Snom 4S Media Server Use and care manual

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4
S
Administrator‘s
Manual
snom 4S
Calling Card System
Version 1.00
snom 4S Calling Card Application Chain
PSTN Network
SIP User Agents
snom 105
Softphone
snom 200
snom 4S
Registrar/Proxy
4
S
snom 4S
Media Server
4
S
SIP/PSTN
Gateway
Breakout
© 2004 snom technology AG
Application Server


snom technology AG • 3
snom 4S Calling Card System Version 1.00
Administrator Manual
1. Edition 2004
© 2004 snom technology Aktiengesellschaft. All Rights Reserved.
This document is supplied by snom technology AG for information purposes only to licensed
users of the snom 4S Calling Card´s Module and is supplied on an “AS IS” basis, that is,
without any warranties whatsoever, express or implied.
Information in this document is subject to change without notice and does not represent any
commitment on the part of snom technology AG. The software described in this document
is furnished under a license agreement and may be used only in accordance with the terms
of that license agreement. It is against the law to copy or use this software except as
specically allowed in the license. No part of this document may be reproduced, republished
or retransmitted in any form or by any means whatsoever, whether electronically or
mechanically, including, but not limited to, by way of photocopying, recording, information
recording or through retrieval systems, without the express written permission of snom
technology AG.

snom technology AG • 3
Table of Contents
1. Overview ................................................................5
2. Usage Scenario.......................................................7
3. Components ...........................................................9
3.1. SNOM 4S Proxy/Registrar .................................................... 10
3.2. SNOM 4S Mediaserver......................................................... 10
3.3. The Application Server ........................................................ 10
The Web Server.................................................................................................................................................................................... 11
The Database Server..................................................................................................................................................................... 11
The Application Logic.................................................................................................................................................................... 12
4. Installation...........................................................13
4.1. Installing the SNOM 4SProxyRegistrar ................................... 13
The Proxy Script................................................................................................................................................................................... 13
4.2. Installing the SNOM 4S Mediaserver ..................................... 18
Creating the Calling Card Account............................................................................................................................. 18
4.3. Installing the Application Server ........................................... 19
Installing the Web server ....................................................................................................................................................... 20
Installing the Database Server and the Calling Card database....................................... 21
Installing the Scripts ..................................................................................................................................................................... 25
5. Conguration .......................................................27
5.1. Conguring the interface between Proxy/Registrar and
Mediaserver ............................................................................. 27
Conguring the Dial Plan......................................................................................................................................................... 27
5.2. Conguring the interface between SNOM 4S Mediaserver and
Application Server..................................................................... 29
The HTTP GET interface ............................................................................................................................................................ 29
The XML state script ...................................................................................................................................................................... 30
6. Administering the Calling Card System.................33
6.1. Generating new Calling Cards .............................................. 33

4 • Table of Contents
[ S N O M 4S CALLING C A R D S YSTEM A D M I N I S T R A T O R M ANUAL ]
snom technology AG • 5
6.2. Setting rates...................................................................... 34
6.3. Viewing card or rate information........................................... 34
Footnotes ................................................................................ 35
Index .......................................................................37

4 • Table of Contents
[ S N O M 4S CALLING C A R D S YSTEM A D M I N I S T R A T O R M ANUAL ]
snom technology AG • 5
1
1. Overview
The SNOM 4S Calling Card (S4SCC) Module integrates the SNOM
4S Registrar/Proxy, the SNOM 4S Mediaserver and a back-end application
server to provide a fully-edged calling card system for pre-paid VoIP-to-
PSTN telephony.
It provides:
• PIN-based authentication and authorization
• Real-time accounting of calls.
• Customizable Interactive Voice Response (IVR) with full
multi-language support1
• Automatic generation of calling cards
• Web-based administration GUI
The S4SCC is accessed by registering with the SNOM 4S Proxy/
Registrar (S4SPR). The S4SPR handles primary authentication and keeps
track of all active users.
At the core of the calling card system lies the SNOM 4S
Mediaserver (S4SMS). The S4SMS is a versatile media server, which
provides media encoding/decoding as well as sophisticated back-to-back
user agent (B2BUA) functionality.
The S4SMS exposes a scriptable state engine, through which the
CC service can be adapted to individual needs.
At the end of the application chain lies an SIP/PSTN gateway,
which is external to the system. Any RFC3261-compliant SIP/PSTN
gateway is suitable.

