Filter
Top Products
VLAN Switch Operation
802.1Q VLAN User’s Guide 2-3
2.3.3 Customizing the VLAN Forwarding List
Each port on a VLAN aware switch has a VLAN forwarding list that
contains, as a minimum, the PVID of the VLAN configured. Additionally,
the Port VLAN Forwarding List of each port can be configured to allow
any number of VLANs to be added to its list. In the case of GMRP
(dynamic VLANs), the list can have VLANs added and deleted by the
switch as directed by the protocol.
2.4 VLAN SWITCH OPERATION
IEEE 802.1Q VLAN switches act on the classification of frames into
VLANs. Sometimes, VLAN classification is based on tags in the headers
of data frames. These VLAN tags are added to data frames by the switch
as the frames are transmitted out certain ports, and are later used to make
forwarding decisions by the switch and other VLAN aware switches. In
the absence of a VLAN tag header, the classification of a frame into a
particular VLAN depends upon the configuration of the switch port that
received the frame.
The operation of an 802.1Q VLAN switch is best understood from a point
of view of the switch itself. To illustrate this concept, the examples that
follow view the switch operations from
inside
the switch.