What is the Role of 802.1X in VLAN Assignment?
PowerConnect M6220, M6348, M8024, and M8024-k switches allow a port to
be placed into a particular VLAN based on the result of the authentication or
type of 802.1X authentication a client uses when it accesses the switch. The
authentication server can provide information to the switch about which
VLAN to assign the supplicant.
When a host connects to a switch that uses an authentication server to
authenticate, the host authentication can typically have one of three
The host is authenticated.
The host attempts to authenticate but fails because it lacks certain
The host is a guest and does not try to authenticate at all.
You can create three separate VLANs on the switch to handle a host
depending on whether the host authenticates, fails the authentication, or is a
guest. The RADIUS server informs the switch of the selected VLAN as part of
Authenticated and Unauthenticated VLANs
Hosts that authenticate normally use a VLAN that includes access to network
resources. Hosts that fail the authentication might be denied access to the
network or placed on a
Much of the configuration to assign hosts to a particular VLAN takes place on
the 802.1X authenticator (RADIUS server). If you use an external RADIUS
server to manage VLANs, you configure the server to use Tunnel attributes in
Access-Accept messages in order to inform the switch about the selected
VLAN. These attributes are defined in RFC 2868, and their use for dynamic
VLAN is specified in RFC 3580.
The VLAN attributes defined in RFC3580 are as follows:
VLANID is 12-bits and has a value between 1 and 4093.
VLAN with limited network access.
Configuring 802.1X and Port-Based Security