The Open Source PBX

glen b. bastes

Telephony is indispensable in conducting business to be competitive

So Companies spend lot of money to buy their own telephony switch (PABX)

Interesting and new perspectives introduced by VoIP emergence:

Possibility for the deployment enterprise telephony infrastructure using software (software PABX)

Presentation of a PABX• Definition : it is a private telephony switch.• Common Functionalities Direct dialing-in Standard Transfer call Connection to PSTN Automatic recall etc

• Cost between $1300 et $148000

What is a IPBX?• Software which can be installed on a PC or a

server and acting as an auto-switch.Example of software based PABX

• Cisco Call Manager• SipX• OpenSER• Asterisk• And many more.

When: 1999Who : Mark SpencerWhy : “I needed a phone

system and with as small a startup budget as I had for Linux Support Services, I wasn't about to buy one, so building one seemed a logical way to go.”

This guy, right here!

Officially, Asterisk is an Open Source hybrid TDM and packet voice PBX and IVR platform with ACD functionality. Unofficially, Asterisk is quite possibly the most powerful, flexible, and extensible piece of integrated telecommunications software available.

Its name comes from the asterisk symbol, *, which represents a wildcard, matching any filename.

Similarly, Asterisk the PBX is designed to interface any piece of telephony hardware or software with any telephony application, seamlessly and consistently.

• An Open Source Telephony Swiss Army Knife• A Linux Based PBX w/ Minimal Hardware Reqs• A Community Driven Development Project• A Really, Really Disruptive Technology• Asterisk is any call, any time, from anywhere

to anywhere else

Functionalities• Voicemail, conference call, IVR, put in wait of

calls, transfer call, call forwarding, etc. Supported Protocols and codecs

• Protocols : IAX, H.323, SIP, MGCP, Skinny, etc.• Codecs : G711, G723, G726 (ADPCM ), Speek,

GSM, etc.

• Released and developed under GPL, but Digium retains rights to code-base

• All developers submit disclaimers to their code before patches are accepted, allowing for Digium to license specific branches for Commercial projects

• This dual-licensing allows companies to purchase license rights to snapshots of the Asterisk codebase to be used in commercial, non-GPL products

From Wikipedia, the free encyclopedia.Digium is the primary developer and sponsor

of Asterisk™, The Open Source PBX. Digium offers a variety of specially designed low and high density telephony hardware and professional services related to Asterisk. The company is based in Huntsville, Alabama. Digium sells telephony hardware and provides contract services for operating IP based telephony solutions.

• Key System or PBX Replacement• Voicemail Server• Conferencing Server• Call Center ACD Queue• SIP/H323/MGCP Endpoint for IP Phones• Confound and Confuse Telemarketers• Prank Friends with Random Sound Files• Calling Card Application• Predictive Dialer• Home Answering Machine

Suggested architectures• Asterisk server behind PABX Architecture

Suggested architectures Asterisk server in front of the PABX architecture

Suggested architectures• Pure VOIP architecture

Suggested architectures• Interconnexion of multi sites entreprises

Suggested architectures– Interconnexion of multi sites entreprises

These advantages are : - Cost reduction for enterprise telephony

deployment - Easy administration and custom management of the

IPBX - Mobility and remote work- Asterisk facility to integrate information system

(Customer Relationship Management)- Etc.

AvayaSiemensCiscoGrandstreamsnomSipura

RIMPolycomVizufonCounterPath (XTEN)LeadtekFireflyAnd many more…

Internet Paging Terminal• Adding features to an existing VoiceMail system• Establishing and demonstrating reliability• Showing cost savings

Video Conferencing• Demonstrating interoperability• Leveraging existing infrastructure

Voicemail

Internet Paging Terminal

Mail Transfer Agent: sendmail -f paging@abc.com 5161234@xyz.net

PrivateTelephone Network

Internet

TDM

Data Network

X100P TDM400

T100P TE405P

DS3000P S100 IAXY

Linksys PAP-NA2

Cisco 7960 Polycom IP-600

Firefly IAXPhone

Xlite

Voice TeamLAN / WAN TeamServer Team

What is VoIP?• Voice Over IP

– Sending Voice over Internet Protocol• How VoIP works

– Continuously sample analog audio (20 ms)– Convert audio into to a digital signaling

format or codec– Send digitized stream across the Network as

IP packets– Decode the stream to analog for playback

VoIP = Voice Over Internet ProtocolPSTN = Public Switched Telephone Network (AKA

Ma Bell, or The Great Satan)Codec = A Digital Signaling FormatSIP = Session Initiation ProtocolIAX2 = Inter Asterisk Exchange Protocol

• Proxy = Connects Endpoints Together• Registrar = Authenticates Users• Media Gateway = Translates between the PTSN and

Packet Networks• Application Server = Think Webserver• ATA = Analog Telephony Adapter

• The Great Myth– “If I switch to VoIP I’ll get Free Long Distance”– Don’t Believe the Hype

• The Reality– Trade off of Quality and Reliability for Features– Portability / Flexibility– Cost Effectiveness– More Choice and Control– Every Dollar spent on VoIP goes further

• Convergence is happening all around you• There are implementation, management and

maintenance opportunities for consulting companies.

• In 3 years, traditional PBX and Telephone systems will be a thing of the past

• Easy Target - Customers are being saturated w/ VoIP Advertising from the likes of Vonage

• If you don’t provide the service to them, then someone else will

Where To Go For More Information

• Digium Website at http://www.digium.com• Asterisk Website at http://www.asterisk.org• Asterisk Docs Project at http://www.asteriskdocs.org• VoIP Info Wiki at http://www.voip-info.org• Bug Tracker at http://bugs.digium.com• #asterisk on irc.freenode.org