Session Initiation Protocol Service Examples :: RFC5359
Network Working Group A. Johnston, Ed.
Request for Comments: 5359 Avaya
BCP: 144 R. Sparks
Category: Best Current Practice Tekelec
C. Cunningham
S. Donovan
Cisco Systems
K. Summers
Sonus
October 2008
Session Initiation Protocol Service Examples
Status of This Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
Abstract
This document gives examples of Session Initiation Protocol (SIP)
services. This covers most features offered in so-called IP Centrex
offerings from local exchange carriers and PBX (Private Branch
Exchange) features. Most of the services shown in this document are
implemented in the SIP user agents, although some require the
assistance of a SIP proxy. Some require some extensions to SIP
including the REFER, SUBSCRIBE, and NOTIFY methods and the Replaces
and Join header fields. These features are not intended to be an
exhaustive set, but rather show implementations of common features
likely to be implemented on SIP IP telephones in a business
environment.
Johnston, et al. Best Current Practice [Page 1]
RFC 5359 SIP Service Examples October 2008
Table of Contents
1. Overview ........................................................3
1.1. Legend for Message Flows ...................................4
2. Service Examples ................................................6
2.1. Call Hold ..................................................6
2.2. Consultation Hold .........................................19
2.3. Music on Hold .............................................38
2.4. Transfer - Unattended .....................................50
2.5. Transfer - Attended .......................................58
2.6. Transfer - Instant Messaging ..............................71
2.7. Call Forwarding Unconditional .............................77
2.8. Call Forwarding - Busy ....................................84
2.9. Call Forwarding - No Answer ...............................92
2.10. 3-Way Conference - Third Party Is Added .................101
2.11. 3-Way Conference - Third Party Joins ....................107
2.12. Find-Me .................................................113
2.13. Call Management (Incoming Call Screening) ...............125
2.14. Call Management (Outgoing Call Screening) ...............132
2.15. Call Park ...............................................135
2.16. Call Pickup .............................................147
2.17. Automatic Redial ........................................154
2.18. Click to Dial ...........................................163
3. Security Considerations .......................................166
4. Acknowledgements ..............................................166
5. References ....................................................167
5.1. Normative References .....................................167
5.2. Informative References ...................................168
Johnston, et al. Best Current Practice [Page 2]
RFC 5359 SIP Service Examples October 2008
1. Overview
This document provides example call flows detailing a SIP
implementation of the following traditional telephony services:
Call Hold 3-Way Conference
Consultation Hold Find-Me
Music on Hold Incoming Call Screening
Unattended Transfer Outgoing Call Screening
Attended Transfer Call Park
Instant Messaging Transfer Call Pickup
Unconditional Call Forwarding Automatic Redial
Call Forwarding on Busy Click to Dial
Call Forwarding on No Answer
Note that the Single Line Extension call flow has been removed from
this document and will be covered in a separate document.
The call flows shown in this document were developed in the design of
a SIP IP communications network. They represent an example set of
so-called IP Centrex services or PBX services.
It is the hope of the authors that this document will be useful for
SIP implementers, designers, and protocol researchers alike and will
help further the goal of a standard implementation of RFC 3261
[RFC3261] and some of its extensions.
These flows represent carefully checked and working group reviewed
scenarios of SIP service examples as a companion to the
specifications.
These call flows are based on the current version 2.0 of SIP in RFC
3261 [RFC3261] with Session Description Protocol (SDP) usage
described in RFC 3264 [RFC3264]. Other RFCs also form part of the
SIP standard and are used and referenced in these call flows.
The SIP specification and the other referenced documents are
definitive as far as protocol issues are concerned. Also, these
flows do not represent the only way to implement these services --
other approaches such as 3pcc (Third Party Call Control) [RFC3725] or
Back-to-Back User Agents (B2BUAs) can be used. This specification
does not preclude these or other approaches for implementing such
services. The peer-to-peer design and principles of these service
examples are described in the Multiparty Framework document
[FRAMEWORK].
