Interlogix NS3550-2T-8S User Manual - Manual (Page 242)

IFS NS3552-8P-2S AND NS3550-2T-8S User Manual
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are attached. In this case, the switch sends EAPOL Request Identity frames using
the BPDU multicast MAC address as destination - to wake up any supplicants 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 802.1 X-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) for
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].
• RADIUS-Assigned
VLAN Enabled
When RADIUS-Assigned VLAN is both globally enabled and enabled (checked)
for a given port, the switch reacts to VLAN ID information carried in the RADIUS
Access-Accept packet transmitted by the RADIUS server when a supplicant is
successfully authenticated. If present and valid, the port's Port VLAN ID will be
changed to this VLAN ID, the port will be set to be a member of that VLAN ID, and
the port will be forced into VLAN unaware mode. Once assigned, all traffic arriving
on the port will be classified and switched on the RADIUS-assigned VLAN ID.
If (re-)authentication fails or the RADIUS Access-Accept packet no longer carries
a VLAN ID or it's invalid, or the supplicant is otherwise no longer present on the
port, the port's VLAN ID is immediately reverted to the original VLAN ID (which
may be changed by the administrator in the meanwhile without affecting the