Dell S4048-ON, Configuration Manual

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Spanning Tree Protocol (STP)
The spanning tree protocol (STP) is supported on Dell Networking OS.
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 Networking OS supports three other variations of spanning tree, as shown in the following table.
Table 93. Dell Networking OS Supported Spanning Tree Protocols
Dell 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
• Modifying Global Parameters
• Modifying Interface STP Parameters
• Enabling PortFast
• Prevent Network Disruptions with BPDU Guard
• STP Root Guard
• Enabling SNMP Traps for Root Elections and Topology Changes
• Configuring Spanning Trees as Hitless
Important Points to Remember
• STP is disabled by default.
• The Dell Networking OS supports only one spanning tree instance (0). For multiple instances, enable the multiple spanning tree
protocol (MSTP) or per-VLAN spanning tree plus (PVST+). You may only enable one flavor of spanning tree at any one time.
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Spanning Tree Protocol (STP)