Johnston, et al. Best Current Practice [Page 3]
RFC 5359 SIP Service Examples October 2008
These flows assume the functionality described in the SIP Call Flow
Examples document [RFC3665], which explores basic SIP behavior. Some
of the scenarios described herein make use of the SIP method
extension REFER [RFC3515], the SIP header extension Replaces
[RFC3891], and the SIP header extension Join [RFC3911]. The SIP
Events document [RFC3265] describes the use of SUBSCRIBE and NOTIFY,
while the SIP Dialog Event Package document [RFC4235] describes the
dialog event package. Some examples make use of the GRUU (Globally
Routable User Agent URI) extension [GRUU].
These flows were prepared assuming a network of proxies, registrars,
and other SIP servers. The use of Secure SIP URIs (sips) is shown
throughout this document, implying TLS transport on each hop with
assumed certificate validation. However, other security approaches
can be used. The use of Digest authentication is shown in some
examples.
The emphasis in these call flows is the SIP signaling exchange. As a
result, only very simple SDP offer/answer exchanges are shown with
audio media. These flows apply equally well for other media and
multimedia sessions. For more advanced examples of SDP offer/answer
exchanges, refer to [RFC4317].
Each call flow is presented with a textual description of the
scenario, a message flow diagram showing the messages exchanged
between separate network elements, and the detailed contents of each
message shown in the diagram.
For simplicity in reading and editing the document, there are a
number of differences between some of the examples and actual SIP
messages. For example, the HTTP Digest responses are not actual MD5
encodings. Call-IDs are often repeated, and CSeq counts often begin
at 1. Header fields are usually shown in the same order. Usually
only the minimum required header field set is shown. Also, message
body content lengths are often not calculated, but instead shown as
"..." where the actual octet count would be.
1.1. Legend for Message Flows
Dashed lines (---) represent control messages that are mandatory to
the call scenario. These control messages can be SIP signaling.
Double dashed lines (===) represent media paths between network
elements.
Messages with parentheses around the name represent optional control
messages.
Johnston, et al. Best Current Practice [Page 4]
RFC 5359 SIP Service Examples October 2008
Messages are identified in the figures as F1, F2, etc. This
references the message details in the table that follows the figure.
Lines longer than 72 characters are handled using the
convention defined in Section 2.1 of RFC 4475 [RFC4475].
Comments in the message details are shown in the following form:
/* Comments. */
Johnston, et al. Best Current Practice [Page 5]
RFC 5359 SIP Service Examples October 2008
2. Service Examples
2.1. Call Hold
Alice Proxy Bob
| INVITE F1 | |
|--------------->| |
| | INVITE F2 |
|(100 Trying) F3 |------------->|
|<---------------| |
| |180 Ringing F4|
| 180 Ringing F5 |<-------------|
|<---------------| |
| | 200 OK F6 |
| 200 OK F7 |<-------------|
|<---------------| |
| ACK F8 | |
|--------------->| ACK F9 |
| |------------->|
| Both way RTP Established |
|<=============================>|
| |INVITE(hold) F10
|INVITE(hold) F11|<-------------|
|<---------------| |
| 200 OK F12 | |
|--------------->| 200 OK F13 |
| |------------->|
| | ACK F14 |
| ACK F15 |<-------------|
|<---------------| |
| No RTP Sent! |
| | INVITE F16 |
| INVITE F17 |<-------------|
|<---------------| |
| 200 OK F18 | |
|--------------->| 200 OK F19 |
| |------------->|
| | ACK F20 |
| ACK F21 |<-------------|
|<---------------| |
| Both way RTP Established |
|<=============================>|
| BYE F22 | |
|--------------->| BYE F23 |
| |------------->|
| | 200 OK F24 |
| 200 OK F25 |<-------------|
|<---------------| |
Johnston, et al. Best Current Practice [Page 6]
RFC 5359 SIP Service Examples October 2008
In this scenario, Alice calls Bob, then Bob places the call on hold.
