Qsig Encapsulation Over SIP Encapsulation Over SIP Qsig audet@ - - PowerPoint PPT Presentation

Qsig Qsig Encapsulation Over SIP Encapsulation Over SIP

audet audet@ @nortelnetworks nortelnetworks.com .com long@ long@nortelnetworks nortelnetworks.com .com mzonoun@ mzonoun@nortelnetworks nortelnetworks.com .com

What is Qsig?

• Qsig is a family of standards providing connectivity between

corporate network switches, Centrex switches as well as corporate network to Centrex switches.

• Qsig specifies a set of supplementary services, the service specific

"Qsig" signalling protocols for the exchange of information between switches across an interface at the "Q" reference point.

• Qsig basic call is a symmetrical (peer-to-peer) version of ISDN

DSS1.

• QSIG generic procedures provide support for the supplementary
• services. These procedures allow for standardized and proprietary

supplementary services to coexist.

What is needed?

• Transport of QSIG signaling between call servers as part of the

payload of SIP messages.

• Support of in-band tones and announcement
• Transport of mid-call information in both directions

— Qsig messages that do not map easily to SIP messages — Qsig supplementary service information — Notifications

• All these requirements are similar to ISUP

IP

PSTN PSTN

SIP CS SIP CS

PBX PBX Qsig encapsulated

Architecture

What extensions are required for PBX signaling?

• A “best current practices” for private network PBX signaling with

QSIG as an alternative to ISUP

— Mapping between QSIG and SIP

• A SIP/QSIG MIME type
• SIP INFO method
• SIP 183 Session progress message

INVITE sip:14084955072@sc1.nortelnetworks.com SIP/2.0 From: sip:14085655675@sc10.nortelnetworks.com To: sip:14084955072@sc1.nortelnetworks.com Call-ID: 1231999021712095500999@sc12.nortelnetworks.com Content-Length: .. Content-Type: multipart/mixed; boundary=unique-boundary-1 MIME-Version: 1.0

• -unique-boundary-1

Content-Type: application/SDP; charset=ISO-10646 v=0

• =audet 2890844526 2890842807 5 IN IP4 134.177.64.4

s=SDP seminar c=IN IP4 MG141.nortelnetworks.com t= 2873397496 2873404696 m=audio 9092 RTP/AVP 0 3 4

• -unique-boundary-1

Content-type:application/QSIG;version=ISO Content-Transfer-Encoding: binary 08 02 55 55 05 04 02 90 90 18 03 a1 83 01 70 0a 89 31 34 30 38 34 39 35 35 30 37 32

Illustrative example

Supporting Slides

Call setup with locally generated tones

PSTN 2 Call server 1 Call server 2 PSTN 1 SETUP INVITE (SETUP) SETUP CALL PROC 100 TRYING CALL PROC ALERTING 180 RINGING (ALERTING) ALERTING

Locally generated ringback

CONNECT 200 OK (CONNECT) CONNECT Two-way voice path ACK

Call setup with far-end generated tones

PSTN 2 Call server 1 Call server 2 PSTN 1 SETUP INVITE (SETUP) SETUP CALL PROC 100 TRYING CALL PROC 183 SESSION PROG

(CALL PROC)

PROGRESS CONNECT 200 OK (CONNECT) CONNECT On-way voice path Two-way voice path

In-band ringing Progress indicator = in-band tones Progress indicator = in-band tones

ACK

Call tear-down

PSTN 2 Call server 1 Call server 2 PSTN 1 DISCONNECT BYE (DISCONNECT) RELEASE 200 OK RELEASE COMP DISCONNECT RELEASE RELEASE COMP

User busy with locally generated tones

PSTN 2 Call server 1 Call server 2 PSTN 1 SETUP INVITE (SETUP) SETUP 100 TRYING RELEASE COMP 600 BUSY everywhere

(RELEASE COMP)

Cause = user busy Locally generated ringback (cause = busy)

CALL PROC DISCONNECT RELEASE RELEASE COMP

User busy with far-end generated tones

PSTN 2 Call server 1 Call server 2 PSTN 1 SETUP INVITE (SETUP) SETUP CALL PROC 100 TRYING CALL PROC 183 SESSION PROG

(CALL PROC)

PROGRESS On-way voice path

In-band busy tone Progress indicator = in-band tones

DISCONNECT BYE (DISCONNECT) RELEASE 200 OK RELEASE COMP DISCONNECT RELEASE RELEASE COMP

Progress indicator = in-band tones User hangs up

Transfer of mid-call messages

PSTN 2 Call server 1 Call server 2 PSTN 1 NOTIFY INFO (NOTIFY) NOTIFY 200 OK INFO (INFORMATION) INFORMATION 200 OK INFORMATION INFO (FACILITY) FACILITY 200 OK FACILITY