Foundation Summary

The Foundation Summary is a collection of information that provides a convenient review of many key concepts in this chapter. If you are already comfortable with the topics in this chapter, this summary can help you recall a few details. If you just read this chapter, this review should help solidify some key facts. If you are doing your final preparation before the exam, this information is a convenient way to review the day before the exam.

RSTP port roles:

• Root port

• Designated port

• Alternate port

• Backup port

RSTP port states:

• Discarding

• Learning

• Forwarding

Table 12-3. RSTP Configuration Commands

Task	Command Syntax
Define an edge port	Switch(config-if)# spanning-tree portfast
Override a port type	[View full width] Switch(config-if)# spanning-tree link-type point-to-point

STP instances involved with MST:

• Common Spanning Tree (CST) Used to maintain a single loop-free topology for the entire network

• Internal Spanning Tree (IST) Used like CST, to maintain a single, loop-free topology inside an MST region

• MST instances (MSTIs) Used inside an MST region to maintain loop-free topologies for sets of mapped VLANs

Table 12-4. MST Region Configuration Commands

Task	Command Syntax
Enable MST on a switch	Switch(config)# spanning-tree mode mst
Enter MST configuration mode	Switch(config)# spanning-tree mst configuration
Name the MST region	Switch(config-mst)# name name
Set the configuration revision number	Switch(config-mst)# revision version
Map VLANs to an MST instance	Switch(config-mst)# instance instance-id vlan vlan-list
Confirm new MST configuration changes	Switch(config-mst)# show pending
Commit new MST changes	Switch(config-mst)# exit

Table 12-5. MST Tuning Configuration Commands

Task	Command Syntax
Set the Root Bridge	[View full width] Switch(config)# spanning-tree mst instance-id root {primary | secondary} [diameter diameter]
Set bridge priority	[View full width] Switch(config)# spanning-tree mst instance-id priority bridge- priority
Set port cost	[View full width] Switch(config)# spanning-tree mst instance-id cost cost
Set port priority	[View full width] Switch(config)# spanning-tree mst instance-id port-priority port-priority
Set STP timers	Switch(config)# spanning-tree mst hello-time seconds Switch(config)# spanning-tree mst forward-time seconds Switch(config)# spanning-tree mst max-age seconds