Chapter 56 IEEE 802.1Q Tagged VLAN and Isolation Commands
IES-1248-51V User’s Guide
413
56.3.4.1 Modify a Static VLAN Table Example
The following is an example of how to modify a static VLAN table.
56.3.4.2 Forwarding Process Example
Tagged Frames
1 First the IES-1248-51V checks the VLAN ID (VID) of tagged frames or assigns
temporary VIDs to untagged frames (see Section 56.3.2 on page 412).
2 The IES-1248-51V checks the frame’s source MAC address against the MAC filter.
3 The IES-1248-51V then checks the VID in a frame’s tag against the SVLAN table.
4 The IES-1248-51V notes what the SVLAN table says (that is, the SVLAN tells the
IES-1248-51V whether or not to forward a frame and if the forwarded frames
should have a tag).
5 Frames might be dropped if they are sent to a CPE (customer premises
equipment) xDSL device that does not accept tagged frames.
Untagged Frames
1 An untagged frame comes in from the LAN.
2 The IES-1248-51V checks the frame’s source MAC address against the MAC filter.
3 The IES-1248-51V checks the PVID table and assigns a VID and IEEE 802.1Q
priority.
4 The IES-1248-51V ignores the port from which the frame came, because the IES-
1248-51V does not send a frame to the port from which it came. The IES-1248-
51V also does not forward frames to “forbidden” ports.
5 If after looking at the SVLAN, the IES-1248-51V does not have any ports to which
it will send the frame, it drops the frame.
ras> switch vlan set 2000 1:FU
ras> switch vlan set 2001 2:FU
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