1 / 6

Offer/Answer & Multipart Alternative

Offer/Answer & Multipart Alternative. Cullen Jennings <fluffy@cisco.com> & Medhavi Bhatia John Oliver {mbhatia, joliver}@nextone.com. Documents. draft-jennings-sipping-certs-04 Cullen Jennings Jon Peterson draft-bhatia-mmusic-sdp-altcap-01.txt Medhavi Bhatia John Oliver

scot
Download Presentation

Offer/Answer & Multipart Alternative

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Offer/Answer & Multipart Alternative Cullen Jennings <fluffy@cisco.com> & Medhavi Bhatia John Oliver {mbhatia, joliver}@nextone.com

  2. Documents • draft-jennings-sipping-certs-04 • Cullen Jennings • Jon Peterson • draft-bhatia-mmusic-sdp-altcap-01.txt • Medhavi Bhatia • John Oliver • {mbhatia, joliver}@nextone.com

  3. Problem • Example that started it: • Alice offers two SDP bodies, one for RTP, one for SRTP. How does Bob indicate which offer was selected? • Side note: Can not try SRTP then try RTP. If voicemail does SRTP, will never get a RTP UA. • General problem: • If Alice sends a multipart/alternative, how does Bob indicate which alternative was used.

  4. Solution • Inclusion of Content-ID in each multipart entity. • Definition of a new MIME header: • Content-Reference • Allows answerer to indicate which MIME body in the offer is being responded to.

  5. Example Offer Content-Type: multipart/alternative; boundary=’xxx’ --xxx Content-Type: application/sdp Content-ID: <o100@spock.example.com> v=0 o=- 25678 753849 IN IP4 128.96.41.1 s= c=IN IP4 128.96.41.1 t=0 0 m=audio 3456 RTP/AVP 0 m=video 3458 RTP/AVP 31 --xxx Content-Type: application/sdp Content-ID: <o101@spock.example.com> v=0 o=- 25678 753849 IN IP4 128.96.41.1 s= c=IN IP4 128.96.41.1 t=0 0 m=audio 3456 RTP/AVP 18 m=video 3458 RTP/AVP 34 --xxx-- Answer Content-Type: application/sdp Content-Reference: <o100@spock.example.com> v=0 o=- 25678 753849 IN IP4 128.96.41.1 s= c=IN IP4 128.96.41.1 t=0 0 m=audio 49000 RTP/AVP 0 m=video 59000 RTP/AVP 31

  6. Require Header • SIP Require header needed? • Can implicitly deal with this by saying if a UAS supports multipart/alternative, then it needs to add the header. • Recommendation: Make it explicit and add an option tag.

More Related