Publication date: June, 2015
Revision A1
that might be on the port.
The maximum number of supplicants that can be attached to a port can be limited using the
Port Security Limit Control functionality.
MAC-based Auth.:
Unlike port-based 802.1X, MAC-based authentication is not a standard, but merely a
best-practices method adopted by the industry. In MAC-based authentication, users are
called clients, and the switch acts as the supplicant on behalf of clients. The initial frame (any
kind of frame) sent by a client is snooped by the switch, which in turn uses the client's MAC
address as both username and password in the subsequent EAP exchange with the RADIUS
server. The 6-byte MAC address is converted to a string on the following form
"xx-xx-xx-xx-xx-xx", that is, a dash (-) is used as separator between the lower-cased
hexadecimal digits. The switch only supports the MD5-Challenge authentication method, so
the RADIUS server must be configured accordingly.
When authentication is complete, the RADIUS server sends a success or failure indication,
which in turn causes the switch to open up or block traffic for that particular client, using the
Port Security module. Only then will frames from the client be forwarded on the switch.
There are no EAPOL frames involved in this authentication, and therefore, MAC-based
Authentication has nothing to do with the 802.1X standard.
The advantage of MAC-based authentication over port-based 802.1X is that several clients
can be connected to the same port (e.g. through a 3rd party switch or a hub) and still
require individual authentication, and that the clients don't need special supplicant software
to authenticate. The advantage of MAC-based authentication over 802.1X-based
authentication is that the clients don't need special supplicant software to authenticate. The
disadvantage is that MAC addresses can be spoofed by malicious users - equipment whose
MAC address is a valid RADIUS user can be used by anyone. Also, only the MD5-Challenge
method is supported. The maximum number of clients that can be attached to a port can be
limited using the Port Security Limit Control functionality.
RADIUS-Assigned QoS Enabled :
When RADIUS-Assigned QoS is both globally enabled and enabled (checked) on a given
port, the switch reacts to QoS Class information carried in the RADIUS Access-Accept packet
transmitted by the RADIUS server when a supplicant is successfully authenticated. If present
and valid, traffic received on the supplicant's port will be classified to the given QoS Class. If
(re-)authentication fails or the RADIUS Access-Accept packet no longer carries a QoS Class
or it's invalid, or the supplicant is otherwise no longer present on the port, the port's QoS
Class is immediately reverted to the original QoS Class (which may be changed by the
administrator in the meanwhile without affecting the RADIUS-assigned).
This option is only available for single-client modes, i.e.
• Port-based 802.1X
• Single 802.1X
RADIUS attributes used in identifying a QoS Class:
Refer to the written documentation for a description of the RADIUS attributes needed in
order to successfully identify a QoS Class. The User-Priority-Table attribute defined in
RFC4675 forms the basis for identifying the QoS Class in an Access-Accept packet.
Only the first occurrence of the attribute in the packet will be considered, and to be valid, it
must follow this rule:
• All 8 octets in the attribute's value must be identical and consist of ASCII characters in the
range '0' - '3', which translates into the desired QoS Class in the range [0; 3].
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