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          | SIP Express Media Server  - README |
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Introduction:

 SEMS is a free, high performance, extensible media server 
 for SIP (RFC3261) based VoIP services. 

 It is intended to complement proxy/registrar servers
 in VoIP networks for all applications where server-
 side processing of audio is required, for example away 
 or pre-call announcements, voicemail, or network side 
 conferencing. Another use case is for interconnecting
 SIP networks, where a back-to-back user agent (B2BUA)
 is required.

 SEMS can be used to implement simple high performance 
 components like announcement servers as building 
 blocks of more complex applications, or, using its powerful 
 framework for application development including back-to-back 
 user agent (B2BUA) and state machine scripting functionality, 
 complex VoIP services can be realized completely in SEMS. 
 
 SEMS supports all important patent free codecs out of the
 box (g711u, g711a, GSM06.10, speex, G.726, L16, OPUS, iLBC etc).
 There is a wrapper for the IPP G.729 codec implementation
 available. Integrating other codecs in SEMS is very simple
 (patented or not).

 SEMS shows very good performance on current standard
 PC architecture based server systems. It has sucessfully
 been run with 1200 G.711 conference channels on a quad-core
 Intel(R) Xeon at 2GHz (700 GSM, 280 iLBC channels), and up to 
 5000 channels on a dual quad Xeon at 2.9GHz. Its back-to-back
 user agent has been run with up to 19000 TPS on the latter
 machine. On the other hand it also runs on very small devices -
 for example small embedded systems like routers running OpenWRT,
 for which of course the achievable channel count is not that
 high.

License:

 SEMS is free (speech+beer) software. It is licensed under dual 
 license terms, the GPL (v2+) and proprietary license. This
 program is released under the GPL with the additional exemption
 that compiling, linking, and/or using OpenSSL is allowed.

 For a license to use SEMS under non-GPL terms, please contact
 FRAFOS GmbH at [email protected] .
 
 See doc/COPYING for details.

Applications:

 The following applications are shipped with SEMS :

  Back-to-back User Agent
  
  * sbc            flexible SBC application, supports
                    - identity change
                    - header manipulation (filter etc)
                    - (multihomed) RTP relay, NAT handling, transcoding
                    - SIP authentication 
                    - Session timer, call timer, prepaid
                    etc

 Announcements (Prompts, Ringbacktones, Pre-call-prompts):
  * announcement   plays an announcement


  * ann_b2b        pre-call-announcement, plays announcement 
                   before connecting the callee in B2BUA mode
 
  * announce_transfer  pre-call-announcement, plays announcement 
                   and then transfers the caller to the callee 
                   using REFER

  * early_announce (pre-call) announcement using early media (183),
                   optionally continues the call in B2BUA mode

  * precoded_announce plays preencoded announcements


 Voicemail/Mailbox
  * voicebox       users can dial in to the voicebox to check
                   their messages

  * annrecorder    users can record their personal greeting 
                   message

  * mailbox        auto-attendant that saves voicemails into
                   an IMAP server. Users can dial in to check
                   their messages (simpler version)

  * voicemail      records voice messages and sends them 
                   as email, saves them to a voicebox, or
                   both


 Conferencing

  * conference     enables many people to talk together 
                   at the same time

  * webconference  conference application that can be 
                   controlled from an external program, 
                   e.g. a website 

  * conf_auth      collect a PIN number, verify it against an 
                   XMLRPC authentication server and connects in 
                   B2BUA mode

  * pin_collect    collect a PIN, optionally verify it, and transfer
                   the call into a conference

 App development

  * dsm            DSM state machine scripting (use this)

  * ivr            embedded Python interpreter for simple apps
  
  * py_sems        another embedded Python interpreter

 Misc
  * echo           test module to echo the caller's voice
 

  * callback       reject the call, call back caller later and have 
                   her enter a number to call in b2bua with media relay
                   mode

  * reg_agent     SIP REGISTER to register SEMS' contact to an aor


Developing and customizing Applications and services:

 SEMS comes with a set of example applications intended to help 
 development of custom services, including a calling card 
 application, a traffic generator, a component to control the 
 media server via XMLRPC, and announcements played from DB.

 DSM state machine scripting is a powerful yet simple method
 to rapidly implement custom applications. With this method,
 the service logic is written as an easy to understand 
 textual definition of a state machine, which is interpreted
 and executed for every call. The (domain specific) language 
 for defining state machines can be extended by implementing
 modules. A set of useful modules are shipped with SEMS, 
 including MySQL database access module, Python module, 
 conference support, Amazon AWS and more. 

 SEMS' core implements basic call and audio processing, 
 and loads plug-ins which extend the system. Audio
 plug-ins enable new codecs and file formats, 
 application plug-ins implement the services' logic.
 Other modules called component modules provide 
 functionality for other modules to use.

