Re: [Help-gnu-radius] Acct-Session-Time

[Thomas C Kinnen]

On Tue, 12 Nov 2002, Kurt Tragant wrote:

> Hello list,
>
> I've got the problem, that the time of session is not correct. For
> example, I've got a session from 00:36:14 until 01:21:47 = 2733 seconds.
> Radius says, that this session was 2332 seconds. I've attached the text
> output of radius below. For answers I thank you in advance...

While the time difference is big this is not unexpected due to the way the
RADIUS protocol works.  The Acct-Session-Time is how long the session
lasted.  It has nothing to do with when the RADIUS client decided to send
the packets to the server or the time stamp in the server's log.  While
using the time stamp in the accounting record is usefull for making sure
things are in the right range they very often are not the same as the
session time.  Remember the RADIUS client is not required to insert
Acct-Delay-Time if the packet is in the queue for a while.  Some clients
do not update this as it requires a new identifier and authenicator.
Even the RFC stats that this just lets you find the "approximate" time the
event happened.  The only way to be for sure when an event happens is if
the packet includes Event-Timestamp (RFC 2869) and you have NTP running.

Tom


-- 
Thomas C Kinnen - RADIUS Engineer - LUCENT Technologies INS
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