I noticed looking through the commits in FreeRADIUS 3.1 that the Acct-Unique-Session-Id is now using the Acct-Multi-Session-Id in its construction. Awesome! :) I wondered while looking at the commit if there has been consideration about dropping the NAS-Port in the construction so that FreeRADIUS interoperates, in its default configuration, with wireless controllers that keep the same Acct-Session-Id when a roam occurs from one BSS/AP to another BSS/AP? In that scenario, it is, of course, the controller that is the NAS, not the APs. Some controllers set the value of the NAS-Port attribute on per AP or BSS basis and this therefore changes where a roam occurs. In my opinion, vendors should be sending a Stop and a Start when a roam occurs with a constant Acct-Multi-Session-Id being used to allow sessions to be correlated, but this not the case today. This has been written about by others too: http://daniele.albrizio.it/how-to_/freeradiusacct-unique-session-idfix I was looking in to this area of FreeRADIUS more closely as I have been engaging with Aerohive on their Acct-Session-Ids. The upcoming HiveOS releases will have Acct-Session-Ids that have the properties of a GUID/UUID. At the moment, they're just incremented and are therefore not guaranteed to be unique across reboots. Cheers, Nick Lowe