LAN9118MT Standard Microsystems (SMSC), LAN9118MT Datasheet - Page 29

• Manufacturer Part Number: LAN9118MT
• Manufacturer: Standard Microsystems (SMSC)

High-Performance Single-Chip 10/100 Non-PCI Ethernet Controller
Datasheet
SMSC LAN9118
LAN Switch #2
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Network efficiency: Allows shielding one system resource from traffic not meant for that resource. A
workstation in one VLAN is shielded from traffic on another VLAN, increasing that workstation’s
efficiency.
Broadcast containment: Leakage of broadcast frames from one VLAN to another is prevented.
When the members of a VLAN are not located on the same physical medium, the VLAN uses a tag
to help it determine how to forward the frame from one member to another. The tag structure was
proprietary until the IEEE released a supplement to 802.3 defining the VLAN frame structure, including
the tag. This new frame structure for VLAN is depicted in Figure 4.2, "VLAN Frame".
VLAN 3
BBB
Address
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CCC
DDD
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AAA
BBB
EEE
FFF
CCC
VLAN Config Data
Figure 4.1 VLAN Topology
LAN Switch #1
VLAN #
VLAN 3
VLAN 3
VLAN 3
VLAN 2
VLAN 2
VLAN 2
VLAN 1
VLAN 1
DATASHEET
DDD
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VLAN 2
EEE
FFF
LAN Switch #3
GGG
VLAN 1
Revision 1.0 (03-17-05)
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