draft-ietf-mmusic-offer-answer-examples-02.txt   draft-ietf-mmusic-offer-answer-examples-03.txt 
MMUSIC Working Group A. Johnston MMUSIC Working Group A. Johnston
Internet-Draft MCI Internet-Draft MCI
Expires: August 15, 2004 R. Sparks Expires: December 29, 2004 R. Sparks
dynamicsoft dynamicsoft
February 15, 2004 June 30, 2004
Session Description Protocol Offer Answer Examples Session Description Protocol Offer Answer Examples
draft-ietf-mmusic-offer-answer-examples-02 draft-ietf-mmusic-offer-answer-examples-03
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and any of which I become aware will be disclosed, in accordance with
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Abstract Abstract
This document gives examples of Session Description Protocol (SDP) This document gives examples of Session Description Protocol (SDP)
offer answer exchanges. Examples include codec negotiation and offer answer exchanges. Examples include codec negotiation and
selection, hold and resume, and addition and deletion of media selection, hold and resume, and addition and deletion of media
streams. The examples show multiple media types, bidirectional, streams. The examples show multiple media types, bidirectional,
unidirectional, inactive streams and dynamic payload types. Common unidirectional, inactive streams and dynamic payload types. Common
Third Party Call Control (3pcc) examples are also given. Third Party Call Control (3pcc) examples are also given.
Table of Contents Table of Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Codec Negotiation and Selection . . . . . . . . . . . . . . . 3 2. Codec Negotiation and Selection . . . . . . . . . . . . . . . 3
2.1 Audio and Video 1 . . . . . . . . . . . . . . . . . . . . . . 3 2.1 Audio and Video 1 . . . . . . . . . . . . . . . . . . . . 3
2.2 Audio and Video 2 . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Audio and Video 2 . . . . . . . . . . . . . . . . . . . . 4
2.3 Audio and Video 3 . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Audio and Video 3 . . . . . . . . . . . . . . . . . . . . 6
2.4 Two Audio Steams . . . . . . . . . . . . . . . . . . . . . . . 6 2.4 Two Audio Streams . . . . . . . . . . . . . . . . . . . . 6
2.5 Audio and Video 4 . . . . . . . . . . . . . . . . . . . . . . 7 2.5 Audio and Video 4 . . . . . . . . . . . . . . . . . . . . 7
2.6 Audio Only 1 . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.6 Audio Only 1 . . . . . . . . . . . . . . . . . . . . . . . 8
2.7 Audio and Video 5 . . . . . . . . . . . . . . . . . . . . . . 9 2.7 Audio and Video 5 . . . . . . . . . . . . . . . . . . . . 9
2.8 Audio and Video 6 . . . . . . . . . . . . . . . . . . . . . . 11 2.8 Audio and Video 6 . . . . . . . . . . . . . . . . . . . . 11
3. Hold and Resume Scenarios . . . . . . . . . . . . . . . . . . 11 3. Hold and Resume Scenarios . . . . . . . . . . . . . . . . . . 11
3.1 Hold and Unhold 1 . . . . . . . . . . . . . . . . . . . . . . 11 3.1 Hold and Unhold 1 . . . . . . . . . . . . . . . . . . . . 11
3.2 Hold with Two Streams . . . . . . . . . . . . . . . . . . . . 13 3.2 Hold with Two Streams . . . . . . . . . . . . . . . . . . 13
4. Addition and Deletion of Media Streams . . . . . . . . . . . . 14 4. Addition and Deletion of Media Streams . . . . . . . . . . . . 14
4.1 Second Audio Stream Added . . . . . . . . . . . . . . . . . . 14 4.1 Second Audio Stream Added . . . . . . . . . . . . . . . . 14
4.2 Audio then Video Added . . . . . . . . . . . . . . . . . . . . 15 4.2 Audio then Video Added . . . . . . . . . . . . . . . . . . 15
4.3 Audio and Video, then Video Deleted . . . . . . . . . . . . . 16 4.3 Audio and Video, then Video Deleted . . . . . . . . . . . 16
5. Third Party Call Control (3pcc) . . . . . . . . . . . . . . . 18 5. Third Party Call Control (3pcc) . . . . . . . . . . . . . . . 18
5.1 No Media, then Audio Added . . . . . . . . . . . . . . . . . . 18 5.1 No Media, then Audio Added . . . . . . . . . . . . . . . . 18
5.2 Hold and Unhold 2 . . . . . . . . . . . . . . . . . . . . . . 19 5.2 Hold and Unhold 2 . . . . . . . . . . . . . . . . . . . . 19
5.3 Hold and Unhold 3 . . . . . . . . . . . . . . . . . . . . . . 20 5.3 Hold and Unhold 3 . . . . . . . . . . . . . . . . . . . . 20
