question on algorithm for radius based accouting

Hugh Irvine hugh at
Fri Aug 17 05:23:30 UTC 2007

Hello Joe -

The Acct-Session-Time is what the NAS is reporting as the duration of  
the session, and the Acct-Delay-Time is the NAS reporting any delay  
in sending the accounting request (usually due to retransmissions).

The time the accounting request(s) is(are) received by the RADIUS  
server host may or may not be relevant, depending on where the NAS  
and the RADIUS host are located geographically and whether or not the  
time on the RADIUS server host is "correct".

The best approach is to generate an event timestamp which is the time  
the accounting stop is received minus the Acct-Delay-Time (if  
present). The start time is therefore the corrected timestamp minus  
the Acct-Session-Time.

Note that RFC 2869 specifies an Event-Timestamp attribute which is  
meant to indicate the time on the NAS that the accounting event  
occurred, but I have never seen it used.



On 17 Aug 2007, at 11:53, Joe Shen wrote:

> hi,
>    I 'google'  algorithm for radius based accounting.
> but can't find anything.
>   My question is:  what's the best algorithm for
> constrcting  broadband access record from radius
> accouting packets?
>   To my knowledge, some system takes:
>    Record Accouting-on packet arriving time ->
>     record Accouting-Off packet's Acct-Session-Time
> and Acct-Delay-Time  ->
>     The Log-off time is calculated as:
>        Accouting-on time + ( Acct-Session-Time -
> Acct_delay-Time)
>   But, some other takes :
>    Record Accouting-off arriving time -->
>      record Accouting-Off packet's Acct-Session-Time
> and Acct-Delay-Time     -->
>       Log-on time is calculated as:
> Accouting-off arriving time - ( Acct-Session-Time -
> Acct_delay-Time)
>    Are the two methods have the same effect on
> calculating result?  If radius packets were sent to
> two accouting systems simulataneusly, while the two
> system takes the different algorithm, will there be
> any difference between the result of accouting ?
> regards
> Joe
> __________________________________
> Yahoo! Movies - Search movie info and celeb profiles and photos.


Have you read the reference manual ("doc/ref.html")?
Have you searched the mailing list archive ( 
Have you had a quick look on Google (
Have you included a copy of your configuration file (no secrets),
together with a trace 4 debug showing what is happening?
Have you checked the RadiusExpert wiki:

Radiator: the most portable, flexible and configurable RADIUS server
anywhere. Available on *NIX, *BSD, Windows, MacOS X.
Includes support for reliable RADIUS transport (RadSec),
and DIAMETER translation agent.
Nets: internetwork inventory and management - graphical, extensible,
flexible with hardware, software, platform and database independence.
CATool: Private Certificate Authority for Unix and Unix-like systems.

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