3Com S7902E, Configuration Manual

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To change the link type of a port from trunk to hybrid or vice versa, you must set the link type to
access first.
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Before assigning a hybrid port to a VLAN, create the VLAN first.
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After configuring the default VLAN for a hybrid port, you must use the port hybrid vlan command
to configure the hybrid port to allow packets from the default VLAN to pass through, so that the
egress port can forward packets from the default VLAN.
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After you configure a command on a Layer 2 aggregate interface, the system starts applying the
configuration to the aggregate interface and its aggregation member ports. If the system fails to do
that on the aggregate interface, it stops applying the configuration to the aggregation member ports.
If it fails to do that on an aggregation member port, it simply skips the port and moves to the next
port.
MAC-Based VLAN Configuration
Introduction to MAC-Based VLAN
MAC-based VLANs group VLAN members by MAC address. They only apply to untagged frames.
When receiving an untagged frame, the device looks up the list of MAC-to-VLAN mappings based on
the MAC address of the frame for a match. If a match is found, the system forwards the frame in the
corresponding VLAN. If no match is found, the system looks up other types of VLANs to make the
forwarding decision.
MAC-based VLANs are mostly used in conjunction with security technologies such as 802.1X to
provide secure, flexible network access for terminal devices.
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.