ZyXEL Communications ZyXEL DMA 1000 - Manual (Page 83)

IES-1000 User’s Guide
IEEE 802.1Q Tagged VLAN Commands 10-7
1. 192.168.1.1 vlan1q> svlan setentry 3 3 fixed untag
2. 192.168.1.1 vlan1q> svlan setentry 2 2 fixed untag
3. 192.168.1.1 vlan1q> svlan setentry 1 1 fixed tag
4. 192.168.1.1 vlan1q> svlan list
The arrows in the figure shown next point to the lines that have been modified in this table as a result of the
previous commands.
Figure 10-3 Example: SVLAN List Command Display
Forwarding Process Example
The switch uses the SVLAN in making frame-forwarding decisions.
First the switch checks the MAC address in a frames header against the MAC filtering database.
Next the switch checks the VLAN ID (VID) of tagged frames or assigns temporary VIDs to untagged frames (see
the PVID Command).
The switch then checks the VID in a frame’s tag against the SVLAN table.
The switch notes what the SVLAN table says (that is, the SVLAN tells the switch whether or not to forward a
frame and if the forwarded frames should have tags).
Then the switch applies the port filter to finish the forwarding decision. This means that frames may be dropped
even if the SVLAN says to forward them. Frames might also be dropped if they are sent to a CPE (customer
premises equipment) DSL device that does not accept tagged frames.
The following figure shows the flow of the decision process used with a broadcast frame (one that is meant to go
to all of the ports).
vid port# ad_control tag_control
-------- ------- ------------ ------------
1
1 fixed tag
2 normal untag
3 normal untag
2 1 normal untag
2 fixed untag
3 normal untag
3 1 normal untag
2 normal untag
3 fixed untag
3.
2.
1.