Bob then takes the call off hold, then Alice hangs up the call. Note
that hold is unidirectional in nature. However, a UA that places the
other party on hold will generally also stop sending media, resulting
in no media exchange between the UAs. Older UAs may set the
connection address to 0.0.0.0 when initiating hold. However, this
behavior has been deprecated in favor or using the a=inactive SDP
attribute if no media is sent, or the a=sendonly attribute if media
is still sent.
Also note the use of the rendering feature tag defined in RFC 4235
[RFC4235] used in F10 and F11 to indicate that Bob's UA is no longer
rendering media to Bob, i.e., that Bob has placed the call on hold.
Message Details
F1 INVITE Alice -> Proxy 1
INVITE sips:bob@biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F2 INVITE Proxy 1 -> Bob
INVITE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
Via: SIP/2.0/TLS client.atlanta.example.com:5061
Johnston, et al. Best Current Practice [Page 7]
RFC 5359 SIP Service Examples October 2008
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
Max-Forwards: 69
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F3 (100 Trying) Proxy 1 -> Alice
SIP/2.0 100 Trying
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Content-Length: 0
F4 180 Ringing Bob -> Proxy 1
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Johnston, et al. Best Current Practice [Page 8]
RFC 5359 SIP Service Examples October 2008
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Content Length:0
F5 180 Ringing Proxy 1 -> Alice
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Content Length: 0
F6 200 OK Bob -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
Johnston, et al. Best Current Practice [Page 9]
RFC 5359 SIP Service Examples October 2008
F7 200 OK Proxy 1 -> Alice
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F8 ACK Alice -> Proxy 1
ACK sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf92
Route:
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F9 ACK Proxy 1 -> Bob
ACK sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837492.1
Via: SIP/2.0/TLS client.atlanta.example.com:5061
Johnston, et al. Best Current Practice [Page 10]
RFC 5359 SIP Service Examples October 2008
;branch=z9hG4bK74bf92
;received=192.0.2.103
Max-Forwards: 69
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
/* Bob places Alice on hold. Note that the version is
incremented in the o= field of the SDP. */
F10 INVITE Bob -> Proxy 1
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact: ;+sip.rendering="no"
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844528 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=sendonly
F11 INVITE Proxy 1 -> Alice
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
Johnston, et al. Best Current Practice [Page 11]
RFC 5359 SIP Service Examples October 2008
;branch=z9hG4bKnashds7
;received=192.0.2.105
Record-Route:
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact: ;+sip.rendering="no"
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844528 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=sendonly
/* Alice replies to hold. */
F12 200 OK Alice -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
Johnston, et al. Best Current Practice [Page 12]
RFC 5359 SIP Service Examples October 2008
v=0
o=alice 2890844526 2890844527 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=recvonly
F13 200 OK Proxy 1 -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844527 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=recvonly
F14 ACK Bob -> Proxy 1
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds72
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 1 ACK
Johnston, et al. Best Current Practice [Page 13]
RFC 5359 SIP Service Examples October 2008
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F15 ACK Proxy 1 -> Alice
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds72
;received=192.0.2.105
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
/* Bob takes the call off hold. */
F16 INVITE Bob -> Proxy 1
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds73
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 2 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844529 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
Johnston, et al. Best Current Practice [Page 14]
RFC 5359 SIP Service Examples October 2008
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F17 INVITE Proxy 1 -> Alice
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837493.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds73
;received=192.0.2.105
Record-Route:
