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3.3.5 VLAN Group Table Configuration
The switch provides a table of eight VLAN groups to support up to eight VLANs at the same time.
Each VLAN group is associated to one unique VLAN. The table is referred for VLAN classification.
A VLAN group contains the following configuration settings:
VID
: 12-bit VLAN Identifier index to the VLAN to which the group is associated
Member Ports
: the admitted egress ports for packets belonging to this VLAN
Source Port Check
: the ingress port of the packet must also be the member port of this VLAN.
Otherwise, the packet is discarded.
3.3.6 VLAN Classification
VLAN classification is a process to classify a VLAN group to which a received packet belongs. The
VID of the generated Packet Tag information associated to the received packet is used as an index for
VLAN group table lookup. The VID matched VLAN group will be used for packet forwarding. If no
matched VLAN group is found in table lookup, the packet is dropped.
Refer to section 3.2.4 for details about how the Packet Tag information is generated.
The member ports specified in the matched VLAN group are the admitted egress port range for the
packet. The packet will never be forwarded to other ports which are not in the member ports.
The Source Port Check setting of the matched VLAN group is also referred. If it is enabled, the
ingress port will be checked whether it is a member port of this group.
3.3.7 Packet Forwarding
The forwarding is a process to forward the received packet to one or more egress ports. The process
uses the following information as forwarding decision:
•
Member ports of the matched VLAN group : the egress port range for forwarding
•
Source Port Check setting of the matched VLAN group : check ingress port membership
•
The packet destination MAC address : for MAC address table loop up
•
The switch MAC address table : to find the associated port where a MAC address is learned
If the MAC address table lookup is matched and the learned port is the VLAN member port, the
packet is forwarded to the port (egress port). If the lookup failed, the switch will broadcast the packet
to all member ports.
