Klara Nahrstedt Spring 2014 CS 414 – Multimedia Systems Design Lecture 23 – Multimedia Session Protocols Klara Nahrstedt Spring 2014 CS 414 - Spring 2014

Administrative CS 414 - Spring 2014

Outline Multimedia Protocols – Standards RTP/UDP/IP – Transmission Protocol RTCP Control/Negotiation Protocol to RTP RTSP – Control VOD Negotiation Protocol SIP – Session Initiation Protocol CS 414 - Spring 2014

Internet Multimedia Protocol Stack Media encaps (H.264, MPEG-4) DASH APPLICATION SIP RTSP RSVP RTCP Layer 5 (Session) HTTP RTP Layer 4 (Transport) TCP DCCP UDP KERNEL Layer 3 (Network) IP Version 4, IP Version 6 AAL3/4 AAL5 MPLS Layer 2 (Link/MAC) Ethernet/WiFi ATM/Fiber Optics CS 414 - Spring 2014

Session control in layer 5 CS 414 - Spring 2014

Session Management (Layer 5) Control of multiple multimedia connections Separates control aspects from transport aspects SESSION MANAGER Conference control Participant Management Session Control Protocol (e.g., RTSP) Session Control Media control Configuration control Presentation data communication whiteboard Continuous data communication video Continuous data communication audio CS 414 - Spring 2014

Session Manager Tasks: Membership control Monitoring of shared workspace Coordination of Media control management Exchange of QoS parameters Conference control management – establishment, modification, termination CS 414 - Spring 2014

Session Control Session Described by Session state Name of session, start, valid policies Session management – two steps for state processing Establishment of session Modification of session CS 414 - Spring 2014

Session Control Conference Control Media Control Configuration Control Centralized or distributed approach Media Control Synchronization Configuration Control Negotiation of QoS parameters, admission control and reservation/allocation of resources Membership Control Invitation of users; registration of users, change of membership CS 414 - Spring 2014

Examples of Session Control protocols: RTSP, SIP, SAP, … CS 414 - Spring 2014

Real-Time Streaming Protocol (RTSP) Application Protocol for Control of multimedia streams This is not an application data transmission protocol, just remote control protocol between client and server Audio Video Decoder AudiovideoCoder Session Control RTSP RTSP RTP RTP CLIENT SERVER CS 414 - Spring 2014

RTSP Approved as Internet Draft, February 2, 1998, authors H. Schulzrinne, A. Rao, R. Lanphier Enables controlled, on-demand delivery of real-time data such as audio and video Intends to control multiple data delivery sessions Provides means for choosing delivery channels UDP Multicast UDP, TCP CS 414 - Spring 2014

RTSP Methods Request Direction Description OPTIONS S <-> C Determine capabilities of server (S) or client (C) DESCRIBE C -> S Get description of media stream ANNOUNCE Announce new session description SETUP C -> S Create media session RECORD Start media recording PLAY Start media delivery PAUSE Pause media delivery REDIRECT S -> C Use other server TEARDOWN Destroy media session SET_PARAMETER Set server or client parameter GET_PARAMETER Read server or client parameter CS 414 - Spring 2014

RTSP – Aggregate and Stream Control DESCRIBE (aggregate stream) SETUP RTSP RTSP SID Decoder Coder PLAY RTP RTP ESTABLISH PLAY CLIENT SERVER CS 414 - Spring 2014

Streaming media: meta files client CS 414 - Spring 2014 RTSP Presentation by H. Schulzrinne, 2001

Streaming Media: RTSP RTSP Presentation by H. Schulzrinne, 2001 CS 414 - Spring 2014 RTSP Presentation by H. Schulzrinne, 2001

RTSP Operation RTSP Presentation by H. Schulzrinne, 2001 CS 414 - Spring 2014 RTSP Presentation by H. Schulzrinne, 2001

Conclusion Internet protocol suite has now basic ingredients to support streaming audio and video Both for distribution and communication applications Challenges: No session control protocol that can be used to perform floor control in distributed multimedia conferences Network reliability and deployment multicast of services with predictable quality-of-service are major hurdles beyond need for continuous upgrades in network capacity CS 414 - Spring 2014