Questions on Acct-Interim-Interval

David Roze david at
Tue Oct 2 22:38:57 CEST 2007


>-----Original Message-----
>From: freeradius-users-bounces at
[mailto:freeradius->users-bounces at] On Behalf Of Vinay
>Sent: 02 October 2007 20:47
>To: FreeRadius users mailing list
>Subject: Questions on Acct-Interim-Interval
>A couple of questions on Acct-Interim-Interval
>1. I wanted to know if the Acct-Interim update that comes from the NAS has
>any relevance as far as the user session maintained in the radius server is
>concerned. Meaning that is it treated like a keep-alive of some sort. If
>Acct-Interim-Interval is configured to be 100 seconds and the NAS sends the
>Interim-Update after 200 seconds does the freeradius server care ?

Acct-Interim-Update is an extrension to the Radius protocol to make it more
robust for people who do accounting. It avoids losing the totallity of your
session accounting if the stop record gets lost (or the NAS becomes
Not a keep-alive really...

>2. What is the typical value of this attribute, I ask because if this value
>is configured to be small then it will generate a lot of interim updates
>from a NAS that supports large number of subscribers. At the same time I am
>not sure how the service providers who deploy the server use this Attribute
>and how often do they want the updates.

Interim updates increase the load on the NAS, especially with a lot of
sessions. 100s sounds very short and could impact your authentication
I would send every 60mn or more. Anyone's tried below with a lot of
subscribers maybe?

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David Roze

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