Application sharing Henning Schulzrinne Jonathan Lennox Jason Nieh

Application sharing Henning Schulzrinne Jonathan Lennox Jason Nieh Ricardo Baratto Columbia University IETF 61 (November 2004) MMUSIC 1

Overview • No good way to share application state in a conference – T. 120 does not integrate well with SIP – proprietary solutions – treat as video source does not deal well with windows, user input • Goal: integrate into IETF session architecture • Assumption: treat remote access (“vnc”, “terminal server”) and sharing as same problem IETF 61 (November 2004) MMUSIC 2

Components • • Session setup User input (HMI) Screen output to remote users Moderating access to input focus (devices) IETF 61 (November 2004) MMUSIC 3

Basic requirements • • • F 1: application sharing & remote desktop F 2: desktops (screens) + windows F 3: any number of users F 4: cannot modify applications F 5: protocol negotiation F 6: modular architecture IETF 61 (November 2004) MMUSIC 4

Input • I 1: may not have actual device • I 2: private, authenticated, … • I 3: at most one simultaneous user typical, but not always • I 4: hints (e. g. , modal input) • I 5: indicate focus • I 6: relative timing needed (e. g. , video games) • I 7: I 18 N • I 8: Copy-and-paste? IETF 61 (November 2004) MMUSIC 5

Video output • V 1: different resolutions, color depth • V 2: both lossy (e. g. , embedded video, CGA) and lossless data • V 3: window layering hints • V 4: semi-transparent windows • V 5: relative timing information • V 6: absolute timing information • V 7: variety of encodings • V 8: no assumption of common fonts IETF 61 (November 2004) MMUSIC 6

Audio and full-motion video • A 1: share audio streams, sync’ed to video • A 2: share full-motion window as part of shared application • A 3: receiver may choose not to receive high-bandwidth components (e. g. , motion video window during presentation) IETF 61 (November 2004) MMUSIC 7

Transport • • • T 1: some parts require perfect reliability T 2: large number of receivers T 3: heterogeneous bandwidth T 4: minimize latency T 5: work well in low- and high-latency environments IETF 61 (November 2004) MMUSIC 8

What’s next? • Is this a problem for MMUSIC or AVT? • Basic architecture assumption – sound? – SIP (or similar) for session setup – SDP(ng) for parameter negotiation – transport: RTP as one option? – keyboard and mouse input • RTP as well? • part of signaling? (KPML etc) • Need to define new payload formats IETF 61 (November 2004) MMUSIC 9