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 2 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844529 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F18 200 OK Alice -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837493.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds73
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 2 INVITE
Johnston, et al. Best Current Practice [Page 15]
RFC 5359 SIP Service Examples October 2008
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844528 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F19 200 OK Proxy 1 -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds73
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 2 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844528 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F20 ACK Bob -> Proxy 1
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds74
Route:
Max-Forwards: 70
Johnston, et al. Best Current Practice [Page 16]
RFC 5359 SIP Service Examples October 2008
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 2 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F21 ACK Proxy 1 -> Alice
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837494.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds74
;received=192.0.2.105
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345601@atlanta.example.com
CSeq: 2 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
/* RTP Media stream re-established. Alice disconnects. */
F22 BYE Alice -> Proxy 1
BYE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf97
Route:
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
F23 BYE Proxy 1 -> Bob
BYE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837497.1
Johnston, et al. Best Current Practice [Page 17]
RFC 5359 SIP Service Examples October 2008
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf97
;received=192.0.2.103
Max-Forwards: 69
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
F24 200 OK Bob -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837497.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf97
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
F25 200 OK Proxy 1 -> Alice
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf97
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345601@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
Johnston, et al. Best Current Practice [Page 18]
RFC 5359 SIP Service Examples October 2008
2.2. Consultation Hold
Alice Proxy Bob Carol
| | | |
| INVITE F1 | | |
|--------------->| INVITE F2 | |
| |------------->| |
|(100 Trying) F3 | | |
|<---------------|180 Ringing F4| |
| |<-------------| |
| 180 Ringing F5 | | |
|<---------------| 200 OK F6 | |
| |<-------------| |
| 200 OK F7 | | |
|<---------------| | |
| ACK F8 | | |
|--------------->| ACK F9 | |
| |------------->| |
| Both way RTP Established | |
|<=============================>| |
| |INVITE(hold) F10 |
|INVITE(hold) F11|<-------------| |
|<---------------| | |
| 200 OK F12 | | |
|--------------->| 200 OK F13 | |
| |------------->| |
| | ACK F14 | |
| |<-------------| |
| ACK F15 | | |
|<---------------| | |
| No RTP Sent! | |
| | INVITE F16 | |
| |<-------------| |
| | | INVITE F17 |
| |--------------------------------->|
| |(100 Trying) F18 |
| |------------->| |
| | | 180 Ringing F19 |
| |<---------------------------------|
| | 180 Ringing F20 |
| |------------->| |
| | | 200 OK F21 |
| |<---------------------------------|
| | 200 OK F22 | |
| |------------->| |
| | ACK F23 | |
| |<-------------| |
| | | ACK F24 |
Johnston, et al. Best Current Practice [Page 19]
RFC 5359 SIP Service Examples October 2008
| |--------------------------------->|
| | Both way RTP Established |
| | |<=================>|
| | BYE F25 | |
| |<-------------| |
| | | BYE F26 |
| |--------------------------------->|
| | | 200 OK F27 |
| |<---------------------------------|
| | 200 OK F28 | |
| |------------->| |
| | INVITE F29 | |
| INVITE F30 |<-------------| |
|<---------------| | |
| 200 OK F31 | | |
|--------------->| 200 OK F32 | |
| |------------->| |
| | ACK F33 | |
| |<-------------| |
| ACK F34 | | |
|<---------------| | |
| Both way RTP Established | |
|<=============================>| |
| BYE F35 | | |
|--------------->| BYE F36 | |
| |------------->| |
| | 200 OK F37 | |
| |<-------------| |
| 200 OK F38 | | |
|<---------------| | |
| | | |
In this scenario, Alice calls Bob. Bob places call on hold. Bob
calls Carol. Bob then disconnects with Carol, then takes the call
with Alice off hold. The call ends when Alice hangs up.
Also note the use of the rendering feature tag defined in RFC 4235
[RFC4235] used in F10 to indicate that Bob's UA is no longer
rendering media to Bob, i.e., that Bob has placed the call on hold.
