4 March 2004draft-burger-xcon-models-001 Centralized Conferencing Media Control Models Eric W m. Burger 59 th IETF Seoul, ROK

4 March 2004draft-burger-xcon-models-002 Media Manipulation Models Low-Level Device Control –Manipulate Media Resource Objects –Manipulate Plumbing Between Objects Application-Level Device Control –Manipulate Conference Primitives –Conference, Sidebar, Speaker, Preferred Speaker Dynamic Device Control –Manipulate Semantic Primitives –Mixer Advertises and Endpoint Learns Capabilities

4 March 2004draft-burger-xcon-models-003 Low-Level Device Control Characteristics Client Specifies Plumbing Client Specifies Low-Level Media Processing –Internal Media Topology –Algorithm Graph –Connections to Media Resources

4 March 2004draft-burger-xcon-models-004 Example: Conference With Three Loudest Talkers in Mix Create Input Multiplexer Create Selector that Detects Three Loudest Talkers Create Mixer that Mixes All Streams Create 3 Subtraction Resources Create Output Multiplexer Connect Inputs to Selector Connect Inputs to Mixer Connect Outputs of Mixer to Subtraction Resources Connect Outputs of Selector to Subtraction Resources Connect Outputs of Selector to Output Multiplexer

4 March 2004draft-burger-xcon-models-005 Examples Play Prompt Into Conference Create Audio Player Connect Audio Player –Into Mixer, if Mixed In –Disconnect Multiplexer, Connect to Endpoints if Played Out Start Audio Player Record Conference Create Audio Recorder Connect Audio Recorder to Output of Mixer Start Audio Recorder

4 March 2004draft-burger-xcon-models-006 Implementations of Low-Level Device Control H.248 –Follows Steps Outlined On Previous Slides –Create Graph as Sequence of Commands draft-even-sipping-media-policy- requirements-00 and draft-mahy-xcon-media-policy-control-01 –Assert Graph in XML –Assert Changes to Graph Using, e.g., XPATH

4 March 2004draft-burger-xcon-models-007 Pro/Con of Low-Level Pro Absolutely No Limit to Topology Absolutely No Limit to Mixing Algorithm Con “Anything Can Be Done in Assembly Language” Applications Must be Constructed in Terms of DSP Resources, not Application Constructs –Wrong Programmer Market Media Processor Cannot Optimize Resources –Three-Loudest Talkers is Often Single DSP Image, not 7 Resources –Three-Loudest With Preference is Often Single DSP Image, not 9 Resources DSP Resources is the Level of Control

4 March 2004draft-burger-xcon-models-008 Application-Level Device Control Characteristics Client Specifies Conference-Level Requests –Create a Conference –Join Users to Conference –Mute a Leg –Set Preferred Speaker –Select Mixing Algorithm –Play Prompt –Record Conference

4 March 2004draft-burger-xcon-models-009 Examples Conference With Three Loudest Talkers In Mix –Create Conference (INVITE) –INVITE Attendees to Conference Mute Leg –Tell Mixer to Mute Leg Use Preferential Mixing –Tell Mixer that Leg is in Preferred Mix Play Prompt –Tell Conference to Play Prompt Record Conference –Tell Conference to Record Conference Perform IVR on Leg –Tell Conference to Detach Leg –Play/Collect –Tell Conference to Put Back Leg

4 March 2004draft-burger-xcon-models-0010 Implementations of Application- Level Device Control draft-vandyke-mscml-04 –SIP Invented for Conferencing –SIP Appropriate for Loosely-Coupled Development Model –Use Loose Coupling

4 March 2004draft-burger-xcon-models-0011 Pro/Con of Application-Level Pro Application-Level Construction –Programmer Productivity –LOC/day –What it Takes to do Same Task Model is Conference (Application)-level, Not DSP Level Conference Is the Resource Controlled Con Algorithms and Topologies Fixed Not Clear if This is Bug or Feature

4 March 2004draft-burger-xcon-models-0012 Dynamic Device Control Client Discovers Capabilities of Media Processor Media Processor Presents Set of Templates Templates are Application-Appropriate Templates are Self-Describing –Dynamic, On-the-Fly Control Construction

4 March 2004draft-burger-xcon-models-0013 Examples Conference With Three Loudest Talkers In Mix –Ask for Basic Conference Template –INVITE Attendees to Conference –Fill-In Template With Attendees Mute Leg –Fill-In Template to Mute Leg Use Preferential Mixing –Fill-In Template to Say Leg is in Preferred Mix Play Prompt –Create/Connect to Player –Fill-In Template to Direct Stream to Player –Start Player –Fill-In Template to Put Stream Back

4 March 2004draft-burger-xcon-models-0014 Pro/Con of Dynamic Pro Application-Level Construction –Programmer Productivity –LOC/day –What it Takes to do Same Task Model is Conference (Application)-level, Not DSP Level Con Mixer, not Conference, Is the Resource Controlled Model Not Directly Amenable to Conference IVR Needs Is This a Problem?