6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 6. Security Considerations . . . . . . . . . . . . . . . . . . . 21
7. Changes since -00 . . . . . . . . . . . . . . . . . . . . . . 21 7. Changes since -00 . . . . . . . . . . . . . . . . . . . . . . 21
8. Changes since -01 . . . . . . . . . . . . . . . . . . . . . . 21 8. Changes since -01 . . . . . . . . . . . . . . . . . . . . . . 21
Informative References . . . . . . . . . . . . . . . . . . . . 21 9. Changes since -02 . . . . . . . . . . . . . . . . . . . . . . 21
10. Informative References . . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 22
Intellectual Property and Copyright Statements . . . . . . . . 23 Intellectual Property and Copyright Statements . . . . . . . . 23
1. Overview 1. Overview
This document describes offer answer examples of Session Description This document describes offer answer examples of Session Description
Protocol (SDP) based on RFC 3264 [1]. The SDP in these examples are Protocol (SDP) based on RFC 3264 [1]. The SDP in these examples are
defined by RFC 2327 [2]. The offers and answers are assumed to be defined by RFC 2327 [2]. The offers and answers are assumed to be
transported using a protocol such as Session Initiation Protocol transported using a protocol such as Session Initiation Protocol
(SIP) [3]. (SIP) [3].
skipping to change at page 4, line 15 skipping to change at page 4, line 15
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 8 97 m=audio 49170 RTP/AVP 0 8 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000 a=rtpmap:8 PCMA/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 32 m=video 51372 RTP/AVP 31 32
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
skipping to change at page 5, line 15 skipping to change at page 5, line 15
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 8 97 m=audio 49170 RTP/AVP 0 8 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000 a=rtpmap:8 PCMA/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 32 m=video 51372 RTP/AVP 31 32
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
skipping to change at page 6, line 27 skipping to change at page 6, line 27
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 8 97 m=audio 49170 RTP/AVP 0 8 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000 a=rtpmap:8 PCMA/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 32 m=video 51372 RTP/AVP 31 32
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 99 m=audio 49172 RTP/AVP 99
a=rtpmap:99 iLBC a=rtpmap:99 iLBC/8000
m=video 51374 RTP/AVP 31 m=video 51374 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
2.4 Two Audio Steams 2.4 Two Audio Streams
Alice offers two separate streams, one audio with two codecs and the Alice offers two separate streams, one audio with two codecs and the
other with RFC 2833 [4] tones (for DTMF). Bob accepts both audio other with RFC 2833 [4] tones (for DTMF). Bob accepts both audio
streams choosing the iLBC codec and telephone-events. streams choosing the iLBC codec and telephone-events.
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 97 m=audio 49170 RTP/AVP 0 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=audio 49172 RTP/AVP 98 m=audio 49172 RTP/AVP 98
a=rtpmap:98 telephone-event a=rtpmap:98 telephone-event/8000
a=sendonly a=sendonly
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 97 m=audio 49172 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=audio 49174 RTP/AVP 98 m=audio 49174 RTP/AVP 98
a=rtpmap:98 telephone-event a=rtpmap:98 telephone-event/8000
a=recvonly a=recvonly
2.5 Audio and Video 4 2.5 Audio and Video 4
Alice and Bob establish an audio and video session with a single Alice and Bob establish an audio and video session with a single
audio and video codec. In a second exchange, Bob changes his address audio and video codec. In a second exchange, Bob changes his address
for media and Alice accepts with the same SDP as the initial exchange for media and Alice accepts with the same SDP as the initial exchange
(and as a result does not increment the version number). (and as a result does not increment the version number).
