Configuration guidelines

The periodic online user re-authentication timer can also be set by the authentication server in the session-timeout attribute. The server-assigned timer overrides the timer setting on the access device, and enables periodic online user re-authentication, even if the function is not configured. Support for the server assignment of re-authentication timer and the re-authentication timer configuration on the server vary with servers.

The VLAN assignment status must be consistent before and after re-authentication. If the authentication server has assigned a VLAN before re-authentication, it must also assign a VLAN at re-authentication. If the authentication server has assigned no VLAN before re-authentication, it must not assign one at re-authentication. Violation of either rule can cause the user to be logged off. The VLANs assigned to an online user before and after re-authentication can be the same or different.

If no critical VLAN is configured, RADIUS server unreachable can cause an online user being re-authenticated to be logged off. If a critical VLAN is configured, the user remains online and in the original VLAN.