(Revised 2010-9-27) Page 155 of 159
Example 5 – Basic understanding of Overlapping VLANs
Receiving
Port #
Tagged VID
in packet
Destination
Address
Transmitting
Port #s
Notes
TX1
Untagged
MAC on port TX2,
VID=4
TX2
Unicast Traffic
TX1
Untagged
MAC on port TX3
TX2
Floods VLAN 4
TX1
VID 4
MAC on port TX2,
VID=4
TX2
Strips VID off packet
TX1
VID 4
Unknown MAC
TX2
Strips VID off packet & Floods VLAN 4
TX2
Untagged
MAC on port TX1,
VID=2
TX1
Unicast Traffic
TX2
Untagged
MAC on port TX5,
VID=2
TX5
Unicast Traffic
TX2
VID 2 or 3
MAC on port TX5,
VID=2 and 3
TX5
Strips VID off packet (or floods if MAC
is unknown for VID)
TX2
Untagged
Unknown MAC
TX1, TX3-TX8
Floods VLAN 2
TX3
Untagged
MAC on port TX1,
VID=3
TX2, TX4-TX8
Floods VLAN 3
TX3
Untagged
MAC on port TX2,
VID=3
TX2
Unicast Traffic
TX3
Untagged
MAC on port TX5,
VID=3
TX5
Unicast Traffic
TX3
VID 2 or 3
MAC on port TX2,
VID=2 and 3
TX2
Strips VID off packet (or floods if MAC
is unknown for VID)