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How to set up the proxy for voicemail and voicebox in SEMS
Introduction
This text describes how one can set up a SER based home proxy SIP proxy
with voicemail and voicebox service implemented in SEMS.
With minor modifications, this should work with home proxies
implemented with SER derivatives ([8]Kamailio 1.x, [9]OpenSIPS), and
also with [10]sip-router (e.g. Kamailio 3.0) based proxy
configurations. For other types of proxies or SIP platforms, it should
give an idea of what is required to use a SEMS based voicemail system.
Features of a voicemail system with SEMS
The voicemail system that comes with SEMS supports the following
features
* voicemail2email and/or dial-in voicebox
* greeting only mode
* voicebox plays message count
* new and saved messages
* user can record personal greeting message (as a separate service
number)
* multi-domain capable
* multi-language capable (e.g. as user setting), supports
single-digits pre and post
* supports domain and user aliases (domain/user string or domain-ID
(DID)/user-ID (UID) )
* prompts per domain/language
* default greeting message per domain/language
* configurable key bindings for menu
Parameters to voicemail applications
Usually, when a call should be sent to the voicemail system, the home
proxy already knows some parts or all of the user profile, for example
the email address of a user, or the voicemail settings; for example the
user profile is already loaded from a DB (or LDAP, RADIUS, DIAMETER
etc). For this reason, in a SEMS based voicemail system, the proxy adds
the relevant information as parameters to the INVITE request. Those
parameters are set in the P-App-Param header.
Example:
INVITE sip:1000@sems01.iptel.org:5080 SIP/2.0.
From: "sayer@iptel" <sip:sayer@iptel.org>;tag=d3olt2dqvl.
To: <sip:1000@iptel.org>.
...
P-App-Name: voicebox.
P-App-Param: usr=sayer;dom=iptel.org;lng=en;uid=3ab0a114-ceff-11da-8607-000
2b3abca3a;did=2f2091f5-ceff-11da-8220-0002b338cf3a;.
If the proxy does not support this, or does not have access to the user
profile, there are two solutions:
* add another SER-based proxy in front of SEMS that has access to
user profile, and adds those headers
* add the functionality for accessing the user profile to SEMS (e.g.
access DB in SEMS)
For both solutions, the main complexity lies in the fact that the right
user needs to be identified (with support for multi domain, aliases,
call forwarding etc).
Features of a voicemail system with SEMS
There is three applications involved in a voicemail/voicebox system in
SEMS: voicemail, voicebox and annrecorder. Voicemail is the application
that records a message, and sends the message as email or stores it
into the voicebox storage. Voicebox is the application that users can
dial into, listen to their messages, delete or save them. Annrecorder
is an application that lets users record their personal greeting
message.
If only voicemail2email is to be used, the voicemail application alone
can be employed. In that case, the mode must be set to voicemail (see
voicemail application parameters below).
Storage for voice message files and greetings
The storage for voice messages is implemented in a separate module.
This way for example a specialized adapter to some replicated storage
system can be implemented and loaded without changing the other
applications.
A storage module only needs to support a few very simple functions:
Create, get and delete messages, mark a message as read, list a user's
directory, and get the number of messages in the user's directory. The
sender and the message record time is encoded in the message name.
The default storage module, msg_storage, is an implementation that just
uses the normal file system calls (fopen(), readdir(), opendir() etc).
As 'saved' flag, the mtime of the file is compared to the atime.
Note:
If your file system does not support atime, this will not work,
i.e. all messages will always appear as unread!
Domain/User text or domain ID (DID) and user ID (UID)
If the platform supports user and domain aliases (e.g. sip.iptel.org
and iptel.org, or numeric aliases), there may not be a canonical user
name available. For that case, the user ID and domain ID (canonical
user/domain ID) may be used, by setting UID/DID application parameters.
This overrides the user name and domain name, so that the correct user
and domain is identified.
Voicemail application modes
The voicemail application has four modes:
* voicemail : send email (default)
* box : leave in voicebox (store in msg_storage)
* both : send email and leave in voicebox
* ann : just play greeting, don't record message.
For voicemail and both mode, the email address must be given as
parameter.
Voicemail specific AVPs
The following user AVPs should be configured in SerWeb to be
user-configurable:
* voicemail : voicemail mode - 'voicemail', 'box', 'both', or 'ann'
* email: email address
* lang: language - selectable from those for which prompts are
present
Proxy configuration for ser-oob.cfg
These route fragments could be inserted into a typical ser-oob or
default Kamailio configuration.
Leaving a message
This should be added to native SIP destinations which are not found in
usrloc, i.e. instead of replying 480 User temporarily not available,
and in FAILURE_ROUTE:
append_hf("P-App-Name: voicemail\r\n");
append_hf("P-App-Param: mod=%$t.voicemail%|;eml='%$t.email%|';usr=%@ruri.
user%|;snd='%@from.uri%|';dom=%@ruri.host%|;uid=%$t.uid%|;did=%$t.did%|;");
rewritehostport("voicemail.domain.net:5080");
route(FORWARD);
Calling voicebox
This should be added to SITE-SPECIFIC route:
if (uri=~"^sip:1000") { # 1000 is voicebox access number
append_hf("P-App-Name: voicebox\r\n");
append_hf("P-App-Param: usr=%@from.uri.user%|;dom=%@from.uri.host%|;lng
=%$f.lang%|;uid=%$f.uid%|;did=%$f.did%|;\r\n");
rewritehostport("voicemail.domain.net:5080");
route(FORWARD);
}
Recording the greeting
This is very similar to the one above, and should be added to
SITE_SPECIFIC as well:
if (uri=~"^sip:1001") { # 1001 is recod greeting number
append_hf("P-App-Name: annrecorder\r\n");
append_hf("P-App-Param: usr=%@from.uri.user%|;dom=%@from.uri.host%|;lng
=%$f.lang%|;uid=%$f.uid%|;did=%$f.did%|;typ=vm;\r\n");
rewritehostport("voicemail.domain.net:5080");
route(FORWARD);
}
Note the type (typ) here; the annrecorder application can be used to
record different greetings (e.g. away greeting when recording message,
or normal away greeting). This type can be used when sending a call to
voicemail application.
__________________________________________________________________
Generated on Thu Feb 3 02:29:25 2011 for SEMS by [11]doxygen 1.6.1
References
1. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/index.html
2. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/pages.html
3. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/namespaces.html
4. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/annotated.html
5. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/files.html
6. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/dirs.html
7. file://localhost/home/stefan/devel/sems/sems/doc/doxygen_doc/html/examples.html
8. http://kamailio.org/
9. http://opensips.org/
10. http://sip-router.org/
11. http://www.doxygen.org/index.html
