Administrator Guide

Spanning Tree Protocol (STP)
Dell Networking OS supports spanning tree protocol (STP).
Topics:
• Protocol Overview
• Congure Spanning Tree
• Conguring Interfaces for Layer 2 Mode
• Enabling Spanning Tree Protocol Globally
• Adding an Interface to the Spanning Tree Group
• Removing an Interface from the Spanning Tree Group
• Modifying Global Parameters
• Modifying Interface STP Parameters
• Enabling Port Fast
• Global BPDU Filtering
• Selecting STP Root
• STP Root Guard
• SNMP Traps for Root Elections and Topology Changes
• Displaying STP Guard Conguration
Protocol Overview
STP is a Layer 2 protocol — specied 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.
The Dell Networking OS supports three other variations of spanning tree, as shown in the following table.
Table 77. Dell Networking OS Supported Spanning Tree Protocols
Dell Networking Term IEEE Specication
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
Congure Spanning Tree
Conguring spanning tree is a two-step process.
• Conguring Interfaces for Layer 2 Mode
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780 Spanning Tree Protocol (STP)