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 m=video 51372 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49174 RTP/AVP 97 m=audio 49174 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 49170 RTP/AVP 31 m=video 49170 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Second-Offer] [Second-Offer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 newhost.biloxi.example.com c=IN IP4 newhost.biloxi.example.com
t=0 0 t=0 0
m=audio 49178 RTP/AVP 97 m=audio 49178 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 49188 RTP/AVP 31 m=video 49188 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Second-Answer] [Second-Answer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 m=video 51372 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
2.6 Audio Only 1 2.6 Audio Only 1
Alice wishes to establish an audio session with Bob using either PCMU Alice wishes to establish an audio session with Bob using either PCMU
codec or iLBC codec with RFC2833 tones, but not both at the same codec or iLBC codec with RFC2833 tones, but not both at the same
time. The offer contains these two media streams. Bob declines the time. The offer contains these two media streams. Bob declines the
first one and accepts the second one. If both media streams had been first one and accepts the second one. If both media streams had been
accepted, Alice would have sent a second declining one of the accepted, Alice would have sent a second declining one of the
skipping to change at page 9, line 17 skipping to change at page 9, line 17
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=audio 51372 RTP/AVP 97 101 m=audio 51372 RTP/AVP 97 101
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
a=rtpmap:101 telephone-events a=rtpmap:101 telephone-event/8000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 0 RTP/AVP 0 m=audio 0 RTP/AVP 0
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
m=audio 49170 RTP/AVP 97 101 m=audio 49170 RTP/AVP 97 101
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
a=rtpmap:101 telephone-events a=rtpmap:101 telephone-event/8000
2.7 Audio and Video 5 2.7 Audio and Video 5
Alice and Bob establish an audio and video session in the first Alice and Bob establish an audio and video session in the first
exchange with a single audio and video codec. In the second exchange with a single audio and video codec. In the second
exchange, Alice adds a second video codec which Bob accepts which exchange, Alice adds a second video codec which Bob accepts which
allows Alice and Bob to switch between the two video codecs without allows Alice and Bob to switch between the two video codecs without
another offer/answer exchange. another offer/answer exchange.
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 99 m=audio 49170 RTP/AVP 99
a=rtpmap:99 iLBC a=rtpmap:99 iLBC/8000
m=video 51372 RTP/AVP 31 m=video 51372 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 99 m=audio 49172 RTP/AVP 99
a=rtpmap:99 iLBC a=rtpmap:99 iLBC/8000
m=video 51374 RTP/AVP 31 m=video 51374 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Second-Offer] [Second-Offer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 99 m=audio 49170 RTP/AVP 99
a=rtpmap:99 iLBC a=rtpmap:99 iLBC/8000
m=video 51372 RTP/AVP 31 32 m=video 51372 RTP/AVP 31 32
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
[Second-Answer] [Second-Answer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 99 m=audio 49172 RTP/AVP 99
a=rtpmap:99 iLBC a=rtpmap:99 iLBC/8000
m=video 51374 RTP/AVP 31 32 m=video 51374 RTP/AVP 31 32
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
2.8 Audio and Video 6 2.8 Audio and Video 6
This scenario shows an audio and video offer that is accepted, but This scenario shows an audio and video offer that is accepted, but
the answerer wants the video sent to a different address than the the answerer wants the video sent to a different address than the
audio. This is a common scenario in conferencing where the video and audio. This is a common scenario in conferencing where the video and
audio mixing utilizes different servers. In this example, Alice audio mixing utilizes different servers. In this example, Alice
skipping to change at page 11, line 23 skipping to change at page 11, line 23
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 8 97 m=audio 49170 RTP/AVP 0 8 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000 a=rtpmap:8 PCMA/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 32 m=video 51372 RTP/AVP 31 32
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
a=rtpmap:32 MPV/90000 a=rtpmap:32 MPV/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
skipping to change at page 12, line 16 skipping to change at page 12, line 16
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 97 m=audio 49170 RTP/AVP 0 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 placeholder.biloxi.example.com c=IN IP4 placeholder.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 97 m=audio 49172 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
a=sendonly a=sendonly
[Second-Offer] [Second-Offer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Answer] [Second-Answer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49178 RTP/AVP 97 m=audio 49178 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
3.2 Hold with Two Streams 3.2 Hold with Two Streams
Alice sends but can not receive RFC2833 tones in a separate audio Alice sends but can not receive RFC2833 tones in a separate audio
stream. Bob accepts both audio streams. Bob then puts Alice's audio stream. Bob accepts both audio streams. Bob then puts Alice's audio
stream on hold but not the tone stream. Alice responds with stream on hold but not the tone stream. Alice responds with
identical SDP to the initial offer. identical SDP to the initial offer.
