CCNP ENCOR Chapter 2: Spanning Tree Protocol (STP) Summary

Chapter 2: Spanning Tree
Instructor Materials



CCNP Enterprise: Core Networking

,Chapter 2 Content

This chapter covers the following content:


• Spanning Tree Protocol Fundamentals - This section provides an overview of
how switches become aware of other switches and prevent forwarding loops.
• Rapid Spanning Tree Protocol - This section examines the improvements
made to STP for faster convergence.




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,Spanning Tree Protocol
Fundamentals
• Spanning Tree Protocol (STP) enables switches to become aware of other switches
through the advertisement and receipt of bridge protocol data units (BPDUs).
• STP operates by selecting a master switch and running a tree-based algorithm to
identify which redundant ports should not forward traffic.




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, Spanning Tree Protocol Fundamentals
Spanning Tree Versions
STP has multiple iterations:
• 802.1D, which is the original specification
• Per-VLAN Spanning Tree (PVST)
• Per-VLAN Spanning Tree Plus (PVST+)
• 802.1W Rapid Spanning Tree Protocol (RSTP)
• 802.1S Multiple Spanning Tree Protocol (MST)

Note: Catalyst switches now operate in PVST+, RSTP, and MST modes.
All three of these modes are backward compatible with 802.1D.




© 2016 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4