7.6.1.0 - Force10 Networks

Chapter 16 Spanning Tree Protocol
Protocol Overview
Spanning Tree Protocol (STP) is a Layer 2 protocol—described by IEEE 802.1d—that eliminates loops in
a bridged topology by enabling a single path through the network. By eliminating loops, the protocol
improves scalability in a large network and enables you to implement redundant paths, which can be
activated upon the failure of active paths.
Configuring Spanning Tree
Implementing Spanning Tree is a two-step process:
1. Configure interfaces for Layer 2. See page 334.
2. Enable Spanning Tree Protocol. See page 335.
Related Configuration Tasks
• Adding an Interface to the STG on page 338
• Removing an Interface from the STG on page 338
• Modifying Global Parameters on page 338
• Modifying Interface Parameters on page 339
• Enabling PortFast on page 340
• Preventing Network Disruptions with BPDU Guard on page 341
• Influencing STP Root Selection on page 342
• Conserving Processing Resources with BPDU Filtering on page 342
• SNMP Traps for Root Elections and Topolgy Changes on page 343
Important Points to Remember
• Spanning Tree Protocol is disabled by default.
• FTOS supports only one Spanning Tree instance (0).
• All ports in VLANs and all enabled interfaces in Layer 2 mode are automatically added to the
Spanning Tree topology.
FTOS Configuration Guide, version 7.6.1.0 333