A General overview of Asterisk Framework ( an Open Source, Private Branch eXchange (PBX) and telephony toolkit)

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WTH is Asterisk !!
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2. Asterisk Server
Internet
Softphone/ Hard phone Softphone/ Hard phone
1.1 Basic Call Routing
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3. VOIP
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Definition
1. Voice Over Internet Protocol
2. group of technologies for the delivery of voice communications and multimedia
sessions over Internet Protocol network.
Why Use It ?
1. Cost Effective
2. Functionality
How does it Work ?
1.2 VoIP Routing
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IP Phone Ethernet Router Internet Router Ethernet IP Phone
Server Server

4. SIP
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Definition
1. Session Initiation Protocol
2. signaling Protocol for IP communication.
1. initiating, maintaining, modifying and terminating real-time sessions.
3. SIP itself does not provide communication services.
Sends IP Package
IP Communication
Laptop(IP device 1) Phone(IP device 2)
IP network
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IP Communication
1. Location (IP Address)
2. Same Codec (For Encoding-Decoding)
SIP
Locate
other
party
How to
construc
t & Send
Packets
How to
Manage
Sessions
Which
Codec
1.3 SIP
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SDP
Definition
1. Session description Protocol
2. When SIP packets are send and received the both parties need to know
the media details(transport address, transport address, transport
protocol, codec, ports and other session description metadata).
3. SDP is used to advertise such information.
1.4 A SIP Packet
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Asterisk
1. It is a complete PBX(Private Branch exchange) in software.
2. Can Run on Windows, Linux, OS X.
3. How to install Asterisk ?
What Can we do with Asterisk ?
1. Call Conferencing
2. intercom calling extension to extension
3. Interactive Voice Response(IVR)
4. Call Queuing etc.
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1.5 A Basic Call Flow (Outgoing)
User Mobile Phone
Asterisk ServerIP phone Cellular Tower
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Converts 3G,4G,GSM to SIP
Calling
Asterisk ServerIP phone IPTSP
SIP Trunk
SynesisIT
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1.6 Basic Call Flow (Extended)

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Asterisk Codebase
❑ File :
1. Path : etc/asterisk
2. Path : var/lib/asterisk
Sip.conf exention.conf
Audio Script
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1.7 sip Trunk setup in sip.conf
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SIP TRUNK

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1.7 extention.conf(Code Demo)
[robi_airtel_360]
exten => _X.,1,Answer()
exten => _X.,2,SayDigits(123)
exten => _X.,3,,SayNumber(123)
exten => _X.,n,Hangup
[robi_airtel_360]
exten => _203,1,Hangup
[robi_airtel_360]
exten => _X.,1,Answer()
exten => _X.,n,Background(welcome&silence/3)
exten => _X.,n,Background(testsounds/allServiceAbout)
exten => 1,1,Playback(welcomeToService)
exten => 1,2,AGI(robi-pg/pg_registration.php,GYN,START)
exten => 2,1,Playback(welcomeToServiceSecond)
exten => 2,2,AGI(robi-pg/pg_registration.php,BAN,START)
exten => _[*#03456789],n,Hangup
exten => h,1,AGI(mkvas/mk_cdr_update.php)
Context
Extension , priority ,
application
Dial plan
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1. IVR
2. Cli
3. Channel Variable

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[airtel_pg-ivr-free-min]
exten => un,1,Set(trycount=0)
exten => un,2,Background(pg_sounds/pg_sub_free_zero)
exten => un,n,Background(silence/3)
exten => un,n,Background(pg_sounds/pg_sub_free_zero)
exten => un,n,Background(silence/3)
exten => un,n,Background(pg_sounds/pg_no_number)
exten => un,n,Background(pg_sounds/pg_sub_free_zero)
exten => un,n,Background(silence/3)
exten => un,n,Background(pg_sounds/pg_max_no_number)
exten => un,n,Hangup
exten => 0,1,Goto(airtel_pg-unsubscribed,un,1)
exten => 1,1,AGI(robi-pg/pg_recharge.php)
;exten => 1,n,Playback(pg_sounds/pg_request_accepted)
exten => 1,n,GotoIf($["${is_recharged}" = "SUCCESS"]?pg-ivr-incoming,in,4)
exten => 1,n,Background(pg_sounds/pg_sub_recharge_failed)
;exten => 2,1,Goto(airtel_pg-gyan-branches-unsub,bn,1)
exten => _[23456789],1,Playback(pg_sounds/pg_wrong_number)
exten => _[23456789],n,Set(trycount=$[${trycount}+1])
exten => _[23456789],n,GotoIf($["${trycount}" != "3"]?airtel_airtel_,un,2)
exten => _[23456789],n,Playback(pg_sounds/pg_max_try)
exten => _[23456789],n,Hangup
exten => h,1,AGI(robi-pg/pg_cdr_update.php)
1.8 More extention.conf(Code Demo)
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References
❑ SIP : https://tools.ietf.org/html/rfc3261#section-8.2.2.3
❑ Mobile VoIP: https://www.voip-info.org/wiki/view/Mobile+VoIP
❑ Asterisk: https://www.voip-info.org/wiki/view/Asterisk
❑ PBX: https://www.voip-info.org/wiki/view/PBX
❑ extentions.conf: http://www.asteriskguru.com/tutorials/extensions_conf.html
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❑ Icons: https://www.flaticon.com

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Thank You