Message Details
F1 INVITE Alice -> Proxy 1
INVITE sips:bob@biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
Max-Forwards: 70
Johnston, et al. Best Current Practice [Page 20]
RFC 5359 SIP Service Examples October 2008
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F2 INVITE Proxy 1 -> Bob
INVITE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
Max-Forwards: 69
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
Johnston, et al. Best Current Practice [Page 21]
RFC 5359 SIP Service Examples October 2008
F3 (100 Trying) Proxy 1 -> Alice
SIP/2.0 100 Trying
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Content-Length: 0
F4 180 Ringing Bob -> Proxy 1
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Content Length:0
F5 180 Ringing Proxy 1 -> Alice
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Content Length: 0
Johnston, et al. Best Current Practice [Page 22]
RFC 5359 SIP Service Examples October 2008
F6 200 OK Bob -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F7 200 OK Proxy 1 -> Alice
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
Record-Route:
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
Johnston, et al. Best Current Practice [Page 23]
RFC 5359 SIP Service Examples October 2008
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F8 ACK Alice -> Proxy 1
ACK sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf45
Route:
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F9 ACK Proxy 1 -> Bob
ACK sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837494.1
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf45
;received=192.0.2.103
Max-Forwards: 69
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
Johnston, et al. Best Current Practice [Page 24]
RFC 5359 SIP Service Examples October 2008
/* Bob places Alice on hold. */
F10 INVITE Bob -> Proxy 1
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact: ;+sip.rendering="no"
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844528 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=sendonly
F11 INVITE Proxy 1 -> Alice
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837497.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
;received=192.0.2.105
Record-Route:
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact: ;+sip.rendering="no"
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
Johnston, et al. Best Current Practice [Page 25]
RFC 5359 SIP Service Examples October 2008
v=0
o=bob 2890844527 2890844528 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=sendonly
F12 200 OK Alice -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK837497.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844527 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=recvonly
F13 200 OK Proxy 1 -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
Johnston, et al. Best Current Practice [Page 26]
RFC 5359 SIP Service Examples October 2008
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844527 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=recvonly
F14 ACK Bob -> Proxy 1
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashdsg
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F15 ACK Proxy 1 -> Alice
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK8374.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashdsg
;received=192.0.2.105
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Johnston, et al. Best Current Practice [Page 27]
RFC 5359 SIP Service Examples October 2008
Call-ID: 12345600@atlanta.example.com
CSeq: 1 ACK
Content-Length: 0
F16 INVITE Bob -> Proxy 1
INVITE sips:carol@chicago.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
Max-Forwards: 70
From: Bob ;tag=8675309
To: Carol
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844834 2890844834 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 50170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F17 INVITE Proxy 1 -> Carol
INVITE sips:carol@client.chicago.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749a.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
;received=192.0.2.105
Record-Route:
Max-Forwards: 69
From: Bob ;tag=8675309
To: Carol
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Johnston, et al. Best Current Practice [Page 28]
RFC 5359 SIP Service Examples October 2008
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844834 2890844834 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 50170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F18 (100 Trying) Proxy 1 -> Bob
SIP/2.0 100 Trying
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
;received=192.0.2.105
From: Bob ;tag=8675309
To: Carol
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 INVITE
Content-Length: 0
F19 180 Ringing Carol -> Proxy 1
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749a.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
;received=192.0.2.105
Record-Route:
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@atlanta.example.com
CSeq: 1 INVITE
Contact:
Content Length:0
F20 180 Ringing Proxy 1 -> Bob
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
Johnston, et al. Best Current Practice [Page 29]
RFC 5359 SIP Service Examples October 2008
;received=client.chicago.example.com
Record-Route:
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 INVITE
Contact:
Content Length: 0
F21 200 OK Carol -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749a.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
;received=192.0.2.105
Record-Route:
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=carol 2890844922 2890844922 IN IP4 client.chicago.example.com
s=
c=IN IP4 client.chicago.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F22 200 OK Proxy 1 -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds22
;received=192.0.2.105
Record-Route:
From: Bob ;tag=8675309
To: Carol ;tag=456654
Johnston, et al. Best Current Practice [Page 30]
RFC 5359 SIP Service Examples October 2008
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=carol 2890844922 2890844922 IN IP4 client.chicago.example.com
s=
c=IN IP4 client.chicago.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F23 ACK Bob -> Proxy 1
ACK sips:carol@client.chicago.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds24
Route:
