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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 9 Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
IEEE 802.1x Accounting
The IEEE 802.1x standard defines how users are authorized and authenticated for network access but
does not keep track of network usage. IEEE 802.1x accounting is disabled by default. You can enable
IEEE 802.1x accounting to monitor this activity on IEEE 802.1x-enabled ports:
• User successfully authenticates.
• User logs off.
• Link-down occurs.
• Re-authentication successfully occurs.
• Re-authentication fails.
The switch does not log IEEE 802.1x accounting information. Instead, it sends this information to the
RADIUS server, which must be configured to log accounting messages.
IEEE 802.1x Accounting Attribute-Value Pairs
The information sent to the RADIUS server is represented in the form of Attribute-Value (AV) pairs.
These AV pairs provide data for different applications. (For example, a billing application might require
information that is in the Acct-Input-Octets or the Acct-Output-Octets attributes of a RADIUS packet.)
AV pairs are automatically sent by a switch that is configured for IEEE 802.1x accounting. Three types
of RADIUS accounting packets are sent by a switch:
• START–sent when a new user session starts
• INTERIM–sent during an existing session for updates
• STOP–sent when a session terminates
Table 9-1 lists the AV pairs and when they are sent are sent by the switch:
Tab l e 9-1 Accounting AV Pairs
Attribute Number AV Pair Nam e START INTERIM STOP
Attribute[1] User-Name Always Always Always
Attribute[4] NAS-IP-Address Always Always Always
Attribute[5] NAS-Port Always Always Always
Attribute[8] Framed-IP-Address Never Sometimes1Sometimes1
Attribute[25] Class Always Always Always
Attribute[30] Called-Station-ID Always Always Always
Attribute[31] Calling-Station-ID Always Always Always
Attribute[40] Acct-Status-Type Always Always Always
Attribute[41] Acct-Delay-Time Always Always Always
Attribute[42] Acct-Input-Octets Never Never Always
Attribute[43] Acct-Output-Octets Never Never Always
Attribute[44] Acct-Session-ID Always Always Always
Attribute[45] Acct-Authentic Always Always Always