CCNP ENCOR Chapter 3: Advanced STP Tuning Summary

Chapter 3: Advanced STP
Tuning
Instructor Materials



CCNP Enterprise: Core Networking

,Chapter 3 Content

This chapter covers the following content:

• STP Topology Tuning - This section explains some of the options for modifying
the root bridge location or moving blocking ports to designated ports.

• Additional STP Protection Mechanisms - This section examines protection

mechanisms such as root guard, BPDU guard, and STP loop guard.




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,STP Topology Tuning
• In a properly designed network a switch is deliberately selected to become the root
bridge and the designated and alternate ports are modified.
• Network design considerations factor in hardware platform, resiliency, and network
topology.




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, STP Topology Tuning
Root Bridge Placement
To ensure root bridge placement set the system priority on:
• The root bridge to the lowest value
• The secondary root bridge to a value slightly higher than that of the root bridge
• All other switches to a value higher than the secondary root bridge

Command Description
spanning-tree vlan vlan-id priority priority The priority is a value between 0 and 61,440, in
increments of 4,096.

spanning-tree vlan vlan-id root {primary | The primary keyword sets the priority to 24,576,
secondary} [diameter diameter] and the secondary keyword sets the priority to
28,672. The optional diameter command makes it
possible to tune the Spanning Tree Protocol (STP)
convergence and modifies the timers.

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