Download (IP) Multicast

SIGGRAPH 2002
Topic #3: Continuous Media in Wired and Wireless
Environments
Ronald J. Vetter
Department of Computer Science
University of North Carolina at Wilmington
[email protected]
UNCW
SIGGRAPH 2002
Outline of Presentation
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Protocols for Streaming Continuous Media
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RTP, RTSP, RSVP, SIP, HTTP, IP Multicast
Quality of Network Issues
Mobile and Wireless Networks
- Wireless LANs, MANs and WANs
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Conclusions
References
UNCW
SIGGRAPH 2002
Protocols for Streaming Continuous Media
IP Multicast
RTP
RTSP
HTTP
Continuous
Media
SIP
UNCW
RSVP
SIGGRAPH 2002
Why not use HTTP?
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TCP delivery not always appropriate for
continuous media
– No need for 100% reliability
– Retransmission delay
– Window backoff
– N participants => N*N connections
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HTTP is stateless, media streams persist
HTTP is hard to control (e.g., pause) and lacks
appropriate flow control mechanisms
UNCW
SIGGRAPH 2002
Use a Toolbox Approach
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RTP for transport of audio/video/data with
quality of service feedback
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RTSP for the control of streams
RSVP for reserving resources (when needed)
SIP for inviting participation
HTTP for retrieving media descriptions
IP Multicast for control and data
UNCW
SIGGRAPH 2002
Real-Time Transport Protocol (RTP)
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RTP provides end-to-end network transport
functions suitable for applications transmitting
real-time data, such as audio, video or simulation
data, over multicast or unicast network services.
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RTP does not address resource reservation and
does not guarantee quality-of- service for realtime services.
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The data transport is augmented by a control
protocol (RTCP) to allow monitoring of the data
delivery in a manner scalable to large multicast
networks, and to provide minimal control and
identification functionality.
UNCW
SIGGRAPH 2002
Real Time Streaming Protocol (RTSP)
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RTSP is a client-server application-level protocol
for controlling the delivery of data with real-time
properties.
It establishes and controls either a single or
several time-synchronized streams of continuous
media, such as audio and video.
It uses transport protocols such as UDP, multicast
UDP, TCP, and RTP to deliver the continuous
streams.
RTSP acts as a "network remote control" for
multimedia servers. Sources of data can include
both live data feeds and stored clips.
UNCW
SIGGRAPH 2002
Resource Reservation Protocol (RSVP)
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RSVP is a resource
reservation setup protocol
designed for an integrated
services Internet.
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RSVP provides receiverinitiated setup of resource
reservations for multicast
or unicast data flows, with
good scaling and
robustness properties.
UNCW
SIGGRAPH 2002
Session Initiation Protocol (SIP)
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SIP is an application-layer control (signaling)
protocol for creating, modifying and terminating
sessions with one or more participants.
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These sessions include Internet multimedia
conferences, Internet telephone calls and
multimedia distribution.
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Members in a session can communicate via
multicast or via a mesh of unicast relations, or a
combination of these.
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SIP supports user mobility by proxying and
redirecting requests to the user's current location.
UNCW
SIGGRAPH 2002
Internet Protocol (IP) Multicast
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IP multicast is a bandwidth-conserving
technology that reduces traffic by simultaneously
delivering a stream of information to multiple
recipients.
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Multicast addresses specify an arbitrary group of
IP hosts that have joined the group and want to
receive traffic sent to this group.
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IP multicast group addresses fall in the range of
224.0.0.0 to 239.255.255.255.
UNCW
SIGGRAPH 2002
Basic Operations for Continuous Media
UNCW
SIGGRAPH 2002
References
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RTP - http://www.ietf.org/rfc/rfc1889.txt
RTSP - http://www.ietf.org/rfc/rfc2326.txt
RSVP - http://www.ietf.org/rfc/rfc2205.txt
SIP - http://www.ietf.org/rfc/rfc2543.txt
HTTP - http://www.ietf.org/rfc/rfc2616.txt
IP Multicast - http://www.ietf.org/rfc/rfc1112.txt
Quality of Network – Ferner, C. and Vetter, R. (2002) An Integrated
Framework for Implementing Quality of Network Concepts, Journal of
Network and Systems Management, Vol. 10, No. 4.
UNCW