6 • Overview
[ S N O M 4S CALLING C A R D S YSTEM A D M I N I S T R A T O R M ANUAL ]
snom technology AG • 7
1

6 • Overview
[ S N O M 4S CALLING C A R D S YSTEM A D M I N I S T R A T O R M ANUAL ]
snom technology AG • 7
2
2. Usage Scenario
End-Users of the S4SCC system buy a telephone card with a 12-
digit card ID and a secret 4-digit PIN. They access the system with an
S4SCC-compliant SIP user agent (SUA).
The client needs to register with the calling card operator’s SIP
domain, using the card ID as the SIP user name and the PIN as the SIP
password.
Example:
Operator’s SIP domain: cccall.com
IP address of SIP registrar in charge of cccall.com: 123.123.123.123
Card number: 123456789012
PIN: 1234
Register Command
REGISTER sip:123.123.123.123 SIP/2.0
From: <sip:[email protected]>;tag=XXXX
To: <sip:[email protected]>
....
Upon receiving this REGISTER request, the registrar sends back
an
SIP/2.0 407 Proxy Authentication Required
The user enters his password (alternatively, he may have
precongured it with his SUA) and the SUA re-sends the REGISTER
request with the required authentication information. If the authentication
information matches the database of valid and active calling cards, the
registrar sends back a
SIP/2.0 200 OK

8 • Usage Scenario
snom technology AG • 9
2
Via:....
From: <sip:[email protected]>;tag=XXXX
To: <sip:[email protected]>
X-SNOM-CCTOKEN: 98765432
This response contains a proprietary “token”2, which provides
the SUA with a secure way of accessing the S4SCC without needing to
re-authenticate at each request. The token is valid for the duration of the
registration. Upon re-registering, a new token is issued. The client needs to
be compliant with this protocol extension.
Once the registration sequence described above has been
completed, the user can place calls, which will be charged to his calling
card.
The S4SCC application server backend contains a rate table that
determines which country and city codes can be accessed and how much
they cost. Each calling card is assigned to one rate table in order to allow
the operator to offer different cards with different pricing models.
The user places a call by dialing the telephone number of
his (PSTN) counterpart. The S4SCC will verify that this is a reachable
destination and establish the connection via the SIP/PSTN breakout
gateway.
Accounting starts after the media connection between SUA and
PSTN counterpart has been established.
The SNOM 4S Mediaserver at the core of the system goes through
a state transition after each billing period. Based on this transition, the
accounting database is updated and real-time balance information is
sent to the SUA3. All accounting and billing is based on this real-time
accounting information.

8 • Usage Scenario
snom technology AG • 9
3
3. Components
The main components have already been described. The following
image shows their interaction.

10 • Components
[ S N O M 4S CALLING C A R D S YSTEM A D M I N I S T R A T O R M ANUAL ]
snom technology AG • 11
[ S N O M 4S CALLING C A R D S YSTEM A D M I N I S T R A T O R M ANUAL ]
3
3.1. SNOM 4S Proxy/Registrar
The S4SPR acts as the authentication and authorization gateway
to the system. Its user information needs to be synchronized with the
user database in the application server.
It forwards all authenticated calls to the media server, which
is congured through the dial plan. The token-based authentication/
authorization is congured using a proxy script.
The actual settings and scripts will be described in the
“Conguration” section.
3.2. SNOM 4S Mediaserver
The calling card system core component is a special B2BUA within
the media server4. It is based on the model of a state machine, which can be
scripted through a simple XML-based conguration language.
Although it is based on a state machine model, it is stateless in that
it keeps no call state in its memory space5.
All call state is kept in the application server (AS; see below). The
Mediaserver interacts with the AS through simple HTTP GET requests. It
initializes state for each call through a request to
http://<application_server>/cc/cc_init.php.
This request generates a session ID and passes it back to the Calling
Card B2BUA. This session ID is used in all interactions with the application
server.
3.3. The Application Server
The application server consists of:
1. A web server (Apache)
2. A database server (MySQL)