Transcript 04-Xin Chen

Service Control Using SIP in
3GPP’s IP Multimedia
Subsystem (IMS)
Xin Chen
Fujitsu Laboratories of Europe LTD
[email protected]
Contents
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Examples
Part 5. Future work
Part 6. Conclusion
2
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
IMS Overview
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Example
Part 5. Future work
Part 6. Conclusion
3
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
IMS Overview (1) – IMS Architectrure

IMS Architecture
SIP Signaling Interface
Service Control Interface
Diameter Interface
Service Platform
ISC: IMS Service Control
P-CSCF
Out/In Bound
Proxy
ISC
I-CSCF
Entry Proxy Service
Profile
S-CSCF
Service
Proxy
To/From terminating network
IMS User
Visited
Network
4
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Home
Network
IMS Overview (2)-Some important facts
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
IMS is a combination of network and services

IMS provider also owns the service platform

One time registration by Service Proxy

Service Proxy is in the home IMS network

Service control is done in the home IMS network
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
Contents
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Example
Part 5. Future work
Part 6. Conclusion
6
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
IMS Service Architecture (1)-- Requirements
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
Distributed Services Architecture

Support third party applications

Deliver combined, advance services (VoIP, IM, Presence…)

Maximise the network performance

Support service customisation

Support Legacy services (number translation, pre-paid…)
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IMS Service Architecture (2)— Overview
ISC Interface based on SIP
Third Party
Application
Open
Service
Interface
SIP signaling interface
Service control Interface (SIP)
OSA
Gateway
Intelligent Network
SIP
Application
Server
ISC: IMS Service Control
OSA: Open Service Access
IM-SSF: IP Multimedia Service Switch Function
Visited
Network
Home
Network
SIP
Service Proxy
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IM-SSF
IMS Service Architecture (3)—ISC Interface

The roles of ISC interface:




Why SIP






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Service invocation
Present SIP parameters to applications
Interact with Service Proxy for service provisioning
Service invocation is free of basic call model
Service is transparent for the Service Proxy
No additional development needed, purely a SIP proxy
All SIP parameters are presented to applications
Easy to integrate new services (standardised ISC interface)
Maximise the application capabilities (user agent, proxy server, B2BUA)
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
Contents
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Example
Part 5. Future work
Part 6. Conclusion
10
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
IMS Service Control (1)—Service Invocation and Interaction



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
Service triggers on initial SIP requests at Service Proxy
Service Proxy proxies request to corresponding AS based on triggers
AS acts as user agents, proxy server, 3PCC or B2BUA
AS may Record-Route SIP request to stay in signalling path
Service Proxy maintains the states between dialogs sent to/from
applications
AS
SIP Request
SIP Initial Req
SIP Initial Request
SIP Request
Triggered!
Service Proxy
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IMS Service Control (2)—Service Triggers


SIP methods (e.g. REGISTER, INVITE, SUBSCRIBE, MESSAGE);
presence or absence of any header;
content of any header;
direction of the request
session description information (SDP).

Initial Filter criteria (iFC) (described using XML)
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
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Service Point Triggers (SPTs) are those points in the SIP
signalling on which Filter Criteria can be set.
address of the Application Server to be contacted;
Trigger Point: combination of SPTs by means of logical expressions (AND,
OR,NOT, etc.);
priority of the iFC (in case SPTs trigger multiple iFCs);
Default handling (either reject or proxy the request);
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
Contents
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Example
Part 5. Future work
Part 6. Conclusion
13
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
Service Example (1) —Single Application Server case
Example 1: Single application server triggering
Presence
Server
Initial Filter Criteria of Presence Server
4.200 OK
3. PUBLISH
Application Server Address: presence.operator.com
Trigger point:
Event=“presence” AND Method = PUBLISH AND
Request-URI= “sip:[email protected]”
Handling: Proxy
2. Filter Evaluation
Priority: x
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1. PUBLISH
5. 200 OK
Service Proxy
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Sip: [email protected]
Service Examples (2) —Multiple Application Server case
Example 2: Multiple application servers triggering
Initial Filter Criteria of Prepaid Server
Messaging
Server
Prepaid
Server
Application Server Address:
prepaid.operator.com
Method = MESSAGE OR INVITE AND From=
“sip:[email protected]”
Handling: Proxy
Priority: 1
3. MESSAGE
4. MESSAGE
Trigger point:
Initial Filter Criteria of Messaging Server
8. MESSAGE
1. MESSAGE
Sip: [email protected]
5. Filter Evaluation
Service Proxy
Application Server Address:
message.operator.com
Trigger point:
Method = MESSAGE
Handling: Proxy
Priority: 2
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Service Example (3)—Service Interactions
Example 3: Service interactions
Initial Filter Criteria of Presence Server
Messaging
Server
Presence
Server
Application Server Address:
presence.operator.com
Priority: x
9. NOTIFY
10. MESSAGE
Handling: Proxy
5. SUBSCRIBE
Event=“presence” AND Method = SUBSCRIBE
AND Request-URI=“sip:[email protected]”
4. MESSAGE
Trigger point:
3. MESSAGE
1. PUBLISH
11. MESSAGE
Service Proxy
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Contents
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Example
Part 5. Future work
Part 6. Conclusion
17
© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
Future Work

Dynamic trigger points assignment (Subsequent Filter Criteria)
AS1
SIP Initial Req
SIP Message
with sFC (New header or in
body?)
sFC installed!
SIP Initial Request
Triggered!
SIP Message
Service Proxy
Further study service interactions in multiple application
server environment.
 Evaluate other alternatives for IMS service control (etc.
SOAP)

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© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved
Contents
Part 1. IMS Overview
Part 2. IMS Service Architecture
Part 3. IMS Service Control
Part 4. Service Example
Part 5. Future work
Part 6. Conclusion
19
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Conclusion– Do we meet the requirements?
Standardised ISC interface!
 Distributed Services Architecture Done!
Open service interface!
 Support third party applications
Done!
Using SIP for service control!
 Deliver combined, advance services Done!
Application
server
is
supper
box!
 Maximise the network performance
Done!
Static and dynamic service filtering! Done!
 Support service customisation

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SIPLegacy
to BSCM
mapping! Done!
Support
services
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Thank you!
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© Copyright Fujitsu Laboratories of Europe Limited. All rights reserved