An IMS testbed for SIP applications
Cosmin Caba
José Soler {cosm,joss}@fotonik.dtu.dk
Networks Technology and Service Platforms
Agenda
• Problem background + solutions
• IMS service composition and triggering
• SIP Servlet
• Design decisions
• Implementation
• Testing methodology
• Conclusions
2
IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Problem background
• The work has been done as a MSc thesis
project.
• Started during a course in programming
services for NGN.
The students should execute their SIP
applications within a realistic network context.
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Possible solutions for app. testing
• SIPp testing tool (SIP user agent)
– Good UA: custom SIP requests.
– Limited: test single application, no
service composition, no network context.
• Open IMS Core
– Complete implementation of IMS CSCFs.
– Increased complexity, out of scope of the
intented course.
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Proposed solution
• Build a simple emulation for the IMS core entities.
• Requirements:
– Simple to use (collocated with the dev. environment).
– Deploy SIP applications.
– Set up network triggers (i.e. iFC, SPTs).
– Execute SIP applications (composition if
necessary).
Emulate the IMS service composition and
triggering using the SIP Servlet API!
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
IMS service composition
HSS contains the initial Filter
Criteria (iFC) for each subscriber
S-CSCF: service composition
according to the iFC
• Allow for iFC configuration.
• Perform service execution and composition
according to the iFC.
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
SIP Servlet API
• IMS service development.
• Emulation implementation.
Servlet object -> processing of SIP
messages (Route headers).
Application router -> application
selection.
Servlet object + Application router == S-CSCF
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Design decisions
• Applications not tied to a single SIP Servlet Container.
• Handling special cases
(What if the target app. does not exist?).
• Registration possibility.
• Persistent triggers (configuration maintained over server restarts).
• Intuitive user interface.
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Implementation
CSCF:
• Retrieves the iFC set from
the database.
• Creates the service chain.
• Adds the Route headers to
the SIP request.
IMS Application Router:
• Selects the application to be
executed.
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
A short scenario
Server1
IMS AR
IMS Core
Call
(CSCF)
Blocking
Server2
AR
Voice
Mail
INVITE
Route:<sip:callblock@server1;lr>
Route:<sip:cscf@server1;lr>
Route:<sip:voicemail@server2;lr>
Route:<sip:cscf@server1;lr>
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Testing methodology (I)
• Functional testing.
• Inspect messages at the end-points and at the
application server.
Message log from the UA client
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Testing methodology (II)
Message log from the application server
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Conclusions
• Simple yet realistic tesbed for SIP applications.
• Implementation based on the SIP Servlet API.
• Requirements:
– Configure network triggers.
– Perform IMS-like service composition.
• Features:
– Integrated with the development environment.
– Intuitive work flow.
– Easy to set up and run.
• Testing methodology: message log investigation.
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Thank you!
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Backup 1
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Backup 2
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013
Backup 3
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IPTComm 2013
An IMS testbed for SIP applications
15.10.2013