338 | Multiple Spanning Tree Protocol (MSTP)
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The Dell Force10 operating software (FTOS) supports three other variations of Spanning Tree 
(Table 19-1).
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 MXL Switch, 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. 
2. Place the interfaces in VLANs.
3. Enable MSTP 
4. Create MSTP instances and map VLANs to them. 
Related Configuration Tasks
• Create Multiple Spanning Tree Instances
• Create Multiple Spanning Tree Instances
• Influence MSTP Root Selection
• Interoperate with Non-FTOS Bridges
• Modify Global Parameters
• Enable BPDU Filtering globally
• Enable BPDU Filtering globally
• Configure an EdgePort
• Flush MAC Addresses after a Topology Change
• Debugging and Verifying an MSTP Configuration
Table 19-1.  FTOS Supported Spanning Tree Protocols
Dell Force10 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