Contents
xxiii
Cisco IE 2000 Switch Software Configuration Guide
OL-25866-01
RFCs 19-7
CHAPTER
20 Configuring STP 20-1
Finding Feature Information 20-1
Prerequisites for Configuring STP 20-1
Restrictions for Configuring STP 20-1
Information About Configuring STP 20-1
STP 20-2
Spanning-Tree Topology and BPDUs 20-2
Bridge ID, Switch Priority, and Extended System ID 20-3
Spanning-Tree Interface States 20-4
Blocking State 20-5
Listening State 20-6
Learning State 20-6
Forwarding State 20-6
Disabled State 20-6
How a Switch or Port Becomes the Root Swit ch or Root Port 20-7
Spanning Tree and Redundant Connectivity 20-7
Spanning-Tree Address Management 20-8
Accelerated Aging to Retain Connectivity 20-8
Spanning-Tree Modes and Protocols 20-9
Supported Spanning-Tree Instances 20-9
Spanning-Tree Interoperability and Backward Compatibility 20-10
STP and IEEE 802.1Q Trunks 20-10
VLAN-Bridge Spanning Tree 20-10
Default Spanning-Tree Settings 20-11
Disabling Spanning Tree 20-11
Root Switch 20-11
Secondary Root Switch 20-12
Port Priority 20-12
Path Cost 20-13
Spanning-Tree Timers 20-13
Spanning-Tree Configuration Guidelines 20-13
How to Configure STP 20-14
Changing the Spanning-Tree Mode 20-14
Configuring the Root Switch 20-15
Configuring a Secondary Root Switch 20-16
Configuring Port Priority 20-16
Configuring Path Cost 20-16