As per Relevance of the word appropriate, we have this rfc below:

---

Network Working Group B.
Request for Comments: 3087 R.
Category: Informational
April 2001


Control of Service Context using SIP Request-

Status of this

This memo provides information for the Internet community. It
not specify an Internet standard of any kind. Distribution of
memo is unlimited

Copyright

Copyright (C) The Internet Society (2001). All Rights Reserved



This memo provides information for the Internet community.
describes a useful way to conceptualize the use of the standard
(Session Initiation Protocol) Request-URI (Uniform
Identifier) that the authors and many members of the SIP
think is suitable as a convention. It does not define any
protocol with respect to RFC 2543.

In a conventional telephony environment, extended
applications often use call state information, such as calling party
called party, reason for forward, etc, to infer application context
In a SIP/2.0 call, much of this information may be either non
existent or unreliable. This document proposes a mechanism
communicate context information to an application. Under
proposal, a client or proxy can communicate context through the
of a distinctive Request-URI. This document continues with
of how this mechanism could be used in a voice mail application















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RFC 3087 SIP Service Control April 2001


Table of

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . 3
2. Example Application . . . . . . . . . . . . . . . . . . . 3
2.1 Using URIs to Control Voice Mail Service Behavior . . . . 3
3. Voice Mail Scenario Descriptions . . . . . . . . . . . . . 5
3.1 Deposits . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1 Direct Request to Deposit to a particular mailbox . . . . 5
3.1.1.1 SIP source . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.1.2 Arbitrary PSTN source . . . . . . . . . . . . . . . . . . 5
3.1.1.3 Recognized PSTN source . . . . . . . . . . . . . . . . . . 6
3.1.2 Direct Request to Deposit, mailbox to be determined . . . 6
3.1.2.1 SIP source . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.2.2 PSTN source . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.2.3 Indirect Request to Deposit, due to find-me proxy decision 6
3.2 Retrievals . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.1 Request to Retrieve from a particular mailbox . . . . . . 7
3.2.1.1 Trusted SIP source . . . . . . . . . . . . . . . . . . . . 7
3.2.1.2 Authenticated SIP source . . . . . . . . . . . . . . . . . 7
3.2.1.3 Unauthenticated SIP source . . . . . . . . . . . . . . . . 7
3.2.1.4 PSTN source . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.2 Request to Retrieve, mailbox to be determined . . . . . . 7
3.2.2.1 SIP source . . . . . . . . . . . . . . . . . . . . . . . . 7
3.2.2.2 Arbitrary PSTN source . . . . . . . . . . . . . . . . . . 8
3.2.2.3 Recognized PSTN source . . . . . . . . . . . . . . . . . . 8
4. Voice Mail Call Flow Examples . . . . . . . . . . . . . . 8
4.1 Generic Scenario . . . . . . . . . . . . . . . . . . . . . 8
4.1.1 Direct call to the voice mail system . . . . . . . . . . . 8
4.2 Message Deposit Scenarios . . . . . . . . . . . . . . . . 13
4.2.1 Call to known subscriber forwarded on no answer . . . . . 13
4.2.2 Call to known subscriber forwarded on busy . . . . . . . . 19
4.2.3 Direct call to a subscriber's mailbox . . . . . . . . . . 24
4.3 Message Retrieval Scenarios . . . . . . . . . . . . . . . 29
4.3.1 Call to retrieve messages believed to be from a
subscriber . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3.2 Call to retrieve messages from an authenticated subscriber 33
5. Security Considerations . . . . . . . . . . . . . . . . . 38
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . 38
References . . . . . . . . . . . . . . . . . . . . . . . . 38
Authors' Addresses . . . . . . . . . . . . . . . . . . . . 38
Full Copyright Statement . . . . . . . . . . . . . . . . . 39










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1.

