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Vlan hierarchy – Allied Telesis AT-8100 Series User Manual

Page 990

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Chapter 64: MAC Address-based VLANs

990

VLAN Hierarchy

The switch employs a VLAN hierarchy when handling untagged packets
that arrive on a port that is an egress port of a MAC address-based VLAN
as well as an untagged port of a port-based VLAN. (A port can be a
member of both types of VLANs at the same time.) The rule is that a MAC
address-based VLAN takes precedence over that of a port-based VLAN.

When an untagged packet arrives on a port, the switch first compares the
source MAC address of the packet against the MAC addresses of all the
MAC address-based VLANs on the device. If there is a match, the switch
considers the packet as a member of the corresponding MAC address-
based VLAN and not the port-based VLAN, and forwards it out the egress
ports defined for the corresponding MAC address-based VLAN.

If there is no match, the switch considers the packet as a member of the
port-based VLAN and forwards the packet according to the PVID assigned
to the port. For an explanation of a PVID, refer to “Port-based VLAN
Overview” on page 904.

Table 104. Example of a MAC Address-based VLAN Spanning Switches

Switch A

Switch B

VLAN Name: Sales

VLAN Name: Sales

MAC Address

Egress Ports

MAC Address

Egress Ports

Address_1

1,3,4,5

Address_1

11,12,14,16

Address_2

1

Address_2

11

Address_3

1

Address_3

11

Address_4

1

Address_4

11

Address_5

1

Address_5

11

Address_6

1

Address_6

11