--- 1/draft-ietf-mmusic-sdp-cs-15.txt 2013-01-09 10:14:59.519708449 +0100 +++ 2/draft-ietf-mmusic-sdp-cs-16.txt 2013-01-09 10:14:59.579707620 +0100 @@ -1,21 +1,21 @@ MMUSIC WG M. Garcia-Martin Internet-Draft Ericsson Intended status: Standards Track S. Veikkolainen -Expires: June 20, 2013 Nokia - December 17, 2012 +Expires: July 13, 2013 Nokia + January 9, 2013 Session Description Protocol (SDP) Extension For Setting Up Audio and Video Media Streams Over Circuit-Switched Bearers In The Public Switched Telephone Network (PSTN) - draft-ietf-mmusic-sdp-cs-15 + draft-ietf-mmusic-sdp-cs-16 Abstract This memo describes use cases, requirements, and protocol extensions for using the Session Description Protocol (SDP) Offer/Answer model for establishing audio and video media streams over circuit-switched bearers in the Public Switched Telephone Network (PSTN). Status of this Memo @@ -25,25 +25,25 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on June 20, 2013. + This Internet-Draft will expire on July 13, 2013. Copyright Notice - Copyright (c) 2012 IETF Trust and the persons identified as the + Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -540,22 +540,22 @@ o The Calling Party Number information element in the circuit- switched signaling might not be available, e.g., due to policy restrictions of the network operator or caller restriction due to privacy. o The Calling Party Number information element in the circuit- switched signaling might be available, but the digit representation of the E.164 number might differ from the one expressed in the SDP. To mitigate this problem implementations should consider only some of the rightmost digits from the E.164 - number for correlation. For example, the numbers +44-113-469-0123 - and 0113-469-0123 could be considered as the same number. This is + number for correlation. For example, the numbers +44-113-496-0123 + and 0113-496-0123 could be considered as the same number. This is also the behavior of some cellular phones, which correlate the incoming calling party with a number stored in the phone book, for the purpose of displaying the caller's name. 5.2.3.3. User-User Information Element Correlation Mechanism A second correlation mechanism is based on including in SDP a string that represents the User-User Information Element that is part of the call setup signaling of the circuit-switched bearer. The User-User Information Element is specified in ITU-T Q.931 [ITU.Q931.1998] and @@ -1291,24 +1291,24 @@ endpoint when establishing the PSTN call, and he also includes the "a=cs-correlation" attribute line containing the values he is going to include in the Calling Party Number and User-User IE of the PSTN call establishment. v=0 o=- 2890973824 2890987289 IN IP4 192.0.2.7 s= t=0 0 m=audio 9 PSTN - - c=PSTN E164 +441134690124 + c=PSTN E164 +441134960124 a=setup:active a=connection:new - a=cs-correlation:callerid:+441134690124 \ + a=cs-correlation:callerid:+441134960124 \ uuie:56A390F3D2B7310023 Figure 5: SDP Answer with circuit-switched media When Alice receives the Answer, she examines that Bob is willing to become the active endpoint when setting up the PSTN call. Alice temporarily stores Bob's E.164 number and the User-User IE value of the "cs-correlation" attribute, and waits for a circuit-switched bearer establishment. @@ -1370,33 +1370,32 @@ Upon receiving the SDP offer described in Figure 7, Bob rejects the video stream as his device does not currently support video, but accepts the circuit-switched audio stream. As Alice indicated that she is able to become either the active, or passive party, Bob gets to select which role he would like to take. Since the Offer contained the international E.164 number of Alice, Bob decides that he becomes the active party in setting up the circuit-switched bearer. Bob includes a new value in the "dtmf" subfield of the "cs- correlation" attribute, which he is going to send as DTMF tones once - the bearer setup is complete. For the video bearer, caller ID based - correlation is used. The Answer is described in Figure 8 + the bearer setup is complete. The Answer is described in Figure 8 v=0 o=- 2890973824 2890987289 IN IP4 192.0.2.7 s= t=0 0 a=setup:active a=connection:new - c=PSTN E164 +441134690124 + c=PSTN E164 +441134960124 m=audio 9 PSTN - a=cs-correlation:dtmf:654321 m=video 0 PSTN 34 - a=cs-correlation:dtmf:+441134690124 + a=cs-correlation:callerid:+441134960124 Figure 8: SDP answer with circuit-switched audio and video (2) 7. Security Considerations This document provides an extension on top of RFC 4566 [RFC4566], and RFC 3264 [RFC3264]. As such, the security considerations of those documents apply. This memo provides mechanisms to agree on a correlation identifier or @@ -1523,23 +1522,24 @@ Type SDP Name Reference -------------- --------------------------- --------- proto PSTN [RFCxxxx] The related "fmt" namespace re-uses the conventions and payload type number defined for RTP/AVP. In this document, the RTP audio and video media types, when applied to PSTN circuit-switched bearers, represent merely an audio or video codec in its native format directly on top of a single PSTN bearer. - In come cases, the endpoint is not able to determine the lsit of + In come cases, the endpoint is not able to determine the list of available codecs for circuit-switched media streams. In this case, in order to be syntactically compliant with SDP [RFC4566], the + endpoint MUST include a single dash ("-") in the subfield. 9. Acknowledgments The authors want to thank Paul Kyzivat, Flemming Andreasen, Thomas Belling, John Elwell, Jari Mutikainen, Miikka Poikselka, Jonathan Rosenberg, Ingemar Johansson, Christer Holmberg, Alf Heidermark, Tom Taylor, Thomas Belling, Keith Drage, and Andrew Allen for providing their insight and comments on this document. 10. References