A communication service should make use of the information it has
hand when being accessed. For example, in most current voice
implementations, a subscriber retrieving messages from his own
does not have to reenter his voice mailbox number - the
assumes that the store being accessed is the one associated with
endpoint being used to access the service. Some services allow
user to validate this assumption using IVR techniques
prompting for a PIN

This concept of context-awareness can be captured in a voice
service implementing SIP as defined in RFC 2543[1],
modification, through the standard use of that protocol's Request
URI. Furthermore, the concept is applicable to any SIP-based
where initial application state should be determined from context

This concept is a usage convention of standard SIP as defined in
2543[1] and does not modify or extend that protocol in any way

2. Example

In this document, we use the example of voice mail to illustrate
technique. One motivation for applying this technique to
problem is allowing a proxy or location server to control the
state of a voice service. For example, a voice client might
a contact list ending with the URL that would accept voice
for the client

2.1 Using URIs to Control Voice Mail Service

Many conventional voice mail systems use call state information,
as the calling party, called party, reason for forward, etc,
decide the initial application state. For example, it might play
outgoing message if the call reached voice mail because the
party did not answer and another if the line was busy. It
whom the message is for based on the called party information.
the call originated from a subscriber's phone number, it
authenticate the caller and then go directly to the message
and account maintenance menu

When a new subscriber is added to a system, a set of identities
be generated, each given a unique sip URI. The following tables
some of the identities that might be generated (it is
exhaustive). The example schemes show that the URIs could, but don'
necessarily have to, have mnemonic value





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In practical applications, it is important that an application
not apply semantic rules to the various URIs. Instead, it
allow any arbitrary string to be provisioned, and map the string
the desired behavior. The owner of the system may choose
provision mnemonic strings, but the application should not
it. In any large installation, the system owner is likely to
pre-existing rules for mnemonic URIs, and any attempt by
application to define its own rules may create a conflict. For
example, this means a voice mail system should allow an arbitrary
of URLs from these schemes, or any other scheme that renders
SIP URIs to be provisioned, rather than enforce one
scheme

URI Identity Example Scheme 1
Example Scheme 2
Example Scheme 3

Deposit with sip:sub-rjs-deposit@vm.wcom.
standard greeting sip:677283@vm.wcom.
sip:rjs@vm.wcom.com;mode=


Deposit with on sip:sub-rjs-deposit-busy.vm.wcom.
phone greeting sip:677372@vm.wcom.
sip:rjs@vm.wcom.com;mode=3991243

Deposit with sip:sub-rjs-deposit-sg@vm.wcom.
special greeting sip:677384@vm.wcom.
sip:rjs@vm.wcom.com;mode=

Retrieve - SIP sip:sub-rjs-retrieve@vm.wcom.
authentication sip:677405@vm.wcom.
sip:rjs@vm.wcom.com;mode=

Retrieve - prompt sip:sub-rjs-retrieve-inpin.vm.wcom.
for PIN in-band sip:677415@vm.wcom.
sip:rjs@vm.wcom.com;mode=

When a service is first set up, identities such as the
could be created

URI Identity Example Scheme 1
Example Scheme 2
Example Scheme 3

Deposit - sip:deposit@vm.wcom.
identify target sip:670001@vm.wcom.
mailbox by To: sip:deposit@vm.wcom.



Campbell & Sparks Informational [Page 4]

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Retrieve - sip:retrieve@vm.wcom.
identify target sip:670002@vm.wcom.
mailbox by SIP sip:retrieve@vm.wcom.


Deposit - prompt sip:deposit-in@vm.wcom.
for target sip:670003@vm.wcom.
mailbox in-band sip:deposit@vm.wcom.com;mode=

Retrieve - prompt sip:retrieve-in@vm.wcom.
for target sip:670004@vm.wcom.
mailbox and PIN sip:retrieve@vm.wcom.com;mode=
in-

In addition to providing this set of URIs to the subscriber (to
as he sees fit), an integrated service provider could add these
the set of contacts in a find-me proxy. The proxy could then
calls to the appropriate URI based on the origin of the request,
subscriber's preferences and current state

3. Voice Mail Scenario

In each of these scenarios, the PSTN gateway is configured
communicate only with a particular proxy-registrar

3.1

3.1.1 Direct Request to Deposit to a particular

3.1.1.1 SIP

A SIP client that knew the URI for a particular deposit
(sip:sub-rjs-deposit@vm.wcom.com) could place a direct invitation
the voicemail service, or through a protecting proxy. The
could restrict access to deposit identities with special greetings
authenticating the requester

3.1.1.2 Arbitrary PSTN

The gateway's proxy would map a call from an unrecognized PSTN
to a number associated with a subscriber's mailbox into an invite
the deposit with standard greeting URI (sip:sub-rjs
deposit@vm.wcom.com).








