SIP ISUP interconnection Gonzalo Camarillo Gonzalo Camarilloericsson com

Telephone Services • GSTN (General Switched Telephone Network) • IP Telephony Gonzalo Camarillo Atlanta

Contents • Brief SS 7 introduction (architecture) • Gateway architecture ( SG, MGC, MG

Different architectures GSTN architecture: Intelligence in the network Dumb terminals SIP architecture: Move the

Signalling in GSTN Signalling in the network (between switches) User to network signalling DSS

DSS-1 Q. 931 Protocol between the user and the network Much simpler than ISUP.

Signalling in GSTN SS 7 (System Signalling No. 7) Gonzalo Camarillo Atlanta September 28

General ISUP<->SIP Conversion Voice Stream Signalling SG SIP Server STP ISUP/MTP ISUP/IP SIP MGC

Architecture of the distributed gateway ISUP Signalling Gateway IP side ISUP/IP GSTN side Media

Signalling Gateway Function: • To find the appropriate media gateway controller Signalling GW ISUP/IP

Media Gateway Mapping between different voice formats Control Protocol GSTN Gonzalo Camarillo Atlanta September

Media Gateway Controller for distributed Media Gateways Functions • Actual mapping between protocols (ISUP-SIP)

Experiences implementing ISUP to SIP mapping • Different flavours of ISUP (message flow) •

Different message flows ITU ISUP message exchange during a call ANSI ISUP: CPG before

Overlap signalling (SAMs) European phone numbers does not have a fixed length. Example: +358

Proposed solution Ingress gateway waits for SAMs with more digits a certain amount of

In-band announcements and ring-back tones • ‘Your call is being forwarded to an automatic

ISUP transparency (SIP bridging) Voice Stream SG Signalling SG ISUP/MTP ISUP/IP SIP STP MGC

ISUP transparecy ( SIP bridging) ISUP messages in SIP bodies (MIME), SIP INFO method,

Billing scenarious Isabel calls from Spain to my GSM mobile: +358 40 702 35

Tracing calls • SOS services ( physically closest center ) • Malicious calls An

Further information IETF internet drafts ( www. ietf. org ) • draft-ietf-sigtran-mime-isup-00. txt •

Slides: 22

Download presentation

SIP / ISUP interconnection Gonzalo Camarillo Gonzalo. Camarillo@ericsson. com ASRL Advanced Signalling Research Lab. Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Telephone Services • GSTN (General Switched Telephone Network) • IP Telephony Gonzalo Camarillo Atlanta September 28 th, 1999 GSTN Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Contents • Brief SS 7 introduction (architecture) • Gateway architecture ( SG, MGC, MG ) • ISUP - SIP interworking issues and proposed solutions Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Different architectures GSTN architecture: Intelligence in the network Dumb terminals SIP architecture: Move the intelligence to the edge Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Signalling in GSTN Signalling in the network (between switches) User to network signalling DSS 1 Gonzalo Camarillo Atlanta September 28 th, 1999 ISUP Fall ‘ 99 VON protocols - SIP DSS 1 Advanced Signalling Research Lab.

DSS-1 Q. 931 Protocol between the user and the network Much simpler than ISUP. Q. 921 Handles the transport of the messages Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Signalling in GSTN SS 7 (System Signalling No. 7) Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

General ISUP<->SIP Conversion Voice Stream Signalling SG SIP Server STP ISUP/MTP ISUP/IP SIP MGC IP network SIP MGCP SS 7 SIP Client MG DSS 1 E 1/T 1 Gonzalo Camarillo Atlanta September 28 th, 1999 RTP Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Architecture of the distributed gateway ISUP Signalling Gateway IP side ISUP/IP GSTN side Media Gateway Controller SIP MGCP Voice stream Gonzalo Camarillo Atlanta September 28 th, 1999 Media Gateway Fall ‘ 99 VON protocols - SIP Voice stream Advanced Signalling Research Lab.

Signalling Gateway Function: • To find the appropriate media gateway controller Signalling GW ISUP/IP MGCP Gonzalo Camarillo Atlanta September 28 th, 1999 SIP MGCP ISUP/IP MGC SIP MGCP Fall ‘ 99 VON protocols - SIP MGCP SIP Advanced Signalling Research Lab.

Media Gateway Mapping between different voice formats Control Protocol GSTN Gonzalo Camarillo Atlanta September 28 th, 1999 RTP Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Media Gateway Controller for distributed Media Gateways Functions • Actual mapping between protocols (ISUP-SIP) • Control the Media Gateway/s • Authentication, Authorization and Accounting (AAA) Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Experiences implementing ISUP to SIP mapping • Different flavours of ISUP (message flow) • Overlap signalling (SAMs) • In band announcements and ring-back tone • ISUP transparency • Billing in forwarding situations • Tracing calls (malicious, SOS) Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Different message flows ITU ISUP message exchange during a call ANSI ISUP: CPG before ACM Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Overlap signalling (SAMs) European phone numbers does not have a fixed length. Example: +358 9 299 Finland Helsinki Ericsson 1 Front desk 3371 Camarillo’s The ingress gateway cannot know when the number is complete. Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Proposed solution Ingress gateway waits for SAMs with more digits a certain amount of time. • Timer = 0 Heavy signalling traffic may be generated • Timer = 5 secs ( inter-digit timeout) User is not that patient Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

In-band announcements and ring-back tones • ‘Your call is being forwarded to an automatic voice mail’ • Ring-back tone • Busy tone Proposed solution: 183 SIP response SIP Client MG DSS 1 E 1/T 1 Gonzalo Camarillo Atlanta September 28 th, 1999 RTP Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

ISUP transparency (SIP bridging) Voice Stream SG Signalling SG ISUP/MTP ISUP/IP SIP STP MGC IP network STP MGCP E 1/T 1 RTP MG Gonzalo Camarillo Atlanta September 28 th, 1999 MGC E 1/T 1 MG Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

ISUP transparecy ( SIP bridging) ISUP messages in SIP bodies (MIME), SIP INFO method, reliable 1 xx responses. . . Trusted parties, confidentiality, ISUP flavours. . . Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Billing scenarious Isabel calls from Spain to my GSM mobile: +358 40 702 35 35 (Finland’s international prefix) Isabel pays the call leg Spain-Finland I pay the call leg Finland-Atlanta SIP is end to end … where are the call legs? ? Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Tracing calls • SOS services ( physically closest center ) • Malicious calls An IP address or a SIP URL do not give any useful information for catching the “bad guys”. Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.

Further information IETF internet drafts ( www. ietf. org ) • draft-ietf-sigtran-mime-isup-00. txt • draft-ietf-mmusic-sip-multipart-00. txt • draft-zimmerer-mmusic-sip-isup-mime-00. txt • draft-ietf-mmusic-sip-info-method-01. txt • draft-ietf-mmusic-sip-100 rel-00. txt • draft-roach-mmusic-sip-provisional-media-00. txt • draft-donovan-mmusic-183 -00. txt • draft-roach-mmusic-sip-pstn-require-header-00. txt • draf-zimmerer-mmusic-sip-bcp-t-00. txt • draft-roach-sip-isup-parameters-00. txt • draft-camarillo-mmusic-sip-isup-bcp. txt Gonzalo Camarillo Atlanta September 28 th, 1999 Fall ‘ 99 VON protocols - SIP Advanced Signalling Research Lab.