Re: Duplicate Entries in Accounting File

Dale E. Reed Jr. (daler@iea.com)
Mon, 24 Jun 1996 15:11:57 -0700

Charles Scott wrote:
>
> Is anyone seeing duplicate entries in their RADIUS accounting file. We
> seem to get on occasion (20 or 30 last month out of some 60,000
> disconnect reccords) dual entries which have the same Acct-Session-Id.
> I'm thinking it may be a lost ACK coming from RADIUS back to the PM
> (perhaps a packet collision), which causes the PM to think the entry
> wasn't received. (is there a 180 second timeout on this?)

There is a three second timeout on the Radius server as far as the
PM is concerned. So if the PM sends the accounting, the server is
really busy and doesn't get back until say five seconds, the PM will
send it again, and again, until it gets a response back within three
seconds. Accounting packates are queued in the PM until a ACK comes
back from the Radius server.

You can see if this is hapenning by looking at the Acct-Delay field
for each packet. Generally it will increase for each packet received
by the Radius server, where the below four fields are the same.

> On a related question, is there any possiblity that two PortMasters
> would produce the same session ID in the period of a month. Is there
> something about the way the ID's are created that prevents this?

Each Accounting Record is unique via these four keys:

NAS-Identifier
NAS-Port
Acct-Session-ID
Acct-Status-Type

We store out accounting into a database and put a unique key contraint
on those, and it prevents the problem you are talking about. There is NO
guranteed uniqeness less than thos four keys. Acct-Session-ID by itself
is not unique.

-- 
Dale E. Reed Jr.  (daler@iea.com)
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