Multipath RTP (MPRTP)

IETF 90, Toronto

Transcript

1. Multipath RTP Varun Singh, Teemu Karkkainen, Jörg Ott, Saba Ahsan, Lars Eggert IETF 90, Toronto 23 July 2014 draft-singh-avtcore-mprtp-09
2. Since IETF 83 (Paris) •  Split document into RTP-related and SDP- related –  avtcore-mprtp –  mmusic-mprtp-sdp-extension •  Requested by MMUSIC (IETF83) •  Updates based on feedback from implementers –  Frederick Maze, Canon –  Ralf Globisch, Fraunhoffer HHI –  Tiru Reddy, Cisco Thank you!
3. Reminder (1/2) •  Splitting an RTP session across multiple paths for load balancing and/or robustness •  Seemed to be a ok idea. (IETF 78…83) A B …
4. Reminder (2/2) •  RTP header extension – Subflow ID – Subflow sequence numbers •  Subflow RTCP for reporting path characteristics •  Advertise Multipath Candidates – in RTCP (currently in the draft), or – In SDP, or – draft-wing-mmusic-ice-mobility (mice)
5. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |V=2|P|1| CC |M| PT | sequence number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | timestamp | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | synchronization source (SSRC) identifier | +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | 0xBE | 0xDE | length=2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ID | LEN=4 | 0x0 | LEN=4 | Subflow ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subflow-specific Seq Number | Pad (0) | Pad (0) | +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ | RTP payload | | .... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MPRTP Header Extensions
6. Multipath RTCP (MPRTCP) •  RTP and RTCP multiplexed •  Regular RTCP SR/RR sent as compound packets •  MPRTCP Subflow reports sent as non- compound (reduced size RTCP)
7. Subflow RTCP http://tools.ietf.org/html/draft-singh-avtcore-mprtp 7
8. Does MPRTP compare well to RTP? calculated over 10 runs 8 MPRTP:  multipath  considerations  for  real-­‐time  media   http://www.netlab.tkk.fi/~jo/papers/2013-mmsys-mprtp.pdf
9. Paths with different RTT Bit rate Ratio per path time in sec 0 0.2 0.4 0.6 0.8 1 0 50 100 150 200 250 optimum_end_to_end_delay = 150ms N ms 2xN ms 3xN ms Use path for ARQ, I-frames Increasing traffic distribution 9
10. WLAN + 3G Ratio time (s) 0 0.2 0.4 0.6 0.8 1 0 20 40 60 80 100 120 140 160 180 200 220 240 260 bitrate (kbps) Path A (3G) Link Capacity 0 250 500 750 1000 bitrate (kbps) Path B (WLAN) 0 250 500 750 1000 PSNR: MPRTP (lossy): 46.72 ± 0.21 (Single path): 48.427 10
11. mmusic-mprtp-sdp-extension •  MPRTP interface advertisements in SDP – Without ICE – With ICE •  MPRTP for RTSP
12. Next Steps •  Is there interest in WG to pursue? •  There are new pieces that MPRTP could use: – Trickle ICE – ICE Mobility – Multiplexing …