SIP in 3GPP August 12th, 2000 Adam Roach [email protected]

SIP in 3GPP

August 12th, 2000

Adam Roach

[email protected]

Disclaimer

Some terms used in this presentation are trademarks or registered trademarks of their respective owners. The use of these terms is not an endorsement of the related product or corporation; the terms are included only to give the audience concrete example with which they are (hopefully) already familiar.

3GPP Network Model

GfGi

Iu

GiMr

Gi

Ms

Gi

R UuMGW

Gn

Gc

TE MT UTRAN

Gr

SGSN GGSN

EIR

MGCF

R-SGW *)

MRF

MultimediaIP Networks

PSTN/Legacy/External

Applications &Services *)

Mm

Mw

Legacymobile

Network

Mc

Cx

AlternativeAccessNetwork

Mh

CSCF

CSCF

Mg

T-SGW *)

T-SGW *)

HSS *)

HSS *)

Applications& Services *)

MSC server GMSC server

McMc

D C

SCP

CAP

MGWNb

Nc

Iu

Iu

R-SGW *)Mh

CAPCAP

IP Multimedia Domain(multimedia by SIP,IETF RFC2543)

CS Domain(multimedia by ITU H.324M)

PS Domain

CSCF

Different Kinds of CSCFs

P-SCSFP-SCSFVisited B

S-CSCFS-CSCF

Home A

1

2

7

10

11 12

13

15

17

P-CSCFP-CSCFVisited A

18

AB

GGSNGGSNSGSNSGSN

Radio Access NetworkRadio Access Network

GGSNGGSNSGSNSGSN


S-CSCFS-CSCF

Home B

8

I-CSCFI-CSCF

HSSHSS

9

14

6

34

I-CSCFI-CSCF

HSSHSS

5

16

Proxy CSCF:Provides emergency service breakout, triggers for locally-provided services, and number normalizing (per local dialing plan)



S-CSCFS-CSCF

Home A

1

2

7

10

11 12

13

15

17


18

AB

GGSNGGSNSGSNSGSN


GGSNGGSNSGSNSGSN


S-CSCFS-CSCF

Home B

8

I-CSCFI-CSCF

HSSHSS

9

14

6

34

I-CSCFI-CSCF

HSSHSS

5

16

Interrogating CSCF:Queries the HSS to find the correct S-CSCF. First point of contact for incoming call signalling.



S-CSCFS-CSCF

Home A

1

2

7

10

11 12

13

15

17


18

AB

GGSNGGSNSGSNSGSN


GGSNGGSNSGSNSGSN


S-CSCFS-CSCF

Home B

8

I-CSCFI-CSCF

HSSHSS

9

14

6

34

I-CSCFI-CSCF

HSSHSS

5

16

Serving CSCF:Provides subscriber services.

3GPP SIP Decisions

• SIP from terminal to network• SIP between network call nodes

General Principles

• S-CSCFs may have different capabilities.

• Firewalling must be possible.

• Terminal and node behaviours should be consistent, regardless of whether the user is roaming.

• Follow IETF standards as much as possible.

• Service nodes are access independent.

• Serving CSCFs may reside in either home or roamed-to network.

(Ideal) Access Independent Network

PSTN

PSTN GW owned by traditional telco. Calling users subscribe; authorization/billing based on challenge/response model

GGSN

SGSNCMTS

Broadband Access Providers (Wireless, Cable, DSL, etc.)

Pay-per-view movie service using RTSP, hosted by backbone provider Service

Node

Worldcom

Service Node

Yahoo!

Service Node

My own machine with a multicast chat server for all my friends, connected through my broadband access

IP IP

IPIP

Peer IP backbone networks

Service Node

Short Term Network Picture

IP

PSTN

Call Control

PSTN

PSTN

PSTN

IP

IP

IPFirewallFirewall

FirewallFirewall

Call Control

Call Control

Call Control

IP Backbone

Access

Access

Access

Access

LocationLocation

I-CSCFI-CSCF

Home

P-CSCFP-CSCFVisited

GGSNGGSNSGSNSGSN


S-CSCFS-CSCF

HSS

ProfileProfile

Selection of ServingNode Location(Home Execution)

2. REGISTER 9. OK

1. REGISTER 10. OK

3 4

5. REGISTER

8. OK

6 7

LocationLocation

I-CSCFI-CSCF

Home

P-CSCFP-CSCF

GGSNGGSNSGSNSGSN


S-CSCFS-CSCF

HSS

ProfileProfile

Selection of ServingNode Location(Non-Roaming)

2. REGISTER 9. OK

1. REGISTER 10. OK

3 4

5. REGISTER

8. OK

6 7

LocationLocation

I-CSCFI-CSCF

Home

P-CSCFP-CSCF

Visited

GGSNGGSNSGSNSGSN


S-CSCFS-CSCF

HSS

ProfileProfile

I-CSCFI-CSCF

LocationLocation ProfileProfile

HSS

Selectionof Serving

NodeLocation(Visited

Execution)2. REGISTER 13. OK

1. REGISTER14. OK

3 4

8. REGISTER

11. OK

9 10

5. REGISTER

12. OK

6 7

S-CSCFS-CSCF I-CSCFI-CSCF

HSSHSS

P-CSCFP-CSCF

Visited

I-CSCFI-CSCFMGCF/T-SGWMGCF/T-SGW

MGWMGW

HSSHSS

GGSNGGSNSGSNSGSN


PSTN

Visited-DomainProvided Service(e.g. 411 DirectoryAssitance) 4

5. INVITE

14. 200

1. INVITE tel:1411

2. INVITE sip:info@visited

15. 200

16. 200

6. INVITE 13. 200

9. INVITE

12. 200

7 8

10. IAM

11. ANM

3

Updates URI

Non-Conversational Services

GGSNGGSNSGSNSGSN


WebServerWeb

ServerIP

BackboneMediaServerMediaServer

Future Issues to be Decided

• Handling of Instant Messages (SMS). SIP “MESSAGE” seems a natural fit, but other ideas are being proposed

• Uses of MRF (Media Resource Function) node. Possible uses include:– Conference Bridge (both dial-in and spontaneous)– Transcoding– Streaming Media/Announcments

Wireless Services Implications

IP backbone

Access

Called

Access

CallerValue added

servicesValue added

services

Home

API

(S-CSCF)

SIP

Bearer Services oriented

WireLine

WireLine


WLanWLan

Home

API

(S-CSCF)

SIP


WireLine

WireLine

TA?

WLanWLan

FW?

TA?GPRSGPRS

Value addedservices

Value addedservices

UTRANUTRANFW?

TA?UTRANUTRANGPRSGPRS

Video/Audio/Signaling Video/Audio/Signaling

signaling signaling

Conclusions

• 3G is dedicated to using SIP for call control.• This development will allow a seamless

integration of “smart” wireless terminals into the exploding information/communication IP networks.

• If deployed correctly, the transition to 3G networks will be a revolution in wireless communications unlike any previously seen.

Documents

SIP in 3GPP August 12th, 2000 Adam Roach [email protected]