Interlogix NS4702-24P-4S-4X, Руководство пользователя

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seconds haven't expired), the same server will be contacted upon the next
backend authentication server request from the switch. This scenario will loop
forever. Therefore, the server timeout should be smaller than the supplicant's
EAPOL Start frame retransmission rate.
Single 802.1X
In port-based 802.1X authentication, once a supplicant is successfully
authenticated on a port, the whole port is opened for network traffic. This allows
other clients connected to the port (for instance through a hub) to piggy-back on
the successfully authenticated client and get network access even though they
really aren't authenticated. To overcome this security breach, use the Single
802.1X variant.
Single 802.1X is really not an IEEE standard, but features many of the same
characteristics as does port-based 802.1X. In Single 802.1X, at most one
supplicant can get authenticated on the port at a time. Normal EAPOL frames are
used in the communication between the supplicant and the switch. If more than
one supplicant is connected to a port, the one that comes first when the port's link
comes up will be the first one considered. If that supplicant doesn't provide valid
credentials within a certain amount of time, another supplicant will get a chance.
Once a supplicant is successfully authenticated, only that supplicant will be
allowed access. This is the most secure of all the supported modes. In this mode,
the Port Security module is used to secure a supplicant's MAC address once
successfully authenticated.
Multi 802.1X
Multi 802.1X is - like Single 802.1X - not an IEEE standard, but a variant that
features many of the same characteristics. In Multi 802.1X, one or more
supplicants can get authenticated on the same port at the same time. Each
supplicant is authenticated individually and secured in the MAC table using the
Port Security module.
In Multi 802.1X it is not possible to use the multicast BPDU MAC address as
destination MAC address for EAPOL frames sent from the switch towards the
supplicant, since that would cause all supplicants attached to the port to reply to
requests sent from the switch. Instead, the switch uses the supplicant's MAC
address, which is obtained from the first EAPOL Start or EAPOL Response
Identity frame sent by the supplicant. An exception to this is when no supplicants