Contents

Session Description Protocol(SDP)

1. Introduction
2. SDP
3. Multicast SDP Announcements
4. SDP Announcements: Example
5. SDR View of SDP Announcements
6. Conclusions

RFC 2327
1999年12月20日(月)情報工学専攻 修士課程１年
アルミン ラウィ

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1. Introduction

1. Introduction (2)Multicast :• Unicast

IP Multicast :• One-to-Many Communication or
Many-to-Many Communication• Efficient Use of Network Infrastructure:– Single Packet, Multiple Destinations– IP packet replication (routers, when needed!)• Multicast :• Multimedia Application• Broadcast :– QoS and CoS capable networks• ISP Multicast Support
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1. Introduction (4)1. Introduction (3)• Routing protocol for multicasting: DVMRP (DistanceVector Multicast Routing Protocol), PIM (Protocol
Independent Multicast), MOSPF (Multicast OSPF) etc.

• Virtual Network of the Multicast Backbone(Mbone)561

2. SDP2. SDP (2)• Multicast Announcements• SDP is designed to convey session
information to prospective participants• SDP is purely a format for session description- it does not incorporate a transport protocol• Transport protocol: Session Announcement
Protocol (SAP), Session Initiation Protocol(SIP), Real-Time Streaming Protocol (RSTP),
Email using MIME extensions and HTTPSABCD

S-to-D SAP Header text payload
A-to-CSAP Header SAP Header text payload

Ø SAP Header: IP address of Class D;
224.0.0.0 to 239.255.255.255
Ø Text payload: an SDP session description• Email and WWW Announcements
The MIME content type “application/sdp” should be used

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3. Multicast SDP Announcements

2. SDP (3)• Session Description• Information conveyed– Name and purpose of session– Time(s) the session is active– The media comprising the session– Information to receive those media• Some additional information– Information about the bandwidth to be used by
the conference– Contact information for the person responsible
for the session
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3. Multicast SDP Announcements(2)• Time Descriptiont = (time the session is active)r =* (zero or more repeat times)• Media Description
m= (media name and transport address)
i =* (media title)c =* (connection information)b =* (bandwidth information)k =* (encryption key)a =* (zero or more media attribute lines)
Syntax Rules of SDP Announcements and SDP Grammar
given in Appendix A and Appendix B respectively
11v = (protocol version)o = (owner/creator and session identifier)s = (session name)i =* (session information)u =* (URI of description)e =* (email address)
p =* (phone number)c =* (connection information)b =* (bandwidth information)z =* (time zone adjustments)
k =* (encryption key)a =* (zero or more session attribute lines)

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4. SDP Announcements: Example
v=0
o=armin 3154307298 3154307432 IN IP4 133.5.22.66
s=SDP Test in Thunder
i=This is only a test in SDR for using SDP to announcing asession.
u=http://www.csce.kyushu-u.ac.jp/~armin/SDPThunder.txt
e=Armin Lawi <armin@thunder.csce.kyushu-u.ac.jp>
p=Armin Lawi +81-92-6423867
c=IN IP4 239.255.43.180/15
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4. SDP Announcements: Example(2)t=3154305600 3154489200
r=1d 3h 0
a=tool:sdr v2.4a7
a=type:meeting
m=audio 17760 RTP/AVP 0
c=IN IP4 239.255.43.180/15
a=ptime:40
m=video 62978 RTP/AVP 31
c=IN IP4 239.255.152.148/15
m=whiteboard 46510 udp wb
c=IN IP4 239.255.246.30/15
m=text 51400 udp nt
c=IN IP4 239.255.58.76/15

135. SDR View of SDP Announcements

146. Conclusions• The Session Description Protocol (SDP) is an ASCII
text based protocol for describing multimedia sessions
and their related scheduling information.
• The purpose of SDP is to convey information about
media streams in multimedia sessions to allow therecipients of a session description to participate in thesession.
• SDP is primarily intended for use in a internetwork,
although it is sufficiently general that can describe
streams that exist for a duration time.
• Media streams can be many-to-many
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