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 97 m=audio 49170 RTP/AVP 0 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=audio 49172 RTP/AVP 98 m=audio 49172 RTP/AVP 98
a=rtpmap:98 telephone-event a=rtpmap:98 telephone-event/8000
a=sendonly a=sendonly
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 97 m=audio 49172 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=audio 49174 RTP/AVP 98 m=audio 49174 RTP/AVP 98
a=rtpmap:98 telephone-event a=rtpmap:98 telephone-event/8000
a=recvonly a=recvonly
[Second-Offer] [Second-Offer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 97 m=audio 49172 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
a=sendonly a=sendonly
m=audio 49174 RTP/AVP 98 m=audio 49174 RTP/AVP 98
a=rtpmap:98 telephone-event a=rtpmap:98 telephone-event/8000
a=recvonly a=recvonly
[Second-Answer] [Second-Answer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 97 m=audio 49170 RTP/AVP 0 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=audio 49172 RTP/AVP 98 m=audio 49172 RTP/AVP 98
a=rtpmap:98 telephone-event a=rtpmap:98 telephone-event/8000
a=sendonly a=sendonly
4. Addition and Deletion of Media Streams 4. Addition and Deletion of Media Streams
This section shows addition and deletion of media streams. This section shows addition and deletion of media streams.
4.1 Second Audio Stream Added 4.1 Second Audio Stream Added
The second stream is added by Bob's media server (different The second stream is added by Bob's media server (different
connection address) to receive RFC 2833 telephone-events (DTMF connection address) to receive RFC 2833 telephone-events (DTMF
skipping to change at page 14, line 41 skipping to change at page 14, line 39
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 97 m=audio 49170 RTP/AVP 0 97
a=rtpmap:0 PCMU/8000 a=rtpmap:0 PCMU/8000
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Offer] [Second-Offer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=audio 48282 RTP/AVP 98 m=audio 48282 RTP/AVP 98
c=IN IP4 mediaserver.biloxi.example.com c=IN IP4 mediaserver.biloxi.example.com
a=rtpmap:98 telephone-events a=rtpmap:98 telephone-event/8000
a=recvonly a=recvonly
[Second-Answer] [Second-Answer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
c=IN IP4 host.atlanta.example.com
m=audio 49172 RTP/AVP 98 m=audio 49172 RTP/AVP 98
a=rtpmap:98 telephone-events c=IN IP4 host.atlanta.example.com
a=rtpmap:98 telephone-event/8000
a=sendonly a=sendonly
4.2 Audio then Video Added 4.2 Audio then Video Added
Audio only session is established in initial exchange between Alice Audio only session is established in initial exchange between Alice
and Bob using PCMU codec. Alice adds a video stream which is and Bob using PCMU codec. Alice adds a video stream which is
accepted by Bob. accepted by Bob.
