Configuring Spanning Tree Protocol; Understanding Spanning Tree Protocol (Stp) - Allen-Bradley Stratix 5100 User Manual

Understanding Spanning
Tree Protocol (STP)

Configuring Spanning Tree Protocol

This chapter describes how to configure Spanning Tree Protocol (STP) on your
access point.
Topic

Understanding Spanning Tree Protocol (STP)

Understanding Spanning Tree Protocol (STP)
Access Point/Bridge Protocol Data Units
Access Point/Bridge Protocol Data Units
Election of the Spanning-tree Root
Spanning-tree Timers
Creating the Spanning-tree Topology
Configuring STP Features
STP Configuration Examples
Root Bridge with VLANs
Displaying Spanning-tree Status
IMPORTANT STP is available only when the access point is in bridge mode.
STP is a Layer 2 link management protocol that provides path redundancy while
preventing loops in the network. For a Layer 2 Ethernet network to function
properly, one active path can only exist between any two stations. Spanning-tree
operation is transparent to end stations, that cannot detect whether they are
connected to a single LAN segment or to a LAN of multiple segments.
When you create fault-tolerant internet-works, you must have a loop-free path
between all nodes in a network. The spanning-tree algorithm calculates the best
loop-free path throughout a Layer 2 network. Infrastructure devices such as
wireless access points and switches send and receive spanning-tree frames, called
bridge protocol data units (BPDUs), at regular intervals. The devices don't
forward these frames but use them to construct a loop-free path.
Multiple active paths among end stations cause loops in the network. If a loop
exists in the network, end stations can receive duplicate messages. Infrastructure
devices can also learn end-station MAC addresses on multiple Layer 2 interfaces.
These conditions result in an unstable network.
Rockwell Automation Publication 1783-UM006A-EN-P - May 2014
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