Nortel Networks Mediant TP-1610 SIP - Manual (Page 248)

Mediant 2000 SIP
Mediant 2000 SIP User’s Manual 248 Document #: LTRT-72504
K.4.2 Call Flow Description
Figure K-2 on the previous page depicts an example of a standard PSTN IP call (billing-model:
debit).
• An incoming PSTN call with a published access number reaches the Mediant 2000.
• The Mediant 2000 accepts the call (sends an Alert message).
• The Mediant 2000 searches its internal Tel IP Destination Number Manipulation table for
the specific prefix. When it is detected, if the ‘Prefix to Add’ column corresponds to the
predefined VXMLID parameter (in the example below: http), the Mediant 2000 determines
that the incoming call is an IVR call.
Figure K-3: Basic ini File VXML Parameters
VXMLID = http
NumberMapTel2IP = 5394288,7,http://10.8.1.19/RadAAA01.txt
• The Mediant 2000 loads the VoiceXML file (RadAAA01.txt) from an outbound HTTP Server
(10.8.1.19) and stores it in its volatile memory. In
Figure K-2 it is assumed that the VoiceXML
already resides in the Mediant 2000.
• The Mediant 2000 sends an Answer/Connect message.
Note: The following steps are according to the supplied VXML script.
• The Mediant 2000 starts by playing an initial voice message. This message is composed of
an opening greeting and an interactive menu asking the caller to choose one of the following
options: 1 to make a call, 2 for help, 3 for operator service, 4 to exit.
• After pressing the digit 1, the caller is immediately prompted to enter his account number
(usually the card number) and his password or PIN (personal identification number). The
Mediant 2000 collects the input DTMF digits and sends an Authentication message to an
outbound RADIUS server.
• Only after the call is authenticated successfully (in this stage the RADIUS server returns the
billing-model, in the above example: debit), the caller is asked to enter the number he wishes
to reach, the final destination number. The gateway collects the input DTMF digits and sends
an Authorization message to the RADIUS server.
• The RADIUS server determines if the caller is authorized to proceed with the call and
specifies the maximum duration of the call; the Mediant 2000 conveys the call to the IP
network and starts an internal timer.
• One minute before credit is exhausted (refer to the VXML parameter finalalerttime on page
260 ); the finalalertaudio is played; finally, a minute later, the call is disconnected and the
endaudio Voice Prompt is played.
• After the conclusion of the call, the Mediant 2000 sends an Accounting message to the
RADIUS server containing the call details (CDR) and prompts the user either to proceed with
another call or to disconnect.