The main function
of the Spanning Tree Protocol (STP) is to allow redundant
switched/bridged paths without suffering the effects of loops in the
network. Spanning Tree allows for multiple links between
switches, but only one link is active (Forwarding mode), while all
other redundant links are in standby (Blocking mode) in case the
primary link fails.
Question:
What would happen without Spanning Tree, and if there were multiple
links between two switches?
Answer:
This could cause frames to be forwarded out the wrong switch ports, or
even worse, cause layer 2 broadcast storms. Remember that a broadcast
storm is when frames keep getting duplicated on a switched network,
until it finally overwhelms the network, and bringing the network
down.
Spanning Tree is important even in
networks where there are no redundant links between switches. It is
not uncommon for someone to accidentally connect a link between two
switches when a connection already exists. Spanning Tree is an
excellent safeguard from keeping a mistake like this from bringing
down a network.
For more information on Spanning Tree
Protocol and how it works, review the Power Point presentation on
Spanning Tree in Semester 3.
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