Transcript 10-NEW-pavitra_sip_04 - Computer Science, Columbia University

SIP Extensions for Enhanced Location Based
Services in 3G Networks
International SIP 2004, Paris
Pavitra Krishnaswamy
[email protected]
Application-Ready Platform Solutions™
AGENDA

SIP in 3G Networks – An Introduction

Location Based Services

Role of SIP in Location Based Services

Proposed Solutions

Sample Call Flows

Q&A
2
SIP in 3G Networks – An Introduction

SIP chosen to be protocol of choice for signaling in
3G release 5 IP Multimedia subsystem.

Motivation




Need for a Converged Network
Simplicity of the protocol
Extensibility
Support for Mobility in SIP
3
3G UMTS Release 5 Architecture
UTRAN
PS-CN
RNC
SGSN
GGSN
Towards
Destination
Network
IMS
Towards
Destination
network
UMTS : Universal Mobile Telecom System
UTRAN : UMTS Terrestrial Radio Access
Network
RNC : Radio Network Controller
PS-CN : Packet Switched Core Network
IMS : IP Multimedia Subsystem
SGSN : Serving GPRS Support Node
GGSN : Gateway GPRS Support Node
Signaling
User Data
4
IP Multimedia Subsystem (IMS)
Signaling
SIP
I-CSCF
P-CSCF
SIP
IMS
User Data
S-CSCF
SIP
MG
CSCF : Call State Control Function
P-CSCF : Proxy CSCF
I-CSCF : Interrogating CSCF
S-CSCF : Server CSCF
MG
: Media Gateway
MGC
: Media Gateway Controller
HSS
: Home Subscriber Server
MGC
User Data to/from Destination
Network
5
HSS
Location Based Services

Location Based Services can be described as
"applications, which re-act according to a geographic
trigger".
A Geographic trigger might be the
input of a Town name, Zip code or
Street into a web page, the position of
a mobile phone user or the precise
position of your car as you are driving
home from the office.
6
Location Based Services (LBS)

Need For LBS



Commercial Uses:
e.g.: Location based entertainment information.
Network Uses
e.g.: Network service related procedures
Emergency Uses
e.g.: 911 calls
7
Traditional Location Services Model
 To support Location based services the 3G Network
provides a method to discover the location of a UE. This
procedure is termed as Location Services (LCS).
 Two types of location services are possible:
- Network Initiated : Initiated by SGSN
- Client Initiated : Initiated by external client node or by the
originating mobile device(UE)
8
Traditional Location Services Model
The following steps are involved in Location Services:
A remote client or a requests the SGSN for location information.
SGSN requests the radio network (UTRAN) to locate the mobile
device.
UTRAN provides location coordinates after communicating with
the device.
SGSN provides the co-ordinates to the requested nodes/ clients
9
Traditional Location Services Model
Network Initiated Location Services
SGSN
Radio Network
Mobile Device
Location Request
UE positioning messages
Location Report
Traditional Location Services Model
UE Initiated Location Services
HLR/HSS
SGSN
Radio Network
Mobile Device
Service Request
Security Procedures
Service Invoke
Location Request
UE positioning messages
Location Report
Service Response
Traditional Location Services – An Example
Wireless Network
RNC
5
SGSN
7
6. Locate Mobile
1. Request Nearest
Spanish Restaurant
Location
2. Forward Request to
Application Server
Global/Local
Database
Application
Server
12. Restaurant
Information
4. Request Location
of
the mobile
13.Restaurant
Information
8. Location of
mobile
3. Request
Location of
mobile
9. Location of
the mobile
Location Server
SIP & Location Based Services

For multimedia calls and calls that require location
based services SIP can be used to carry the location
co-ordinates of the mobile device(UE) to the
application server.

UE’s can request special location based service by
inserting a specific SIP header into the message.
13
SIP & Location Based Services

Why use SIP for LBS?


SIP message headers can be easily extended to carry
location information and to request location based
services.
By inserting the location data for multimedia calls
when initiating call signaling, additional location
services procedures need not be initiated by application
servers on receiving the request thus saving time &
network bandwidth.
14
Proposed Solutions – Solution 1
Two solutions have been proposed to use SIP to enhance
location based services(LBS) in a 3G network.
Solution 1:
- The mobile device initiates the LCS procedures to
discover its geographical co-ordinates, for calls requiring
LBS.
- The LCS procedures used will be that prescribed in the
normal 3G procedures.
- The Mobile device inserts location information into SIP
signaling on completion of LCS procedures.
15
Solution 1 : A Conceptual View
Multimedia/ LBS Calls
Destination
S-CSCF
Network Serving Proxy
P-CSCF
(Visiting
Network
Proxy)
GGSN
SGSN
Radio Network
Mobile
Service Request
Service Invoke
Location Request
UE positioning messages
Location Report
Service Response
SIP Signaling with embedded location information
SIP
SIP
Location Based Services based on Solution 1–
An Example
Global/Local
Database
Wireless Network
RNC
3. Locate Mobile
1. Request Mobile
Location
2
7. Forward Request to
Application Server
Location : Bercy, France
SGSN
10. Restaurant
Information
4
5. Mobile Location
Response
Location : Bercy, France
11. Restaurant Information
6. Request Nearest
Spanish Restaurant
Location :
Location : Bercy,
France
Application
Server
Proposed Solutions – Solution 1