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3.1.1.3 Recognized PSTN

The gateway's proxy would map a call from a recognized (exact
pattern match) PSTN number to a number associated with a subscriber'
mailbox into an invite to the appropriate special greeting
(sip:sub-rjs-deposit-sg@vm.wcom.com). The gateway's ability
identify the calling party (using calling party number) is trusted
so no further authentication of the requester is performed

3.1.2 Direct Request to Deposit, mailbox to be

3.1.2.1 SIP

A voice mail service or its protecting proxy could expose a
deposit URL for use when a caller wished to go directly to
mail. The service would likely play an IVR dialog to determine
message store to deposit a message into

An application designer may be tempted to attempt to match the To
and From: headers on a call to infer information. However,
approach could cause complications when multiple proxy forwards
in a call. For example, A calls B, who has all calls forwarded to C
C forwards the call to her voice mail service. If the voice
service matches the To: header to determine the message store,
will get the information for B instead of C. But there is no
to assume that C's voice mail service has any knowledge of B

3.1.2.2 PSTN

The gateway's proxy would map a call from an unrecognized PSTN
to the top level voice mail service access number to an invite to
Deposit - prompt for target mailbox in-band URI (sip:deposit
in@vm.wcom.com for example). Getting the call to the target
would proceed as in the SIP source case

3.1.2.3 Indirect Request to Deposit, due to find-me proxy

A find-me proxy could map an invitation to a
(sip:rjs@wcom.com) to the appropriate voice mail service
depending on the subscriber's current state. The normal deposit
could be chosen if the subscriber's contact list has been
exhausted with no answer. The busy-announcement URI would be
when a busy everywhere response is received from one of the contacts
A DND announcement URI could be selected if the subscriber
activated DND. Calls to sip:receptionist@wcom.com could be
to roll to sip:deposit@wcom.





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RFC 3087 SIP Service Control April 2001


3.2

3.2.1 Request to Retrieve from a particular

3.2.1.1 Trusted SIP

A request to retrieve the contents of a particular mailbox (sip:sub
rjs-retrieve@vm.wcom.com) coming from a trusted source could
honored without further authentication checks. A trusted source
one with which the voice mail service has secure communications,
to which it is willing to delegate authentication. This could be
service's protecting proxy for example

3.2.1.2 Authenticated SIP

A service, or its protecting proxy, could choose to honor a
request for a particular mailbox (sip:sub-rjs-retrieve@vm.wcom.com
based on SIP authentication. If SIP level authentication failed,
service or proxy could be configured to send the call to the in-
pin prompting URI (sip:sub-rjs-retrieve-inpin@vm.wcom.com).

3.2.1.3 Unauthenticated SIP

A service, or its protecting proxy, receiving a retrieve request
a particular mailbox (sip:sub-rjs-retrieve@vm.wcom.com) with no
method of authenticating the requestor could send the request to
in-band pin prompting URI (sip:sub-rjs-retrieve-inpin@vm.wcom.com).

3.2.1.4 PSTN

This scenario assumes that the service provider's network has
configured such that a PSTN number could be dialed explicitly
retrieving messages from a particular mailbox. Such
currently exist, but are not common. In such a network,
gateway's proxy would map the call to the in-band pin prompting
(sip:sub-rjs-retrieve-inpin@vm.wcom.com).

3.2.2 Request to Retrieve, mailbox to be

3.2.2.1 SIP

As in the Request to Deposit scenario, when a service receives
request for the top level retrieve URI it would most likely need
use in-band IVR techniques to determine the target mailbox
authenticate the caller






Campbell & Sparks Informational [Page 7]

RFC 3087 SIP Service Control April 2001


3.2.2.2 Arbitrary PSTN

This scenario assumes there is a single PSTN number that
dial to access the voice mail service to retrieve messages. This
the most common access method provided by current voice
services

The gateway's proxy would map a call to the top level PSTN number
the top level retrieve in-band prompting URI (sip:retrieve
in@vm.wcom.com). Once the system identifies the target mailbox,
call would be transferred to the appropriate in-band pin
URI (sip:sub-rjs-retrieve-inpin@vm.wcom.com).

