Reference Guide

Spanning Tree Protocol (STP) | 873
45
Spanning Tree Protocol (STP)
Spanning Tree Protocol (STP) is supported on platforms: e c s z
Protocol Overview
Spanning Tree Protocol (STP) is a Layer 2 protocol—specified by IEEE 802.1d—that eliminates loops in a
bridged topology by enabling only 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. Layer 2 loops, which can occur in a network due to poor network
design and without enabling protocols like xSTP, can cause unnecessarily high switch CPU utilization and
memory consumption.
FTOS supports three other variations of Spanning Tree, as shown here:
Configuring Spanning Tree
Configuring Spanning Tree is a two-step process:
1. Configure interfaces for Layer 2. See page 49.
2. Enable Spanning Tree Protocol. See page 876.
Table 45-1. FTOS Supported Spanning Tree Protocols
Dell Force10Term IEEE Specification
Spanning Tree Protocol (STP) 802.1d
Rapid Spanning Tree Protocol
(RSTP)
802.1w
Multiple Spanning Tree Protocol
(MSTP)
802.1s
Per-VLAN Spanning Tree Plus
(PVST+)
Third Party