Spanning Tree
STP Flavors
Cisco Sx350, SG350X, SG350XG, Sx550X & SG550XG Series Managed Switches, Firmware Release 2.2.5.x
This section describes the Spanning Tree Protocol (STP) (IEEE802.1D and IEEE802.1Q) and
covers the following topics:
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STP Flavors
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STP Status and Global Settings
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STP Interface Settings
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RSTP Interface Settings
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Multiple Spanning Tree Overview
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MSTP Properties
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VLANs to a MSTP Instance
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MSTP Instance Settings
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MSTP Interface Settings
STP 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 stop transferring user
data. After the topology changes so that the data transfer is made possible, the links are
automatically re-activated.
Loops occur when alternate paths exist between hosts. Loops can cause switches to relay the
same packets indefinitely, resulting packets not arriving at their destination, Broadcast/
Multicast storms and reduced network efficiency.
STP provides a tree topology for any arrangement of switches and interconnecting links, by
creating a unique path between end stations on a network, and thereby eliminating loops.
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