3.2.2.3 Recognized PSTN

This scenario also assumes there is a single PSTN number
subscribers dial to access the voice mail service to
messages

The gateway's proxy would recognize the calling party number as
subscriber, and map the call to the subscriber's in-band
URI (sip:sub-rjs-retrieve-inpin@vm.wcom.com

4. Voice Mail Call Flow

The following section describes some example call flows for
hypothetical voice mail service, with the host name of vm.wcom.com
All the call flows assume that a proxy protects the voice
service and that a trust relationship exists between the voice
service and the proxy

4.1 Generic

4.1.1 Direct call to the voice mail

User A calls the voice mail system directly. The voice mail
invokes the top-level menu, which might prompt the caller for
extension or the first few letters of a name













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User A Proxy VM
| | |
| INVITE F1 | |
|------------------>| |
| | INVITE F2 |
| (100 Trying) F3 |---------------------->|
|<------------------| |
| | 180 Ringing F4 |
| 180 Ringing F5 |<----------------------|
|<------------------| |
| | 200 OK F6 |
| 200 OK F6 |<----------------------|
|<------------------| |
| | |
| ACK F8 | |
|------------------>| ACK F9 |
| |---------------------->|
| | |
| RTP Established- Play top level menu |
|<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->|
| | |
| BYE F10 | |
|------------------>| BYE F11 |
| |---------------------->|
| | |
| | 200 OK F12 |
| |<----------------------|
| 200 OK F13 | |
|<------------------| |
| | |


Flow Id

INVITE F1 INVITE sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Proxy-Authorization:Digest username="UserA",
realm="MCI WorldCom SIP",
nonce="ea9c8e88df84f1cc4e341ae6cbe5a359", opaque="",
uri="sip:VoiceMail@wcom.com", response=<
calculated hash goes here
Content-Type: application/
Content-Length: <appropriate value



Campbell & Sparks Informational [Page 9]

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v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

/*Client for A prepares to receive data on port 49170
from the network. */

INVITE F2 INVITE sip:top@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

(100 Trying SIP/2.0 100
F3 Via: SIP/2.0/UDP here.com:5060
Proxy->A) From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

180 Ringing SIP/2.0 180
F4 Via: SIP/2.0/UDP wcom.com:5060; branch=1
VM->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0




Campbell & Sparks Informational [Page 10]

RFC 3087 SIP Service Control April 2001


180 Ringing SIP/2.0 180
F5 Via: SIP/2.0/UDP here.com:5060
Proxy->A From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

200 OK F6 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact: VoiceMailSystem Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000


200 OK F7 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact VoiceMailSystem Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000




Campbell & Sparks Informational [Page 11]

RFC 3087 SIP Service Control April 2001


ACK F8 ACK sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F9 ACK sip:top@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ; tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

/* RTP streams are established between A and VM.
system starts IVR dialog for top level menu */

/* User A Hangs Up with VM system. Alternatively,
VM system could initiate the BYE*/

BYE F10 BYE sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

BYE F11 BYE sip: top@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F12 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.



Campbell & Sparks Informational [Page 12]

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CSeq: 2
Content-Length: 0

200 OK F13 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

4.2 Message Deposit

4.2.1 Call to known subscriber forwarded on no

User A attempts to call UserB, who does not answer. The call
forwarded to UserB's mailbox, and the voice mail system plays UserB'
outgoing message for a ring-no-answer. The flow assumes that the
of "sip:UserB-dep-fna@vm.wcom.com maps" to the desired behavior
depositing a message on a forward-no-answer































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RFC 3087 SIP Service Control April 2001


User A Proxy User B VM
| | | |
| INVITE F1 | | |
|---------------->| INVITE F2 | |
| |----------------->| |
| (100 Trying) F3 | | |
|<----------------| 180 Ringing F4 | |
| |<-----------------| |
| 180 Ringing F5 | | |
|<----------------| (Request Timeout)| |
| | | |
| | Cancel F6 | |
| |----------------->| |
| | | |
| | 200 OK F7 | |
| |<-----------------| |
| | | |
| | INVITE F8 |
| |---------------------------------->|
| | | |
| | 200 OK F9| |
| 200 OK F10 |<----------------------------------|
|<----------------| | |
| | | |
| ACK F11 | | |
|---------------->| ACK F12 | |
| |---------------------------------->|
| | | |
| RTP Established Both Ways-Deposit Msg for B |
|<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->|
| | | |
| BYE F13 | | |
|---------------->| BYE F14 | |
| |---------------------------------->|
| | | |
| | OK F15 | |
| OK F16 |<----------------------------------|
|<----------------| | |
| | | |


Flow Id

INVITE F1 INVITE sip:UserB@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.



