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MAC-Based VLAN Configuration
Introduction to MAC-Based VLAN
MAC-based VLANs group VLAN members by MAC address. They are mostly used in conjunction with
security technologies such as 802.1X to provide secure, flexible network access for terminal devices.
MAC-based VLAN implementation
With MAC-based VLAN configured, the device processes received packets as follows:
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When receiving an untagged frame, the device looks up the list of MAC-to-VLAN mappings based
on the source MAC address of the frame for a match. Two matching modes are available: exact
matching and fuzzy matching. In exact matching mode, the device searches the MAC-to-VLAN
mappings whose masks are all-Fs. If the MAC address in a MAC-to-VLAN mapping matches the
source MAC address of the untagged frame exactly, the device ends the search and adds a VLAN
tag containing the corresponding VLAN ID to the packet. In fuzzy matching mode, the device
searches the MAC-to-VLAN mappings whose masks are not all-Fs and performs a logical AND
operation on the keyword and each mask. If the result of an AND operation matches the
corresponding MAC address exactly, the device ends the search the adds a VLAN tag containing
the corresponding VLAN ID to the packet. If no match is found, the system looks up other types of
VLANs to make the forwarding decision.
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When receiving a tagged frame, the receiving port forwards the frame if it is assigned to the
corresponding VLAN or drops the frame if it is not. In this case, port-based VLAN applied.
Approaches to Creating MAC Address-to-VLAN Mappings
In addition to creating MAC address-to-VLAN mappings at the CLI, you can use an authentication
server to automatically issue MAC address-to-VLAN mappings.
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Manually Static configuration (through CLI)
You can associate MAC addresses with VLANs by using corresponding commands.
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Automatic configuration through the authentication server (that is, VLAN issuing)
The device associates MAC addresses with VLANs dynamically based on the information provided by
the authentication server. If a user goes offline, the corresponding MAC address-to-VLAN association is
removed automatically. Automatic configuration requires MAC address-to–VLAN mapping be
configured on the authentication server. For detailed information, refer to
802.1X Configuration
in the
Security Volume
.
The two configuration approaches can be used at the same time, that is, you can configure a MAC
address-to-VLAN entry on both the local device and the authentication server at the same time. Note
that the MAC address-to-VLAN entry configuration takes effect only when the configuration on the local
device is consistent with that on the authentication server. Otherwise, the previous configuration takes
effect.
Configuring a MAC Address-Based VLAN
