I have been looking at this, and scratching my head. It appears as if the (timestamp -(minus) acct-delay-time) does not always = the actual start time of the session. From my observation, and log reading script, I have found that there could be a +/- 1 second variance in either the timestamp, or the acct-delay-times. Could this be the router sending it's time, and the radius box intercepting it at a possible rounding up or down to the next second? Is there a way to use the microseconds to ensure that these values are accurate all the time? Basically, what I am trying to achieve, is that when I insert into my 'MySQL' database that it's updating the proper start record on 'Interim-Update' or 'Stop' records, and not creating a new start record for it when it's just off by 1 second or so. Is there possibly a better way to create a unique key, rather than what I am currently using as a unique group of fields: Framed-ip-address + nas-ip-address + user-name + acct-session-id + ((timestamp - acct-delay-time) - acct-session-time) Steven Staples