Max-Forwards: 70
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F24 ACK Proxy 1 -> Carol
ACK sips:carol@client.chicago.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749b.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds24
;received=192.0.2.105
Max-Forwards: 69
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 1 ACK
Johnston, et al. Best Current Practice [Page 31]
RFC 5359 SIP Service Examples October 2008
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F25 BYE Bob -> Proxy 1
BYE sips:carol@client.chicago.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7j
Route:
Max-Forwards: 70
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 2 BYE
Content-Length: 0
F26 BYE Proxy 1 -> Carol
BYE sips:carol@client.chicago.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749k.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7j
;received=192.0.2.105
Max-Forwards: 69
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 2 BYE
Content-Length: 0
F27 200 OK Carol -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749k.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7j
;received=192.0.2.105
From: Bob ;tag=8675309
To: Carol ;tag=456654
Johnston, et al. Best Current Practice [Page 32]
RFC 5359 SIP Service Examples October 2008
Call-ID: 9876543210@biloxi.example.com
CSeq: 2 BYE
Content-Length: 0
F28 200 OK Proxy 1 -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7j
;received=192.0.2.105
From: Bob ;tag=8675309
To: Carol ;tag=456654
Call-ID: 9876543210@biloxi.example.com
CSeq: 2 BYE
Content-Length: 0
/* Bob takes the call off hold. */
F29 INVITE Bob -> Proxy 1
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7b
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 2 INVITE
Contact:
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844529 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
Johnston, et al. Best Current Practice [Page 33]
RFC 5359 SIP Service Examples October 2008
F30 INVITE Proxy 1 -> Alice
INVITE sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749q.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7b
;received=192.0.2.105
Record-Route:
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 2 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844529 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F31 200 OK Alice -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK83749q.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7b
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 2 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
Johnston, et al. Best Current Practice [Page 34]
RFC 5359 SIP Service Examples October 2008
v=0
o=alice 2890844526 2890844528 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F32 200 OK Proxy 1 -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7b
;received=192.0.2.105
Record-Route:
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 2 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844528 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F33 ACK Bob -> Proxy 1
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7d7
Route:
Max-Forwards: 70
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 2 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Johnston, et al. Best Current Practice [Page 35]
RFC 5359 SIP Service Examples October 2008
Content-Length: 0
F34 ACK Proxy 1 -> Alice
ACK sips:alice@client.atlanta.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK8374.1
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds7d7
;received=192.0.2.105
Max-Forwards: 69
From: Bob ;tag=314159
To: Alice ;tag=1234567
Call-ID: 12345600@atlanta.example.com
CSeq: 2 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
F35 BYE Alice -> Proxy 1
BYE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf10
Route:
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
F36 BYE Proxy 1 -> Bob
BYE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK8379.1
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf10
;received=192.0.2.103
Max-Forwards: 69
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
Johnston, et al. Best Current Practice [Page 36]
RFC 5359 SIP Service Examples October 2008
F37 200 OK Bob -> Proxy 1
SIP/2.0 200 OK
Via: SIP/2.0/TLS ss1.example.com:5061
;branch=z9hG4bK8379.1
;received=192.0.2.54
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf10
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
F38 200 OK Proxy 1 -> Alice
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf10
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob ;tag=314159
Call-ID: 12345600@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
Johnston, et al. Best Current Practice [Page 37]
RFC 5359 SIP Service Examples October 2008
2.3. Music on Hold
Alice Bob Music Server
| | |
| INVITE F1 | |
|--------------->| |
| 180 Ringing F2 | |
|<---------------| |
| 200 OK F3 | |
|<---------------| |
| ACK F4 | |
|--------------->| |
| RTP | |
|<==============>| |
| | |
| Bob places Alice on hold |
| | |
| INVITE (hold) F5 |
|<---------------| |
| 200 OK F6 | |
|--------------->| |
| ACK F7 | |
|<---------------| |
| no RTP | |
| | |
| Bob initiates music on hold |
| | |
| | REFER Refer-To: A F8
| |------------->|
| | 202 F9 |
| |<-------------|
| | NOTIFY F10 |
| |<-------------|
| | 200 F11 |
| |------------->|
| INVITE F12 Replaces: B |
|<------------------------------|
| 200 OK F13 |
|------------------------------>|
| ACK F14 |
|<------------------------------|
| RTP Music |
|<==============================|
| BYE F15 | |
|--------------->| NOTIFY F17 |
| 200 OK F16 |<-------------|
|<---------------| 200 OK F18 |
| |------------->|
Johnston, et al. Best Current Practice [Page 38]
RFC 5359 SIP Service Examples October 2008
| | |
| The music on hold is complete |
| | |
| Bob takes Alice off hold |
| | |
| INVITE Replaces: M F19 |
|<---------------| |
| 200 OK F20 | |
|--------------->| |
| ACK F21 | |
|<---------------| |
| RTP | |
|<==============>| |
| BYE F22 |
|------------------------------>|
| 200 OK F23 |
|<------------------------------|
In this flow, Bob places Alice on hold with music. This is performed
by Bob sending a REFER to a Music Server that sends an INVITE with
Replaces to Alice. The Music Server then sends RTP music to Alice.
