From the course: CCNP Switching (300-115) Cert Prep: 1 Layer 2 Technologies
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STP Config: Root selection - Cisco Switches Tutorial
From the course: CCNP Switching (300-115) Cert Prep: 1 Layer 2 Technologies
STP Config: Root selection
- [Lecturer] Spanning-tree configuration is another one of the key topics covered in the switching exam. And for good reason. Though it is generally a set it and forget it protocol, it's important to understand how to implement changes to affect traffic control and not just initial configuration. Cisco switches generally default to PVST+. To view the configured mode, I enter "show spanning-tree" and it will generate a lot of output but in particular it will show spanning-tree enabled protocol mode, where mode is the configured protocol. If it shows the mode as IEEE, it is in fact configured for PVST+ which is not the IEEE standard but is Cisco's standard. To globally disable a spanning-tree for a VLAN, which is not recommended, I enter the no spanning-tree vlan command from global configuration mode. Cisco also says that spanning-tree can be disabled for a specific vlan on an interface. But an administrator should exercise caution when attempting the no spanning-tree vlan interface…