building complex voice over ip (voip) applications based on open-source
DESCRIPTION
The paper summarizes and proofs that existing VoIP programs are powerful and flexible enough to build complex applications. The applications are independent and can be used either stand-alone or within carrier-grade Telco environments. The described example of building a call center application (outbound calling) shows the power that lies not only in existing open-source Session Initiation Protocol (SIP) servers, but also in simple SIP tools. The costs for implementing those systems are at a very low level, as the functions each project performs are rather kept simple, but the combination possibilities are tremendously flexibility. The presented application has been deployed successfully within NGNlab (http://www.ngnlab.eu) as a Proof of Concept (PoC). Presented at Elmar 2009 in Zadar, Croatia.TRANSCRIPT
MotivationWork and Results
Summary
Building Complex Voice Over IP (VoIP)Applications Based on Open-Source
Sebastian Schumann Ondrej Lábaj Pavol Podhradský
Department of TelecommunicationsFaculty of Electrical Engineering and Information Technology
Slovak University of Technology, Bratislava
51. International Symposium ELMAR 2009,28.-30. September, Zadar, Croatia
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
Outline
1 MotivationPrerequisitsDefinition
2 Work and ResultsSystemUtilization
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
PrerequisitsDefinition
Open-Source Software in Telecommunications
Open-source world offers many applicationsin the area of Voice over IP (VoIP)Wide range of developed software
ToolsApplicationsCarrier-grade software
Not too many complex systems at the moment
IdeaCombine open-source software and environmentsto perform large tasks in a flexible way.
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
PrerequisitsDefinition
Task
AimFulfill typical tasks of a call-center:The target application should call a list of usersand send successfull calls to a media system/agents.
Application components should be independentCost-effective IP based solutionsSimple task flow:
Input List of usersSystem Attempt calls, route successful attemptsOutput Provide statistics, clean terminations
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Input
List of users to call (CSV)Destination(s) (cron)Max. timeout/retransmissions of initial INVITE (cron)Time period for calling users
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Component Interaction
timer
.csv
user data
GeneratorAnalyzer
cron
Media
media stream
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Tools
Call Generator: SIPpSIPp is a free Open Source test tool / trafficgenerator for the SIP protocol.
Call Evaluation System: OpenSIPSOpenSIPS (Open SIP Server) is a mature OpenSource implementation of a SIP server.
Media System AsteriskAsterisk is the world’s leading open source PBX.
Execution environment for all applications is GNU/Linux.
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Logical Actions
LOG Release call
LOG
LOG
Call user
Yes
Media
End condition onmedia system*
NoCall established
user sideCall released on Interruption
Connect to media system
* Timer ends, SIPp receives BYE...
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Call Flow (Establishment)
User
200 OK+SDP1
PBXSIPpOpenSIPS
INVITEINVITE
INVITE+SDP1
200 OK+SDP2
ACK
off-hook200 OK+SDP1
ACK+SDP2ACK+SDP2
RTP
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Call Flow (User hangs up)
User PBXSIPpOpenSIPSBYE BYE
200 OK200 OK BYE
200 OK
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Call Flow (System closes call)
User PBXSIPpOpenSIPSBYE
200 OKBYE
200 OK200 OK
BYE
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
SystemUtilization
Examples
Automatic calling of users with voice advertisingprovided by media server.Certain call center agents (i.e., SIP users) will beconnected to successful call establishments.(maximum amount of parallel calls monitored on SIPp,maximum utilization of call center)
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
1 MotivationPrerequisitsDefinition
2 Work and ResultsSystemUtilization
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
Summary
Existing VoIP applications are very powerfulCarrier-grade IP based Telco environments can beeasily extendedUsage of presented work (e.g., within ad campaigns) isvery cost effective
OutlookContinue with useful call-center use cases(e.g., extend OpenSIPS with call queuing functionality)Elaborate other use cases where IP based telephonysystems or applications can enhance functionality
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications
MotivationWork and Results
Summary
Contact
Sebastian SchumannDepartment of TelecommunicationsSlovak University of TechnologyBratislava, Slovak Republic
Schumann, Lábaj, Podhradský Complex Open-Source Based VoIP Applications