Bob picks the call up from hold by sending an INVITE with Replaces to
Alice.
Note the use of the rendering feature tag defined in RFC 4235
[RFC4235] used in F5 to indicate that Bob's UA is no longer rendering
media to Bob, i.e., that Bob has placed the call on hold. Feature
tags are also used in F12 with the automaton (defined in RFC 3840
[RFC3840]) and byeless feature tags (defined in RFC 4235 [RFC4235])
to describe the capabilities of the Music Server.
Should Alice not wish to receive music on hold, her UA could refuse
F12 and she will remain on hold with Bob, but in silence.
Message Details
F1 INVITE Alice -> Bob
INVITE sips:bob@biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Johnston, et al. Best Current Practice [Page 39]
RFC 5359 SIP Service Examples October 2008
Supported: replaces, gruu
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F2 180 Ringing Bob -> Alice
SIP/2.0 180 Ringing
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Content-Length: 0
F3 200 OK Bob -> Alice
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
From: Alice ;tag=1234567
To: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
Johnston, et al. Best Current Practice [Page 40]
RFC 5359 SIP Service Examples October 2008
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
F4 ACK Alice -> Bob
ACK sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bK74bfd
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 1 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
/* Bob places Alice on hold. */
F5 INVITE Bob -> Alice
INVITE sips:a8342043f@atlanta.example.com;gr SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bK874bk
To: Alice ;tag=1234567
From: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 712 INVITE
Contact: ;+sip.rendering="no"
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=bob 2890844527 2890844528 IN IP4 client.biloxi.example.com
s=
c=IN IP4 client.biloxi.example.com
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=sendonly
Johnston, et al. Best Current Practice [Page 41]
RFC 5359 SIP Service Examples October 2008
F6 200 OK Alice -> Bob
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bK874bk
;received=192.0.2.105
To: Alice ;tag=1234567
From: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 712 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces, gruu
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844527 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=recvonly
F7 ACK Bob -> Alice
ACK sips:a8342043f@atlanta.example.com;gr SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKq874b
To: Alice ;tag=1234567
From: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 712 ACK
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY
Supported: replaces
Content-Length: 0
/* Bob REFERs Music Server to establish session with Alice
which replaces the established session between Alice and Bob. */
F8 REFER Bob -> Music Server
REFER sips:music@server.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds9
Johnston, et al. Best Current Practice [Page 42]
RFC 5359 SIP Service Examples October 2008
Max-Forwards: 70
From: Bob ;tag=02134
To: Music Server
Call-ID: 4802029847@biloxi.example.com
CSeq: 1 REFER
Refer-To:
Referred-By:
Contact:
Content-Length: 0
F9 202 Accepted Music Server -> Bob
SIP/2.0 202 Accepted
Via: SIP/2.0/TLS client.biloxi.example.com:5061
;branch=z9hG4bKnashds9
;received=192.0.2.105
From: Bob ;tag=02134
To: Music Server ;tag=56323
Call-ID: 4802029847@biloxi.example.com
Contact:
CSeq: 1 REFER
Content-Length: 0
F10 NOTIFY Music Server -> Bob
NOTIFY sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74bT6
To: Bob ;tag=02134
Max-Forwards: 70
From: Music Server ;tag=56323
Call-ID: 4802029847@biloxi.example.com
CSeq: 1 NOTIFY
Event: refer
Subscription-State: active;expires=60
Contact:
Content-Type: message/sipfrag
Content-Length: ...
