Reference Guide
644 | Multiple Spanning Tree Protocol
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FTOS supports three other variations of Spanning Tree, as shown in Table 44.
Implementation Information
• The FTOS MSTP implementation is based on IEEE 802.1Q-2003, and interoperates only with bridges
that also use this standard implementation.
• MSTP is compatible with STP and RSTP.
• FTOS supports only one MSTP region.
• When you enable MSTP, all ports in Layer 2 mode participate in MSTP.
• On the C-Series and S-Series, you can configure 64 MSTIs including the default instance 0 (CIST).
Configure Multiple Spanning Tree Protocol
Configuring Multiple Spanning Tree is a four-step process:
1. Configure interfaces for Layer 2. See Configuring Interfaces for Layer 2 Mode.
2. Place the interfaces in VLANs.
3. Enable Multiple Spanning Tree Protocol. See Enable Multiple Spanning Tree Globally.
4. Create Multiple Spanning Tree Instances, and map VLANs to them. See page 645.
Related Configuration Tasks
• Create Multiple Spanning Tree Instances
• Add and Remove Interfaces
• Influence MSTP Root Selection
• Interoperate with Non-FTOS Bridges
• Modify Global Parameters
• Modify Interface Parameters
• Configure an EdgePort
• Flush MAC Addresses after a Topology Change
• Debugging and Verifying MSTP Configuration
• Preventing Network Disruptions with BPDU Guard
• SNMP Traps for Root Elections and Topology Changes
• Configuring Spanning Trees as Hitless
Table 29-1. FTOS Supported Spanning Tree Protocols
Dell Networking Term IEEE Specification
Spanning Tree Protocol 802.1d
Rapid Spanning Tree Protocol 802.1w
Multiple Spanning Tree Protocol 802.1s
Per-VLAN Spanning Tree Plus Third Party










