The RADIUS class attribute helps to aid in user identification.
User identification is used to correlate RADIUS accounting messages with the specified user. During the authentication process, the RADIUS authentication server inserts a class attribute into the RADIUS authenticate response message and the router echoes this class attribute in all RADIUS accounting messages.
The 7750 SR can store up to six class attributes for both RADIUS and NASREQ. Each class VSA or AVP can have a maximum of 253 characters. If the VSA or AVP contains more than 253 characters, only the first 253 characters is stored. If there are more than six VSAs or AVPs, only the first six is stored. This functionality is also applicable to RADIUS authentication by the ISA.