 You can easily extend SEMS by creating your own plug-ins.
 Applications can be written using the SEMS framework API 
 in C++, or in Python using an embedded python interpreter 
 of the ivr or py_sems modules, or the DSM.

Requirements:

 All requirements are optional.

 o Python for the ivr (embedded python interpreter) and py_sems
 o flite speech synthesizer for TTS in the ivr
 o lame >= 3.95 for mp3 file output, mpg123 for mp3 playback
 o spandsp library for DTMF detection and PLC
    (SEMS has its own implementations for both)
 o libZRTP SDK (http://zfoneproject.com) for ZRTP
 o libev for jsonrpc

Supported environments:

  SEMS server hes been tested with the following:
    * RHEL 7 with Python 3
    * RHEL 8 with Python 3
    * RHEL 9 with Python 3
    * Debian 11 with Python 3
    * Debian 12 with Python 3

  Please see appropriate Dockerfiles

Creating packages on debian (ubuntu, ...):

   install debian package build tools:
   $ sudo apt-get install debhelper devscripts

   install dependencies (those below or let dpkg-buildpackage below tell you
   which ones):
   $ sudo apt-get install debhelper g++ make libspandsp-dev flite1-dev \
         libspeex-dev libgsm1-dev libopus-dev libssl-dev python-dev \
	 python-sip-dev openssl libev-dev libmysqlcppconn-dev libevent-dev \
	 libxml2-dev libcurl4-openssl-dev libhiredis-dev
   
   get the source: 
   $ git clone https://github.com/sems-server/sems.git

   $ cd sems; ln -s pkg/deb/buster ./debian

   set version in changelog if not correct
   $ dch -v x.y.z "SEMS x.y.z release"
   or:
   $ dch -b -v `git describe --always` "sems git master"
   
   build package:
   $ dpkg-buildpackage -rfakeroot -us -uc

   install sems and sems-python-modules packages in .. using dpkg.

Build and run in container

   # build
   docker build -t sems-rhel8 -f Dockerfile-rhel8
   # test-run in foreground
   podman run --rm -it --name sems sems-rhel8

Installed files using 'make install':

    /usr/local/sbin/sems                 : SEMS executable
    /usr/local/lib/sems/plug-in/*        : plug-ins
    /usr/local/lib/sems/audio/*          : default path for audio files
    /usr/local/lib/sems/ivr/*            : precompiled IVR scripts
    /usr/local/etc/sems/sems.conf        : configuration file
    /usr/local/etc/sems/etc/*            : modules configuration files
    /usr/local/share/doc/sems/README     : this README.

    source_path/scripts/sems[.redhat]    : example start-up scripts.
    source_path/sems.conf.example        : example configuration file.

Documentation:

  In the doc/ directory there is a set of files describing the
  applications shipped with SEMS, alongside some more documentation.
  Generate the doxygen documentation with 'make doc' in doc/doxygen_doc,
  that contains all these files as well.

Support, mailing lists, bugs and contact:

  Best-effort support is given through the mailing lists for SEMS,
  [email protected] and [email protected], which are the
  first address to ask for help, report bugs and improvements.

  Bugs can be filed as issues on this site.  Please submit all bugs,
  crashes and feature requests you encounter.

Authors:

  Raphael Coeffic ([email protected]), the father of SEMS, 
  Stefan Sayer ([email protected]), current lead developer,
  and all contributors:
    Alex Gradinar
    Alfred E Heggestad
    Andreas Granig
    Andrey Samusenko
    Andriy I Pylypenko
    Anton Zagorskiy
    B. Oldenburg
    Balint Kovacs
    Bogdan Pintea
    Carsten Bock
    Greger Viken Teigre
    Grzegorz Stanislawski
    Helmut Kuper
    Jeremy A
    Jiri Kuthan
    Joe Stusick
    Jose-Luis Millan
    Juha Heinanen
    Matthew Williams
    Michael Furmur
    Ovidiu Sas
    Pavel Kasparek
    Peter Lemenkov
    Peter Loeppky
    Richard Newman
    Robert Szokovacs
    Rui Jin Zheng
    Tom van der Geer
    Ulrich Abend
    Vaclav Kubart
    Victor Seva
   (if you feel you should be on this list, please mail to [email protected])
 
  Special thanks to FRAFOS GmbH, sipwise GmbH, IPTEGO GmbH, iptelorg GmbH and TelTech Systems Inc. for 
  sponsoring development of SEMS.

Contributions:

  All kinds of contributions and bug fixes are very welcome, for 
  example new application or codec modules, documentation pages, howtos
  etc. Please email one of the lists or the authors.

  Please also have a look at the contributions license policy 
  (see doc/COPYING).
  
SEMS - the media-S in the SLAMP.