Transcript (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
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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.
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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.
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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.
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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