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BUNDLE

BUNDLE. Christer Holmberg, Ericsson Harald Alvestrand , Google IETF#84, Vancouver. ICE PEER-REFLEXIVE CANDIDATES. USE-CASE. Alice supports BUNDLE Bob does not support BUNDLE Alice and Bob support ICE Alice sends offer with identical address:port information for each m- line

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BUNDLE

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  1. BUNDLE Christer Holmberg, Ericsson Harald Alvestrand, Google IETF#84, Vancouver

  2. ICEPEER-REFLEXIVE CANDIDATES

  3. USE-CASE • Alice supports BUNDLE • Bob doesnotsupport BUNDLE • Alice and Bob support ICE • Alice sendsoffer with identicaladdress:portinformation for each m- line • Bob sendsanswer with differentaddress:portinformation for each m- line • Alice and Bob exchange ICE candidateinformation

  4. USE-CASE OFFER: m=audio p1 candidates m=video p1 candidates ALICE (BUNDLE) BOB p2 AUDIO AUDIO VIDEO p1 p3 ANSWER: m=audio p2 candidates m=video p3 candidates VIDEO NOTE: SDP does not contain peer-reflexive candidates.

  5. PROBLEM • Bob sends STUN Connectivity Check (SCC) request to Alice • Sourceaddress:port of SCC is unknown to Alice • Creates PEER-REFLEXIVE CANDIDATE • Alice doesnotknowfromwhich m- line SCC is sent • SCC doesnotcontain component id, basecandidate, etc. • Not a problemifboth Alice and Bob support BUNDLE • SCC willbesent for whole BUNDLE group

  6. SOLUTION • Alice offers separate ufrag values for each m- line • SCC contains ufrag • Alice can map SCC to correct m- line

  7. SOLUTION OFFER: m=audio p1 candidates a=ufrag:xxx m=video p1 candidates a=ufrag:yyy ALICE (BUNDLE) BOB p2 AUDIO AUDIO VIDEO p1 p3 VIDEO SCC ufrag:yyy

  8. USE-CASE with RTCP-MUX • Alice includes a=rtcp-mux attribute • Alice includes a=rtcp attribute, with RTP port value • Bob does not support rtcp-mux • Creates separate ports for RTP and RTCP • Assume that Bob supports a=rtcp attribute, and can send RTP and RTCP to same port

  9. PROBLEM with RTCP-MUX • Bob sends STUN Connectivity Check (SCC) request to Alice • Sourceaddress:port of SCC is unknown to Alice • Creates PEER-REFLEXIVE CANDIDATE • Alice doesnotknowwhether SCC is sent for RTP or RTCP • SCC doesnotcontain component id, basecandidate, etc. • Not a problemifboth Alice and Bob supportrtcp-mux

  10. SOLUTION with RTCP-MUX • ALT 1: • Usedifferentufragvalues for RTP and RTCP • Connectivity checkrequestcontainsufrag • Q1: How to provideseparateufragvalues? • Q2:Allowed, for a given m- line, to includetwoa=ufragattributeinstances? • Q2a:Even if, how to indicatewhich is for RTP and which is for RTCP?

  11. SOLUTION with RTCP-MUX • ALT 2: • Use different ports for RTP and RTCP • Unless both Alice and Bob support rtcp-mux • Alice can still use same RTP port, and same RTCP port, for all m- lines associated with the BUNDLE group • Separate ufrag per m- line

  12. SOLUTION with RTCP-MUX (Alt 2) ALICE (BUNDLE) BOB RTP AUDIO RTCP RTP AUDIO VIDEO RTCP RTP VIDEO RTCP

  13. SDP RESTRICTIONS

  14. INTRODUCTION • BUNDLE follows general RFC 3264 rules for SDP offer/answer • Somerestrictionsdue to usage of identical IP address:port for multiple m- lines • Transport related • RTP session related (single vsmultiple RTP sessions) • RTP session relatedrestrctions outside the scope of thispresentation

  15. IDENTICAL INFORMATION • The following information must be identical in every m- line associated with a BUNDLE group. • Information sharing, or describing, properties of the 5-tuple transport connection • ICE candidate IP address:port • Transport encryption information

  16. NON-IDENTICAL INFORMATION • The following information does not need to be identical in every m- line associated with a BUNDLE group. • Media description specific information • Codec/payload type properties • Direction attributes • ICE ufrag • Bandwidth (more about bandwidth on next slide)

  17. BANDWIDTH • Bandwidthparametersare set as in a non-BUNDLE case • Total bandwidth for a BUNDLE group: • Sum of all media descriptionspecificbandwidthvalues of the BUNDLE group • b=AS

  18. THANK YOU FOR LISTENING!

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