[Offer] [Offer]
skipping to change at page 17, line 4 skipping to change at page 16, line 47
m=video 49168 RTP/AVP 31 m=video 49168 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
4.3 Audio and Video, then Video Deleted 4.3 Audio and Video, then Video Deleted
Alice and Bob establish an audio and video session. In a second Alice and Bob establish an audio and video session. In a second
exchange, Bob deletes the video session resulting in an audio only exchange, Bob deletes the video session resulting in an audio only
session. session.
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 51372 RTP/AVP 31 m=video 51372 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49174 RTP/AVP 97 m=audio 49174 RTP/AVP 97
a=rtpmap:0 PCMU/8000 a=rtpmap:97 iLBC/8000
m=video 49170 RTP/AVP 31 m=video 49170 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Second-Offer] [Second-Offer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49174 RTP/AVP 97 m=audio 49174 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 0 RTP/AVP 31 m=video 0 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
[Second-Answer] [Second-Answer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
m=video 0 RTP/AVP 31 m=video 0 RTP/AVP 31
a=rtpmap:31 H261/90000 a=rtpmap:31 H261/90000
5. Third Party Call Control (3pcc) 5. Third Party Call Control (3pcc)
This section shows examples common in Third Party Call Control (3pcc) This section shows examples common in Third Party Call Control (3pcc)
flows [5]. Call hold and resume flows are also common in 3pcc. flows [5]. Call hold and resume flows are also common in 3pcc.
5.1 No Media, then Audio Added 5.1 No Media, then Audio Added
skipping to change at page 18, line 40 skipping to change at page 18, line 40
t=0 0 t=0 0
[Second-Offer] [Second-Offer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Answer] [Second-Answer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 97 m=audio 49172 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
5.2 Hold and Unhold 2 5.2 Hold and Unhold 2
The first offer from Alice contains the connection address 0.0.0.0 The first offer from Alice contains the connection address 0.0.0.0
and a random port number, which means that Bob can not send media to and a random port number, which means that Bob can not send media to
Alice (the media stream is "black holed" or "bh"). Bob accepts with Alice (the media stream is "black holed" or "bh"). Bob accepts with
normal SDP. In the second exchange, Alice changes the connection normal SDP. In the second exchange, Alice changes the connection
address, Bob accepts, and a media session is established. address, Bob accepts, and a media session is established.
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 0.0.0.0 c=IN IP4 0.0.0.0
t=0 0 t=0 0
m=audio 23442 RTP/AVP 97 m=audio 23442 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Offer] [Second-Offer]
v=0 v=0
o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844527 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Answer] [Second-Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
5.3 Hold and Unhold 3 5.3 Hold and Unhold 3
The first offer from Alice contains an audio stream, but the answer The first offer from Alice contains an audio stream, but the answer
from Bob contains the connection address 0.0.0.0 and a random port from Bob contains the connection address 0.0.0.0 and a random port
number, which means that Alice can not send media to Bob (the media number, which means that Alice can not send media to Bob (the media
stream is "black holed" or "bh"). In the second exchange, Bob changes stream is "black holed" or "bh"). In the second exchange, Bob
the connection address, Alice accepts, and a media session is changes the connection address, Alice accepts, and a media session is
established. established.
