1. Klara Nahrstedt Spring 2014
CS 414 – Multimedia Systems Design Lecture 23 – Multimedia Session Protocols
Klara Nahrstedt
Spring 2014
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2. Administrative
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3. Outline Multimedia Protocols – Standards
RTP/UDP/IP – Transmission Protocol
RTCP Control/Negotiation Protocol to RTP
RTSP – Control VOD Negotiation Protocol
SIP – Session Initiation Protocol
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4. 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
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5. Session control in layer 5
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6. 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
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7. Session Manager Tasks: Membership control
Monitoring of shared workspace
Coordination of Media control management
Exchange of QoS parameters
Conference control management – establishment, modification, termination
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8. 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
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9. 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
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10. Examples of Session Control protocols: RTSP, SIP, SAP, …
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11. 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
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12. 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
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13. 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
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14. RTSP – Aggregate and Stream Control
DESCRIBE
(aggregate stream)
SETUP
RTSP
RTSP
SID
Decoder
Coder
PLAY
RTP
RTP
ESTABLISH
PLAY
CLIENT
SERVER
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15. Streaming media: meta files
client
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RTSP Presentation by H. Schulzrinne, 2001

16. Streaming Media: RTSP RTSP Presentation by H. Schulzrinne, 2001
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RTSP Presentation by H. Schulzrinne, 2001

17. RTSP Operation RTSP Presentation by H. Schulzrinne, 2001
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RTSP Presentation by H. Schulzrinne, 2001

18. 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
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