Home > asterisk, freeswitch, open source, voip > freeswitch knocks asterisk’s block off

freeswitch knocks asterisk’s block off

Freeswitch is gaining popularity among asterisk community these days and looks quite promising, we also migrated our office PBX from asterisk to freeswitch few months back and never faced any issue till now. freeswitch is built from the scratch to address scalability and deadlocks issue within channels,  it’s modular architecture makes it developer friendly.

Freeswitch‘s SIP stack is much better than Asterisk’s sip implementation, Freeswitch uses Sofia sip stack which is 100% RFC compliant(IETF RFC3261 specification). Other than SIP freeswitch supports IAX2, Jingle and Woomera.

Another great thing about freeswitch is that it keeps all its configuration (users/dialplan etc, etc) in XML files. Another more interesting this is unlike asterisk’s dial patterns (e.g. _NXX) freeswitch uses PCRE regular expressions.

Freeswitch comes with an enterprise grade eventing engine, features software based conferences (no hardware timing source required), detailed cdr in XML(btw, i really loved the way freeswitch formats call flow in CDR, specially transfer calls).

Here is a list of Features and possible freeswitch uses:

Possible Uses

  • Rating & Routing Server
  • Transcoding B2BUA
  • IVR & Announcement Server
  • Conference Server
  • Voicemail Server
  • SBC (Session Border Controller)
  • Basic Topology Hiding Session Border Controller
  • Zaptel, Sangoma, Rhino, PIKA Hardware Support (Analog and PRI)


  • Centralized User/Domain Directory (directory.xml)
  • Nano Second CDR granularity
  • Call recording (In Stereo caller/callee left/right)
  • High Performance Multi-Threaded Core engine
  • Configuration via CURL to your http server (xml_curl).
  • XML Config files for easy parsing.
  • Protocol Agnostic
  • Configurable RFC2833 Payload type
  • Inband DTMF generation and detection.
  • Software based Conference (no hardware requirement)
  • Wideband Conferencing
  • Media / No Media modes
  • Proper ENUM/ISN dialing built in
  • Detailed CDR in XML
  • Radius CDR
  • Subscription server
    • Shared Line Appearances
    • Bridged Line Appearances
  • Enterprise/Carrier grade Eventing Engine. (XML Events, Name Value Events, Multicast Events)
  • Loadable File formats and streaming
  • Stream to Shoutcast
  • Multi-lingual Speech Phrase Interface
  • ASR/TTS support (native and via MRCP)
  • Basic IP/PBX features
  • Automated Attendant
  • Custom Ring Back Tones
  • XML RPC support
  • Multiple format CDR’s supported
  • SQL Engine provides session persistence
  • Thread Isolation
  • Parallel Hunting
  • Serial Hunting
  • Mozilla Public License
  • Support
    • Paid support available
    • Free support via IRC & e-mail
  • Many supported codecs
    • G.722 (wideband)
    • G.711
    • G.726 (16k,24k,32k,48k) AAL2 and RFC3551
    • G.723.1 (passthru)
    • G.729 (passthru)
    • AMR (passthru)
    • iLBC
    • speex (narrow and wideband)
    • lpc10
    • DVI4 (ADPCM) 8khz and 16khz
  1. December 5, 2008 at 8:50 am

    And it has extensibility via Mono / Microsoft .NET, so you can use many different languages.

  2. Diego Viola
    December 5, 2008 at 4:30 pm

    The only thing I don’t like about FS is it’s VAD module.

    It’s not very efficient, I hope they will replace it with something that works better soon.

  3. lustyscripps
    December 5, 2008 at 5:56 pm

    FS is indeed great, we’ll eventually have all functionality we need on it, so we can replace all asterisk boxes.

  4. NewbieToPBX
    December 5, 2008 at 7:20 pm

    Native to Windows was what I needed which Asterisk isn’t.

  5. Diego Viola
    December 6, 2008 at 2:32 am

    Why would you ever want to run a VoIP system on Windows anyway?

    Windows sucks.

  6. cyrenity
    December 6, 2008 at 5:17 am

    i know some guys who work for a large commercial bank, a virus caused their CCM on windows went down for a whole working day!

  7. Diego Viola
    December 6, 2008 at 6:13 am

    FreeSWITCH kicks Asterisk ass on every way, but they should really come with a better VAD module.

  8. January 27, 2010 at 8:02 am

    A sign that FreeSWITCH is maturing is that there is now graphical interfaces for it one of the early gui’s was the FreeSWITCH package for the pfSense firewall. That project has now been named FusionPBX and has become multi-platform supporting all the operating systems FreeSWITCH supports. FusionPBX maintains the flexibility and power of FreeSWITCH while adding phone system features and easy management, voicemail to email, fax to email, auto attendants, hunt groups(ring groups) and a lot more.

  1. December 4, 2008 at 4:45 pm
  2. February 2, 2009 at 3:54 pm

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