ZyXEL Communications IES-2000, User Manual

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IES-2000/3000 User’s Guide
IEEE 802.1Q Tagged VLAN Commands 11-9
Figure 11-4 SVLAN Example
An untagged frame comes in from the LAN.
Step 1.
An untagged frame comes in from the LAN.
Step 2.
The switch checks the PVID table and assigns a temporary VID of 1.
Step 3.
The switch ignores port# 1 (the LAN port where the frame came in), because the switch does not send a
frame to the port that it came in through.
Step 4.
The switch sees that port # 2, 3, 4, 6, 8 and 9 through 25 (DSL ports 1, 2, 3, 5, 7, 8 and 9 through 24)
are all set to “fixed” and “untag” which means the SVLAN allows the frame to be sent to those ports
without a tag.
Step 5.
Port # 5 is “forbidden” so the frame is not forwarded to DSL port # 4.
Step 6.
Port # 7 (DSL port 6) is “normal” which means that it was entered dynamically, so the SVLAN permits
the frame to be forwarded to port # 7 if port # 7 is registered in the DVLAN table.
Step 7.
After looking at the SVLAN, the switch sees that the port filter is set for port 1 (the LAN port) to
forward frames to all of the ADSL ports, so the switch forwards everything that the SVLAN permits.