An IMS testbed for SIP applications Cosmin Caba José Soler {cosm,joss}@fotonik.dtu.dk Networks Technology and Service Platforms.

An IMS testbed for SIP applications

Cosmin CabaJosé Soler {cosm,joss}@fotonik.dtu.dk

Networks Technology and Service Platforms

15.10.2013An IMS testbed for SIP applications2 IPTComm 2013

Agenda

• Problem background + solutions

• IMS service composition and triggering

• SIP Servlet

• Design decisions

• Implementation

• Testing methodology

• Conclusions

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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.

The students should execute their SIP applications within a realistic network context.

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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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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!

Emulate the IMS service composition and triggering using the SIP Servlet API!

15.10.2013An IMS testbed for SIP applications6 IPTComm 2013

S-CSCF: service composition according to the iFC

HSS contains the initial Filter Criteria (iFC) for each subscriber

• Allow for iFC configuration.

• Perform service execution and composition according to the iFC.

• Allow for iFC configuration.

• Perform service execution and composition according to the iFC.

IMS service composition

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SIP Servlet API

• IMS service development.

• Emulation implementation.

Servlet object + Application router == S-CSCFServlet object + Application router == S-CSCF

Servlet object -> processing of SIP messages (Route headers).

Application router -> application selection.

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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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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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A short scenario

IMS Core

(CSCF)

Call

Blocking

Voice

Mail

Server1 Server2

Route:<sip:callblock@server1;lr>

Route:<sip:cscf@server1;lr>

Route:<sip:voicemail@server2;lr>

Route:<sip:cscf@server1;lr>

INVITE

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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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Testing methodology (II)

Message log from the application server

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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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Thank you!

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Backup 1

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Backup 2

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Backup 3