It’s possible to have one or more regions and here are the attributes that need to match: MST configuration name. MST configuration revision number. MST instance to VLAN mapping table.
Why is default bridge priority 32768?
The default is 32768. The lower the number the more likely the switch will be chosen as the root switch. Valid priority values are multiples of 4096. Spanning-tree priority xxx configures the priority in RSTP if RSTP is running, or configures the CIST priority if MSTP is running.
What is the main purpose of MST?
Multiple Spanning Tree (MST) was created to allow for multiple spanning tree topologies while preserving scalability. MST enables an administrator to map an arbitrary number of VLANs to a single MST instance, resulting in the minimum number of instances needed to satisfy a design.
What is a MST region?
A group of switches that collectively define multiple Spanning Tree instances is known as an MSTP Region.. Each switch can belong to only one region. Switches belong to the same MSTP region if they share the same configuration attributes: * MST Config Name (32 bytes, Example MST Configuration.
What is the default priority in STP?
32768
The priority range is 0 to 61440 in increments of 4096. The default is 32768. The lower the number the more likely the switch will be chosen as the root switch.
How do I set priority in STP?
To ensure that a switch has the lowest bridge priority value, use the spanning-tree vlan vlan-id root primary command in global configuration mode. The priority for the switch is set to the predefined value of 24,576 or to the highest multiple of 4096 less than the lowest bridge priority detected on the network.
How are CST, ist, cist and MST related?
An MST instance is local to the region; for example, MST instance 1 in region A is independent of MST instance 1 in region B, even if regions A and B are interconnected. A CIST is a collection of the ISTs in each MST region. The CST interconnects the MST regions and single spanning trees.
Which is an instance of a CST in a bridged network?
For 802.1q, a bridged network only implements a single spanning tree (CST). The IST instance is simply an RSTP instance that extends the CST inside the MST region. The IST instance receives and sends BPDUs to the CST. The IST can represent the entire MST region as a CST virtual bridge to the outside world.
Which is spanning tree runs in an MST region?
Unlike other spanning tree protocols, in which all the spanning tree instances are independent, MST establishes and maintains IST, CIST, and CST spanning trees: An IST is the spanning tree that runs in an MST region.
What do you need to know about MST Configuration?
The MST configuration controls the MST region to which each device belongs. The configuration includes the name of the region, the revision number, and the VLAN-to-MST instance assignment mapping. A region can have one or multiple members with the same MST configuration.