Figure 11-3 Example: Svlan List Command Display; Forwarding Process Example - ZyXEL Communications IES-2000 User Manual

IES-2000/3000 User's Guide
1. 192.168.1.1 vlan1q> svlan setentry
2. 192.168.1.1 vlan1q> svlan setentry
3. 192.168.1.1 vlan1q> svlan setentry
4. 192.168.1.1 vlan1q> svlan list
The arrows, in the next figure, point to the lines in the static VLAN table that have been modified as a result of
the previous commands.
3.
2.
1.

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.
Step 1.
Next the switch checks the VLAN ID (VID) of tagged frames or assigns temporary VIDs to untagged
Step 2.
frames (see the PVID Command.
The switch then checks the VID in a frame's tag against the SVLAN table.
Step 3.
The switch notes what the SVLAN table says (that is, the SVLAN tells the switch whether or not to
Step 4.
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
Step 5.
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).
11-8
vid port#
-------- -------
1 1
2
3
2 1
2
3
3 1
2
3

Figure 11-3 Example: SVLAN List Command Display

3 3 fixed untag
2 2 fixed untag
1 1 fixed tag
ad_control tag_control
------------ ------------
fixed tag
normal untag
normal untag
normal untag
fixed untag
normal untag
normal untag
normal untag
fixed untag
IEEE 802.1QTagged VLAN Commands