(RADIATOR) VoIP Block Time Woes

[Zebaulon Kansal]

Hi,

	I've run into an interesting problem when setting up prepaid
calling card services using VoIP, a Cisco AS5300, and RADIATOR running
on FreeBSD.

	We are wanting to be able to sell prepaid calling cards, with
the card number being the person's home phone number + 4-digit random
number.  We have the Cisco setup something along the lines of this:

call application voice debit tftp://blah.blah/ivr/app_debit.tcl
call application voice deibt language 1 en
call application voice debit set-location en 0 tftp://blah/audio/en/
call application voice debit warning-time 30
call application voice debit uid-len 10
call application voice debit pin-len 4

	We are using a hacked-up version of Block-Time-SQL to make all
this work (basically Block-Time-SQL with modifications to use the Cisco
attributes.)  All of it works fine except for one problem.  Whenever a
caller hangs up, if they have called from their home phone, they end up
being billed double (or triple) the time they used.  I tracked it down
to this problem:

	The access server sends a Stop record for the actual call they
made out over the VoIP network.  Radiator does the appropriate SQL query
to deduct the number of seconds used from their account.  This is what
we want.

	The access server sends another Stop record for the call that
they placed INTO our access server.  The Acct-Session-Time for this one
is the amount of time they were on the call PLUS the time it took them
to enter their card #, etc.  Radiator does the appropriate SQL query to
deduct the number of seconds here from their account also.  Not what we
want.  (Because now they've been deducted TWICE.)  This happens because
their USERNAME entry in the database is equal to their ANI, which is
what the Cisco uses as User-Name on these records.

	If the caller placed a call that was local to the server (some
of our callers are local to the server, but NOT local to places that
the server CAN call local itself) then the server simply creates a VoIP
connection to itself on loopback, and then places the call over the
phone again.  This will generate an additional Stop record for that,
which gets deducted, and well, you see the picture.

	It would be nice if there was a way to filter accounting somehow
so that only ONE time would be deducted.  I tried doing this with a
<Handler> statement, and it doesn't seem to work.  Is there a better way
to filter accounting requests other than Handlers?

	I'll have to look at this one some more in the morning, but I
thought MAYBE someone out there had done this before and could give me
some pointers to save me having to re-invent the wheel. :)  Any ideas
from anyone on how we could do this?  I know, changing the card number
to a totally-random 14 digit would probably fix it, but we'd also like
to (at some point) be able to have people dial in with their home phone,
and simply be prompted for the phone number to call.  After collecting
the digits, it would read back their credit time, and place the call.
So, at that point, their ANI has to be tied to the card somehow...

	Any help/ideas would be appreciated.  Thanks. :)


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