SKYPIAX,

1

• SKYPIAX,
• how to add Skype capabilities
• to FreeSWITCH (and Asterisk)
• CHICAGO, USA, September 2009

2
AGENDA

• Overview
• How it Works
• Usage
• How to build it
• How to Configure it
• Starting it
• CLI commands
• Performances
• QA

3
SKYPIAX important infos

• Skypiax uses the Skype API but is not endorsed,
  certified or otherwise approved in any way by
  Skype, Ebay, or any other company owning rights
  to the Skype technology
• Skypiax is developed mainly on FreeSWITCH, and is
  then made to be compatible with Asterisk too
  (occasionally Asterisk version can lag behind or
  not compile straight from svn. Asterisk users, be
  patient or volunteer to maintain)

4
WHAT is SKYPIAX ?

• Skypiax is an endpoint (channel driver) that uses
  the Skype client as an interface to the Skype
  network, and allows incoming and outgoing Skype
  calls to/from FreeSWITCH (calls can be bridged,
  originated, answered, etc. as in all other
  endpoints, e.g. sofia/SIP).
• Skypiax works in FreeSWITCH (FS) on both Linux
  and Windows (directly, no Cygwin needed), native
  at 16khz (Skype client has 16khz audio I/O).
• Skypiax works on Asterisk too, converting at 8khz
  (Asterisk cannot do 16khz), on Linux and Windows
  (through CygWin).
• Think of Skypiax as similar to OpenZAP for analog
  lines. For each channel you need an interface (a
  Skype client). So, for example, two concurrent
  calls would need two channels, and therefore two
  Skype clients running on your FreeSWITCH server.

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SKYPIAX Features Overview

• Multiline (many concurrent different
  skypeusernames Alice, Bob, ... Zukowski)
• Multiline (many concurrent instances of the same
  skypeusername Alice, Alice, .... Alice)
• Multiline (a mix of the former two setups)
• Can make SkypeOut calls to PSTN and cellphones
• Easy integration into dialplan (like standard
  endpoints)
• Round Robin or Linear hunt for next available
  outbound channel
• Automatic selection of interface to answer
  incoming call
• CLI commands for statistics, debug, prototyping,
  control
• Easy interaction with the outside world through
  ESL or AMI

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SKYPIAX, how it works

• One Skype client instance running per each
  Skypiax interface (eg 32 Skype concurrent calls,
  32 Skypiax interfaces, 32 Skype clients running)
• Skypiax remote controls its own configured
  Skype client via Skype API
• Skypiax exchange audio to/from the Skype client
  via TCP/IP sockets (activated via Skype API) that
  substitute the soundcard microphone and speakers

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Skype API, what it looks like

• Skype API is a proprietary, text based protocol
  for communication between the Skype client and
  other external software (eg Skypiax)?
• On Windows is implemented through Windows
  Messages, on Linux using X Events
• For both Linux and Windows, Skypiax creates a
  fake window with its own message loop, then
  dispatch messages to the monitor or to the
  appropriate interface thread
• Eg Skypiax sends PING to Skype client, Skype
  client sends PONG back to Skypiax
• Skype API is fairly complete, can manage calls,
  call progress, messaging, etc
• Skypiax gives you different tools for interacting
  at the Skype API level (eg for debugging and
  prototyping features)

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SKYPIAX, outbound usage

• Standard interface naming skypiax/interface3
• Eg, from the FS CLI
• bgapi originate skypiax/interface3/Bob 9999
• Will originate a Skype call from interface3 to
  Bob, and connect Bob to extension 9999 of
  dialplan (Music on Hold)
• Round Robin interface naming skypiax/RR
• Eg, from the FS CLI
• bgapi originate skypiax/RR/Bob 9999
• Will originate a Skype call from the first
  available interface (using a RR scheme for
  uniform utilization) to Bob, and connect Bob to
  extension 9999 of dialplan (Music on Hold)

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SKYPIAX, inbound usage

• Each interface will answer inbound calls directed
  to its own configured Skype client (eg to
  Alice or to Bob, as per how the Skype client
  identified itself with the Skype network)
• If you have different interfaces configured with
  different skypenames (eg you have two channels,
  one with Skype client Alice and one with Skype
  client Bob), if the incoming call to Alice find
  the client Alice busy and the client Bob is
  idle, the call will be transferred to Bob.
  Transparently for the caller (caller still thinks
  is Alice to answer).
• If you have multiple instances of client Alice,
  one such idle interface will be automatically
  chosen to answer an incoming call to Alice

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SKYPIAX, HOW to BUILD it

• On Linux and BSD, you need to install the Xvfb
  (fake) Xserver needed by the Skype client and
  the libX11 development package
• Edit the modules.conf in the root of FS sources,
  and uncomment the mod_skypiax line
• Make install
• On Windows, Skypiax is build by default, no need
  for special actions
• Both Linux and Windows You want to download and
  install the 16khz sounds and music (Skypiax is
  16khz native)

11
SKYPIAX Configuration

• Edit the file startskype.sh from
  src/mod/endpoints/mod_skypiax/config to reflect
  the number of Skype clients you want to start and
  which Skype username each one client will use to
  register with the Skype network
• REMEMBER one interface one Skype client
  running. Each interface has its own Skype client
  to remote control
• Copy the configuration file skypiax.conf.xml from
  src/mod/endpoints/mod_skypiax/configs to the
  configuration directory of FreeSWITCH
• Edit the skypiax.conf.xml to reflect how many
  interfaces you will use, specify for each
  interface the same Skype username the configured
  Skype client will register to the Skype network

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SKYPIAX, starting it

• BEFORE TO START FreeSWITCH
• Execute the script startskype.sh (or
  startskype.bat on Windoz)
• Wait until all the Skype clients have been
  started
• Start FreeSWITCH
• Since 1.0.4 it is now possible to add/remove
  Skypiax interfaces on the fly, eg as in starting
  a Skype client instance connected as Bob and
  then add an interface to it to a running
  FreeSWITCH/Skypiax

13
SKYPIAX CLI commands

• Two kinds of commands sk and skypiax gives
  you complete and full control of Skypiax and the
  Skype API
• sk is meant to be used from the command line,
  interactively, to send API command to the Skype
  client remote controlled by a Skypiax interface
• sk is also used to list interfaces' status, and
  to add/remove interfaces on the fly
• skypiax is meant to be used by external
  programs, eg via ESL, to send Skype API command
  to a Skype client remote controlled by a
  particular interface

14
SKYPIAX performances

• Easily 30 concurrent Skype calls per machine
• The load on the server is generated by the Skype
  clients
• On Windows you cannot do anything to lower the
  load generated by Skype clients, but they are
  highly optimized for Windoz, so not big problem
• To minimize the load generated by the Skype
  client instances on Linux (scripts provided for)
• Use the fake Xserver Xvfb
• Use the fake snd-dummy ALSA driver
• To really optimize performances on Linux
• - follow the instructions on wiki for
  custom kernel and custom
  ALSA driver

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Thank you for your attention,
please, any questions?

• for more info http//wiki.freeswitch.org/wiki/Sky
  piax
• Giovanni Maruzzelli
• gmaruzz_at_celliax.org