GS-4012F/4024 User’s Guide
Chapter 42 IEEE 802.1Q Tagged VLAN Commands 294
•Enter forbidden to block a <port-list> from joining the static VLAN table with
<vlan-id>.
•Enter
no fixed
or no forbidden
to change <port-list>
to normal status.•Enter
untagged to send outgoing frames without a tag.
•Enter
no untagged to tag outgoing frames.
42.5.4.1 Modify a Static VLAN Table Example
The following example configures ports 1 to 5 as fixed and untagged ports in VLAN 2000.
Figure 201 Modifying Static VLAN Example
42.5.4.2 Forwarding Process Example
Tagged Frames
1 First the switch checks the VLAN ID (VID) of tagged frames or assigns temporary VIDs
to untagged frames.
2 The switch then checks the VID in a frame’s tag against the SVLAN table.
3 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).
4 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.
Untagged Frames
1 An untagged frame comes in from the LAN.
2 The switch checks the PVID table and assigns a temporary VID of 1.
3 The switch ignores the port from which the frame came, because the switch does not send
a frame to the port from which it came. The switch also does not forward frames to
“forbidden” ports.
4 If after looking at the SVLAN, the switch does not have any ports to which it will send
the frame, it won’t check the port filter.
42.5.5 Delete VLAN ID
Syntax:
no vlan <vlan-id>
ras (config)# vlan 2000
ras (config-vlan)# fixed 1-5
ras (config-vlan)# untagged 1-5
