B&B Electronics 708TX - Manual - Manual (Page 150)

(Revised 2010-7-30) Page 150 of 154
Example 6 – Basic understanding of VLANs with Multicast Filtering
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Receiving
Port # Tagged VID
in packet Destination
Address Transmitting
Port #s Notes
TX1 Untagged 01:00:00:00:00:01 TX2
Goes to ports TX1-TX8, but TX1 can only
send to TX2 (VLAN 4)
TX3 Untagged 01:00:00:00:00:02 TX6, TX8
Goes to ports TX2, TX6-TX8 (VLAN 3) but
filter keeps it on ports TX6 and TX8 only
TX2 Untagged 01:00:00:00:00:01 TX1,TX3-TX8
Goes to ports TX1-TX8, but won‘t go back
out the port it came in on
TX2 Untagged 01:00:00:00:00:02 TX1,TX3-TX8 Goes to ports TX1,TX3-TX8
TX3 Untagged 01:00:00:00:00:01 TX2, TX4-TX8 Goes to ports TX2, TX4-TX8
TX6 Untagged 01:00:00:00:00:02 TX8 Goes to port TX8
TX3 Untagged 01:00:00:00:00:02 TX6, TX8 Goes to ports TX6 and TX8
Note: If there are multiple ports on different VLANs, the 708 will apply the static multicast address to the
lowest VLAN-ID that is associated with one of the ports assigned to the static multicast address. If the
lowest VLAN-ID contains all the ports assigned to the static multicast address (an umbrella VLAN), it will
function for all those ports with no problems. This can be achieved with overlapping VLANs.
For further information and examples on overlapping vlans, see:
http://www.n-tron.com/pdf/OverlappingPortVLAN.pdf