CISCO - Spanning-Tree Protocols (STP RSTP MSTP).pdf - Edukacja - Caveman85

Cisco AVVID Network Infrastructure:

Implementing 802.1w and 802.1s in

Campus Networks

Implementation Guide

April, 2003

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Cisco AVVID Network Infrastructure: Implementing 802.1w and 802.1s in Campus Networks

CONTENTS

About this Guide vii

Intended Audience vii

Document Organization

vii

Document Conventions

viii

Obtaining Documentation

viii

World Wide Web ix

Documentation CD-ROM

Ordering Documentation

Documentation Feedback

Obtaining Technical Assistance

Cisco.com x

Technical Assistance Center

Introduction 1-1

Hierarchical Campus Networks

CHAPTER 1

1-1

Data Centers 1-2

Wireless LANs 1-3

Spanning Tree Evolution

1-4

802.1D 1-4

Cisco 802.1D Enhancements 1-5

Rapid and Multiple Spanning Tree

1-5

Understanding Rapid Spanning-Tree Protocol (802.1w)

CHAPTER 2

2-1

New Port States and Port Roles

2-2

Port States

2-2

Port Roles

2-2

New BPDU Format

2-5

New BPDU Handling 2-6

Faster Aging of Information 2-6

Accepting Inferior BPDUs 2-6

Rapid Transition to Forwarding State

2-7

Edge Ports

2-7

Link Type

2-7

Convergence in 802.1D

2-7

Cisco AVVID Network Infrastructure: Implementing 802.1w and 802.1s in Campus Networks

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Contents

Convergence in RSTP 2-9

Proposal/Agreement Handshake Sequence

2-10

New Topology Change Mechanisms

2-12

Topology Change Detection 2-13

Topology Change Propagation 2-13

Compatibility with 802.1D

2-14

Understanding Multiple Spanning-Tree Protocol (802.1s)

CHAPTER 3

3-1

Comparing MSTP with Other STPs

3-1

Per-VLAN Spanning Tree+ 3-2

Rapid Per-VLAN Spanning Tree+

3-2

Standard 802.1q 3-2

Multiple Spanning Tree

3-3

MST Regions 3-4

MSTP Configuration and MST Region

3-5

Region Boundary

3-5

MST Instances

3-6

MSTIs

3-6

IST 3-7

MST Hop Count 3-8

Interaction Between the MST Region and the Outside World

3-9

Recommended Configuration 3-10

Alternate Configuration (Not Recommended)

3-11

Invalid Configuration 3-12

Common Misconfigurations 3-13

IST Instance is Active on All Ports, Whether Trunk or Access 3-13

Two VLANs Mapped to the Same Instance Will Block the Same Ports

3-14

Deploying RSTP and MSTP

CHAPTER 4

4-1

Data Center Topology 4-1

RSTP Active Topology 4-2

RSTP Convergence Example

4-2

RSTP Link Failure Recovery

4-5

Configuring Rapid-PVST+

4-7

Configuring MSTP 4-9

MST Region 4-9

MAC Address Reduction 4-10

Configuring MSTP at the Distribution Level

4-11

Cisco AVVID Network Infrastructure: Implementing 802.1w and 802.1s in Campus Networks

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Contents

Configuring MSTP at the Access Layer

4-13

Interaction Between STPs 4-15

Rapid-PVST+ Interacting with PVST+

4-15

Rapid-PVST+ Interacting with MSTP

4-16

MSTP Interaction (General) 4-16

IST Interacting with STP 4-16

IST Interacting with PVST+ 4-17

IST Interacting with 802.1q CST

4-19

RSTP in a Stack

4-20

Link Type 4-21

Migration Strategy 4-22

Spanning Tree Logical Ports 4-23

Spanning Tree Extensions 4-23

Spanning-Tree PortFast, BPDU Guard, and BPDU Filtering

4-23

Spanning-Tree Loop Guard

4-26

Cisco AVVID Network Infrastructure: Implementing 802.1w and 802.1s in Campus Networks

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CISCO - Spanning-Tree Protocols (STP RSTP MSTP).pdf

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