1. www.ciscopress.com Copyright 2003 CCNA 3 Chapter 8 Spanning Tree Protocol By Your Name

2. www.ciscopress.com Copyright 2003 Objectives Redundant topologies Spanning Tree Protocol

3. www.ciscopress.com Copyright 2003 Redundancy Redundant networking topologies are designed to ensure that networks continue to function in the presence of single points of failure.

4. www.ciscopress.com Copyright 2003 Redundant Topologies A goal of redundant topologies is to eliminate network outages caused by a single point of failure. All networks need redundancy for enhanced reliability.

5. www.ciscopress.com Copyright 2003 Redundant Switched Topologies

6. www.ciscopress.com Copyright 2003 Broadcast Storms

7. www.ciscopress.com Copyright 2003 Multiple Frames Transmission

8. www.ciscopress.com Copyright 2003 MAC Database Instability In a redundant switched network, it is possible for switches to learn the wrong information. A switch can learn that a MAC address is on a port when it is not.

9. www.ciscopress.com Copyright 2003 Spanning Tree Protocol

10. www.ciscopress.com Copyright 2003 Bridging Loops for Redundancy

11. www.ciscopress.com Copyright 2003 Spanning Tree

12. www.ciscopress.com Copyright 2003 Spanning-Tree Costs

13. www.ciscopress.com Copyright 2003 Spanning-Tree Operation One root bridge per network. One root port per nonroot bridge. One designated port per segment. Nondesignated ports are unused.

14. www.ciscopress.com Copyright 2003 Selecting the Root Bridge Bridge protocol data unit (BPDU)

15. www.ciscopress.com Copyright 2003 Spanning-Tree Port States

16. www.ciscopress.com Copyright 2003 Spanning-Tree Recalculation A switched internetwork has converged when all the switch and bridge ports are in either the forwarding or blocked state.

17. www.ciscopress.com Copyright 2003 Rapid Spanning Tree Protocol Clarification of port states and roles Definition of a set of link types that can go to forwarding state rapidly Allowing switches, in a converged network, to generate their own BPDUs rather than relaying root bridge BPDUs The Rapid Spanning Tree Protocol, IEEE 802.1w, will eventually replace the Spanning Tree Protocol, IEEE 802.1D.