Information About Mst - Cisco AJ732A - MDS 9134 Fabric Switch Configuration Manual

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Configuring MST
Multiple Spanning Tree (MST), which is the IEEE 802.1s standard, allows you to assign two or more
VLANs to a spanning tree instance. MST is not the default spanning tree mode; Rapid per VLAN
Spanning Tree (Rapid PVST+) is the default mode. MST instances with the same name, revision number,
and VLAN-to-instance mapping combine to form an MST region. The MST region appears as a single
bridge to spanning tree configurations outside the region. MST fails over to IEEE 802.1D Spanning Tree
Protocol (STP) when it receives an 802.1D message from a neighboring switch.
Note Spanning tree is used to refer to IEEE 802.1w and IEEE 802.1s. If the text is discussing the IEEE 802.1D
Spanning Tree Protocol, 802.1D is stated specifically.
This chapter includes the following sections:
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Note See
Chapter 10, "Configuring STP Extensions"

Information About MST

This section includes the following topics:
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OL-16597-01
Information About MST, page 9-1
Configuring MST, page 9-9
Chapter 8, "Configuring Rapid PVST+"
MST Overview, page 9-2
MST Regions, page 9-2
MST BPDUs, page 9-3
MST Configuration Information, page 9-3
IST, CIST, and CST, page 9-4
Hop Count, page 9-7
Boundary Ports, page 9-7
Detecting Unidirectional Link Failure, page 9-8
Port Cost and Port Priority, page 9-8
Interoperability with IEEE 802.1D, page 9-9
C H A P T E R
for complete information on STP and Rapid PVST+ and
for complete information on STP extensions.
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
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9-1