Administrator Guide

Spanning Tree Protocol (STP)
The spanning tree protocol (STP) is supported on Dell EMC Networking OS.
Topics:
• Protocol Overview
• Configure Spanning Tree
• Important Points to Remember
• Configuring Interfaces for Layer 2 Mode
• Enabling Spanning Tree Protocol Globally
• Adding an Interface to the Spanning Tree Group
• Modifying Global Parameters
• Modifying Interface STP Parameters
• Enabling PortFast
• Selecting STP Root
• STP Root Guard
• Enabling SNMP Traps for Root Elections and Topology Changes
• Configuring Spanning Trees as Hitless
• STP Loop Guard
• Displaying STP Guard Configuration
Protocol Overview
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 allows you to implement redundant paths, which
can be activated after 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.
Dell EMC Networking OS supports three other variations of spanning tree, as shown in the following table.
Table 117. Dell EMC Networking OS Supported Spanning Tree Protocols
Dell EMC Networking Term 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
Configure Spanning Tree
Configuring spanning tree is a two-step process.
● Configuring Interfaces for Layer 2 Mode
● Enabling Spanning Tree Protocol Globally
Related Configuration Tasks
● Adding an Interface to the Spanning Tree Group
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862 Spanning Tree Protocol (STP)