Overview Of Mst - Cisco 4500M Software Manual

Understanding and Configuring Multiple
Spanning Trees
This chapter describes how to configure the IEEE 802.1s Multiple Spanning Tree (MST) protocol on the
Catalyst 4500 series switch. MST is a new IEEE standard derived from Cisco's proprietary
Multi-Instance Spanning-Tree Protocol (MISTP) implementation. With MST, you can map a single
spanning-tree instance to several VLANs.
This chapter includes the following major sections:
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For complete syntax and usage information for the switch commands used in this chapter, refer to the
Note
Catalyst 4500 Series Switch Cisco IOS Command Reference and related publications at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/index.htm.

Overview of MST

The following sections describe how MST works on a Catalyst 4500 series switch:
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OL-6696-01
Overview of MST, page 16-1
MST Configuration Restrictions and Guidelines, page 16-8
Configuring MST, page 16-9
IEEE 802.1s MST, page 16-2
IEEE 802.1w RSTP, page 16-3
MST-to-SST Interoperability, page 16-4
Common Spanning Tree, page 16-5
MST Instances, page 16-5
MST Configuration Parameters, page 16-5
MST Regions, page 16-6
Message Age and Hop Count, page 16-7
MST-to-PVST+ Interoperability, page 16-8
C H A P T E R
Software Configuration Guide—Release 12.2(25)EW
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