Users Guide

• 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.
• 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 configure 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.
Configuring Interfaces for Layer 2 Mode
All interfaces on all switches that participate in spanning tree must be in Layer 2 mode and enabled.
Figure 123. Example of Configuring Interfaces for Layer 2 Mode
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Spanning Tree Protocol (STP)