Pros :



The Mobile Device is responsible for providing the location
information .
The network is not required to implement additional procedures or
use additional resources to determine UE location.
Cons:


The handset/ UE will need to be enhanced to initiate LCS
procedures for specific calls.
The mobile device needs to be made more intelligent to change call
initiation procedures based on the type of call.
18
Proposed Solutions- Solution 2
Solution 2 :

The Proxy (P-CSCF) in the visited network performs the LCS
procedures.

The P-CSCF, in this case, will request the SGSN to locate the user
coordinates for calls that require location based services.

P-CSCF will insert location information into SIP Signaling on
completion of LCS procedures.

All procedures described above are only done for calls requiring
Location Based Services.
19
Solution 2 : A Conceptual View
Multimedia Calls / Calls Requiring Location Based Services
Destination
S-CSCF
Network Serving Proxy
P-CSCF
Visiting
Network
Proxy
GGSN
SGSN
Radio Network
Mobile
SIP signaling including header(s) requesting Location Based Service
Location Request
Location Request
UE positioning messages
Location Report
Location Report
SIP signaling including location information
Location Based Services based on Solution 2–
An Example
Global/Local
Database
7. Forward Request to
Application Server
Wireless Network
3
SGSN
RNC
5
4. Locate Mobile
6. Mobile
Location:
Location : Bercy, France
10. Restaurant
Information
2. Locate Mobile
Bercy, France
1. Request Nearest
Spanish Restaurant
P-CSCF
11. Restaurant Information
Application
Server
Proposed Solutions – Solution 2

Pros :
- Time and network bandwidth Savings :


Implementing LCS at the initiating end can help avoid separate
procedures to do the same at the destination network.
Cons:
- The Proxy CSCF will need to be enhanced to communicate with the
SGSN, to initiate LCS procedures.
- Complicated P-CSCF (proxy) Implementation.
 The P-CSCF will need additional intelligence to insert the location
information into the SIP signaling.
 The proxy-CSCF might now require a B2BUA implementation of
the SIP stack instead of a regular SIP proxy.
22
Extensions to SIP for use in 3G LCS
Based on the earlier proposals, the following extensions
are required in the SIP protocol to support location
services:
1) New parameter in Request URI


The new parameter ,”user = lcs” will be added to the
Request URI field in the SIP header.
The parameter will inform the network entities that a call
requires location based services.
23
Extensions to SIP for use in 3G LCS
2 ) New SIP header



The new header, ‘location :’, will carry location coordinates
and wireless cell information.
This header will be filled by the proxy (P-CSCF) or the UE
when it wants to send location information inside the SIP
message.
The new SIP header concept may have security implications.
Alternatively, the location data could be inserted into the
SIP body, to avoid this issue.
24
Summary

SIP selected as protocol of choice for 3G IM
subsystems.

SIP can be enhanced easily to improve Location
based services in 3G Networks.

Two solutions proposed to use SIP for Location
Based Services.

New Headers required in SIP for use in LCS
procedures.
25
Continuous Computing Mission
To be the leading provider of
high availability, Application-Ready
Platform solutions for telecom equipment
manufacturers and carriers
Voice-overPacket
Intelligent
Networks
26
2.5G & 3G
Wireless
Continuous Computing Solutions
Systems
Protocols
- FLEX21 cPCI PICMG 2.16
- FLEX ATCA
Modules
- Single Blade CPU
-Control Node
- I/O Module
- Ethernet Switch
- Trillium stacks
Continuous
Computing
HA SW
- Trillium DFT/HA
- FlexManager
- upSuite
App-Ready
Platforms
Services
- Integration, customization,
application development,…
- Home Location Register
- Serving GPRS Support Node
- Signaling GW
27
Contact
Continuous Computing
9380 Carroll Park Drive
San Diego, CA 92121
Tel: (858) 882 8800
[email protected]
www.ccpu.com
Pioneering Application-Ready Platforms™
28