Administrator Guide

Congure Spanning Tree
Conguring spanning tree is a two-step process.
• Conguring Interfaces for Layer 2 Mode
• Enabling Spanning Tree Protocol Globally
Related Conguration 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
• Conguring 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 avor of spanning tree at any one time.
• All ports in virtual local area networks (VLANs) and all enabled interfaces in Layer 2 mode are automatically added to the spanning tree
topology at the time you enable the protocol.
• To add interfaces to the spanning tree topology after you enable STP, enable the port and congure it for Layer 2 using the
switchport command.
• The IEEE Standard 802.1D allows 8 bits for port ID and 8 bits for priority. The 8 bits for port ID provide port IDs for 256 ports.
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Spanning Tree Protocol (STP)