Matakuliah
Tahun
Versi
: T0374/Applied Networking 1
: 2008
: <<versi/revisi>>
Pertemuan 17
Ethernet Switching
1
Discussion Topics
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•
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Layer 2 bridging
Layer 2 switching
Switch operation
Latency
Switch modes
Spanning-Tree Protocol
2
Layer 2 Bridging
Bridges
Switch Operation
Full Duplex
Network Latency
Switch Modes
• Store and Forward - A switch receives the
entire frame before sending it out the
destination port.
• Cut-Through - A switch starts to transfer
the frame as soon as the destination MAC
address is received.
Spanning-Tree Operation
STP States
Spanning Tree Protocol (STP)
• STP is a loop-prevention
protocol
• Uses the Spanning Tree
Alogithm
• STP allows L2 devices to
communicate with each other
to discover physical loops in
the network.
• STP specifies an algorithm
that L2 devices can use to
create a loop-free logical
topology.
• STP creates a tree structure
of loop-free leaves and
branches that spans the entire
Layer 2 network.
Rick Graziani
graziani@cabrillo.edu
11
Redundancy Creates Loops
Rick Graziani
graziani@cabrillo.edu
12
Spanning Tree – Only for
Loops
• Loops may occur in
your network as
Two users interconnecting the
part of a a design
switches in their cubicles.
strategy for
redundancy.
• STP is not needed
if there are no loops
in your network.
• However, DO NOT
disable STP!
Rick Graziani
13
• Loops can occurgraziani@cabrillo.edu