SIP/2.0 100 Trying
Johnston, et al. Best Current Practice [Page 43]
RFC 5359 SIP Service Examples October 2008
F11 200 OK Bob -> Music Server
SIP/2.0 200 OK
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74bT6
;received=192.0.2.103
To: Bob ;tag=02134
From: Music Server ;tag=56323
Call-ID: 4802029847@biloxi.example.com
CSeq: 1 NOTIFY
Content-Length: 0
/* Music Server places call to Alice to replace session
between Alice and Bob. */
F12 INVITE Music Server -> Alice
INVITE sips:a8342043f@atlanta.example.com;gr SIP/2.0
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74rf
Max-Forwards: 70
From: ;tag=0111
To:
Call-ID: a5-75-34-12-76@server.example.com
CSeq: 1 INVITE
Referred-By:
Contact: ;automaton
;+sip.byeless;+sip.rendering="no"
Require: replaces
Replaces: 12345600@atlanta.example.com
;from-tag=23431;to-tag=1234567
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY
Supported: replaces
Content-Type: application/sdp
Content-Length: ...
v=0
o=MusicServer 2890844576 2890844576 IN IP4 server.example.com
s=
c=IN IP4 server.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=sendonly
Johnston, et al. Best Current Practice [Page 44]
RFC 5359 SIP Service Examples October 2008
F13 200 OK Alice -> Music Server
SIP/2.0 200 OK
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74rf
;received=192.0.2.103
From: ;tag=0111
To: ;tag=098594
Call-ID: a5-75-34-12-76@server.example.com
CSeq: 1 INVITE
Contact:
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY
Supported: replaces, gruu
Content-Type: application/sdp
Content-Length: ...
v=0
o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com
s=
c=IN IP4 client.atlanta.example.com
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000
a=recvonly
F14 ACK Music Server -> Alice
ACK sips:a8342043f@atlanta.example.com;gr SIP/2.0
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK7rfF
Max-Forwards: 70
From: ;tag=0111
To: ;tag=098594
Call-ID: a5-75-34-12-76@server.example.com
CSeq: 1 ACK
Content-Length: 0
F15 BYE Alice -> Bob
BYE sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bKnashds7
Max-Forwards: 70
From: Alice ;tag=1234567
To: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
Johnston, et al. Best Current Practice [Page 45]
RFC 5359 SIP Service Examples October 2008
CSeq: 2 BYE
Content-Length: 0
F16 200 OK Bob -> Alice
SIP/2.0 200 OK
Via: SIP/2.0/TLS client.atlanta.example.com:5061
;branch=z9hG4bKnashds7
;received=192.0.2.105
From: Alice ;tag=1234567
To: Bob ;tag=23431
Call-ID: 12345600@atlanta.example.com
CSeq: 2 BYE
Content-Length: 0
/* Music Server reports success back to Bob by returning
a 200 OK response. Bob obtains the dialog identifiers
from the headers included in the response. */
F17 NOTIFY Music Server -> Bob
NOTIFY sips:bob@client.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74bf9
To: Bob ;tag=02134
Max-Forwards: 70
From: Music Server ;tag=56323
Call-ID: 4802029847@biloxi.example.com
CSeq: 2 NOTIFY
Event: refer
Subscription-State: terminated;reason=noresource
Contact:
Content-Type: message/sipfrag
Content-Length: ...
SIP/2.0 200 OK
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74rf
;received=192.0.2.103
From: ;tag=0111
To: ;tag=098594
Call-ID: a5-75-34-12-76@server.example.com
CSeq: 1 INVITE
Contact:
Johnston, et al. Best Current Practice [Page 46]
RFC 5359 SIP Service Examples October 2008
F18 200 OK Bob -> Music Server
SIP/2.0 200 OK
Via: SIP/2.0/TLS server.example.com:5061
;branch=z9hG4bK74bf9
;received=192.0.2.103
To: Bob 