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| Chapter 49 IEEE 802.1Q Tagged VLAN Commands |
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= The VLAN ID [1 – 4094]. | ||
= | A name to identify the SVLAN entry. | |
= | This is the Switch port list. | |
•Enter fixed to register the
•Enter normal to confirm registration of the
•Enter forbidden to block a
•Enter no fixed or no forbidden to change
•Enter untagged to send outgoing frames without a tag.
•Enter no untagged to tag outgoing frames.
49.3.4.1Modify a Static VLAN Table Example
The following example configures ports 1 to 5 as fixed and untagged ports in VLAN 2000.
sysname (config)# vlan 2000 sysname
49.3.4.2 Forwarding Process Example
49.3.4.2.1Tagged Frames
1First the Switch checks the VLAN ID (VID) of tagged frames or assigns temporary VIDs to untagged frames.
2The Switch then checks the VID in a frame’s tag against the SVLAN table.
3The 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).
4Then 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.
49.3.4.2.2Untagged Frames
1An untagged frame comes in from the LAN.
2The Switch checks the PVID table and assigns a temporary VID of 1.
3The 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.
4If 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.
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