[Offer] [Offer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Answer] [Answer]
v=0 v=0
o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844564 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 0.0.0.0 c=IN IP4 0.0.0.0
t=0 0 t=0 0
m=audio 9322 RTP/AVP 97 m=audio 9322 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Offer] [Second-Offer]
v=0 v=0
o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com o=bob 2808844564 2808844565 IN IP4 host.biloxi.example.com
s= s=
c=IN IP4 host.biloxi.example.com c=IN IP4 host.biloxi.example.com
t=0 0 t=0 0
m=audio 49172 RTP/AVP 97 m=audio 49172 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
[Second-Answer] [Second-Answer]
v=0 v=0
o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com o=alice 2890844526 2890844526 IN IP4 host.atlanta.example.com
s= s=
c=IN IP4 host.atlanta.example.com c=IN IP4 host.atlanta.example.com
t=0 0 t=0 0
m=audio 49170 RTP/AVP 97 m=audio 49170 RTP/AVP 97
a=rtpmap:97 iLBC a=rtpmap:97 iLBC/8000
6. Security Considerations 6. Security Considerations
SDP offer and answer messages can contain private information about SDP offer and answer messages can contain private information about
addresses and sessions to be established between parties. If this addresses and sessions to be established between parties. If this
information needs to be kept private, some security mechanism in the information needs to be kept private, some security mechanism in the
protocol used to carry the offers and answers must be used. For SIP, protocol used to carry the offers and answers must be used. For SIP,
this means using TLS transport and/or S/MIME encryption of the SDP this means using TLS transport and/or S/MIME encryption of the SDP
message body. message body.
7. Changes since -00 7. Changes since -00
- Added asymmetrical codec and attribute examples - Added asymmetrical codec and attribute examples
8. Changes since -01 8. Changes since -01
- Removed asymmetrical codec and attribute examples - Removed asymmetrical codec and attribute examples
- Updated references - Updated references
Informative References 9. Changes since -02
- Updated references
- Added sampling rate to iLBC rtmap lines
- Added sampling rate to telephone-event rtmap lines
- Fixed order of c= line in 4.1 Second Answer
- Fixed a= line in 4.3 Answer
10 Informative References
[1] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with [1] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with
Session Description Protocol (SDP)", RFC 3264, June 2002. Session Description Protocol (SDP)", RFC 3264, June 2002.
[2] Handley, M. and V. Jacobson, "SDP: Session Description [2] Handley, M. and V. Jacobson, "SDP: Session Description
Protocol", RFC 2327, April 1998. Protocol", RFC 2327, April 1998.
[3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., [3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A.,
Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP:
Session Initiation Protocol", RFC 3261, June 2002. Session Initiation Protocol", RFC 3261, June 2002.
[4] Schulzrinne, H. and S. Petrack, "RTP Payload for DTMF Digits, [4] Schulzrinne, H. and S. Petrack, "RTP Payload for DTMF Digits,
Telephony Tones and Telephony Signals", RFC 2833, May 2000. Telephony Tones and Telephony Signals", RFC 2833, May 2000.
[5] Rosenberg, J., Peterson, J., Schulzrinne, H. and G. Camarillo, [5] Rosenberg, J., Peterson, J., Schulzrinne, H. and G. Camarillo,
"Best Current Practices for Third Party Call Control in the "Best Current Practices for Third Party Call Control (3pcc) in
Session Initiation Protocol", draft-ietf-sipping-3pcc-06 (work the Session Initiation Protocol (SIP)", BCP 85, RFC 3725, April
in progress), January 2004. 2004.
[6] Duric, A. and S. Andersen, "RTP Payload Format for iLBC Speech", [6] Duric, A. and S. Andersen, "RTP Payload Format for iLBC Speech",
draft-ietf-avt-rtp-ilbc-04 (work in progress), December 2003. draft-ietf-avt-rtp-ilbc-04 (work in progress), December 2003.
[7] Camarillo, G., Eriksson, G., Holler, J. and H. Schulzrinne,
"Grouping of Media Lines in the Session Description Protocol
(SDP)", RFC 3388, December 2002.
Authors' Addresses Authors' Addresses
Alan Johnston Alan Johnston
MCI MCI
100 South 4th Street 100 South 4th Street
St. Louis, MO 63102 St. Louis, MO 63102
EMail: alan.johnston@mci.com EMail: alan.johnston@mci.com
Robert J. Sparks Robert J. Sparks
dynamicsoft dynamicsoft
5100 Tennyson Parkway 5100 Tennyson Parkway
Suite 1200 Suite 1200
Plano, TX 75024 Plano, TX 75024
EMail: rsparks@dynamicsoft.com EMail: rsparks@dynamicsoft.com
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