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Cisco Small Business 300 Series Managed Switch Administration Guide 127
Configuring the Spanning Tree Protocol
The Spanning Tree Protocol (STP) (IEEE802.1D and IEEE802.1Q) is enabled by
default, set to RSTP (Rapid Spanning Tree Protocol) mode, and protects a Layer 2
Broadcast domain from broadcast storms by selectively setting links to standby
mode to prevent loops. In standby mode, these links temporarily do not transfer
user data. They are automatically re-activated when the topology changes to
make it desirable to transfer user data.
This chapter contains the following topics:
•STP Flavors
• Configuring STP Status and Global Settings
• Defining Spanning Tree Interface Settings
• Configuring Rapid Spanning Tree Settings
• Multiple Spanning Tree
• Defining MSTP Properties
• Mapping VLANs to a MST Instance
• Defining MST Instance Settings
• Defining MSTP Interface Settings
STP Flavors
Loops occur when alternate routes exist between hosts. Loops in an extended
network can cause Layer 2 switches to forward traffic indefinitely, resulting in
increased traffic and reduced network efficiency.
STP provides a tree topology for any arrangement of Layer 2 switches and
interconnecting links, creating a unique path between end stations on a network,
eliminating loops.