Campbell & Sparks Informational [Page 14]

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CSeq: 1
Contact: TheBigGuy Proxy-Authorization:Digest username="UserA",
realm="MCI WorldCom SIP",
nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="",
uri="sip:UserB@wcom.com", response=<
calculated hash goes here
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

/*Client for A prepares to receive data on port 49170
from the network. */

INVITE F2 INVITE sip:UserB1@somewhere.wcom.com SIP/2.0
Proxy->B1 Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

(100 Trying SIP/2.0 100
F3 Via: SIP/2.0/UDP here.com:5060
Proxy->A) From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0



Campbell & Sparks Informational [Page 15]

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180 Ringing SIP/2.0 180
F4 Via: SIP/2.0/UDP wcom.com:5060; branch=1
B1->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

180 Ringing SIP/2.0 180
F5 Via: SIP/2.0/UDP here.com:5060
Proxy->A From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

/* B1 rings for 9 seconds, this duration is
configurable parameter in the Proxy Server.
sends Cancel and proceeds down the list of routes
eventually hitting the voice mail URI for forward
answer */

CANCEL F6 CANCEL sip:UserB1@wcom.com SIP/2.0
Proxy->B1 Via: SIP/2.0/UDP wcom.com:5060; branch=1
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

200 OK F7 SIP/2.0 200
B1->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=1
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0


INVITE F8 INVITE sip:UserB-dep-fna@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060;branch=2
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1



Campbell & Sparks Informational [Page 16]

RFC 3087 SIP Service Control April 2001


Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

200 OK F9 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=2
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 1
Contact: TheLittleGuyVoiceMail fna@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000


200 OK F10 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 1
Contact: TheLittleGuyVoiceMail fna@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.



Campbell & Sparks Informational [Page 17]

RFC 3087 SIP Service Control April 2001


s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

ACK F11 ACK sip:UserB@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F12 ACK sip:UserB-dep-fna@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

/* RTP streams are established between A and B2.
system starts IVR dialog for message-deposit on no
answer for UserB */

/* User A Hangs Up with VM system. Alternatively,
VM system could initiate the BYE*/

BYE F13 BYE sip:UserB@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

BYE F14 BYE sip: UserB-dep-fna@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0



Campbell & Sparks Informational [Page 18]

RFC 3087 SIP Service Control April 2001


200 OK F15 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F16 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

4.2.2 Call to known subscriber forwarded on

User A attempts to call UserB, who is busy. The call is forwarded
UserB's mailbox, and the voice mail system plays UserB's
message for a busy. This flow assumes that "sip:UserB-dep
fb@vm.wcom.com" maps to UserB's mailbox and the behavior of "
message on busy."



























Campbell & Sparks Informational [Page 19]

RFC 3087 SIP Service Control April 2001


User A Proxy User B VM
| | | |
| INVITE F1 | | |
|---------------->| INVITE F2 | |
| |----------------->| |
| (100 Trying) F3 | | |
|<----------------| 486 Busy Here F4 | |
| |<-----------------| |
| | | |
| | ACK F5 | |
| |----------------->| |
| | | |
| | INVITE F6 |
| |---------------------------------->|
| | | |
| | 200 OK F7| |
| 200 OK F8 |<----------------------------------|
|<----------------| | |
| | | |
| ACK F9 | | |
|---------------->| ACK F10 | |
| |---------------------------------->|
| | | |
| RTP Established Both Ways-Deposit Msg for B |
|<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->|
| | | |
| BYE F11 | | |
|---------------->| BYE F12 | |
| |---------------------------------->|
| | | |
| | OK F13 | |
| OK F14 |<----------------------------------|
|<----------------| | |
| | | |

Flow Id

INVITE F1 INVITE sip:UserB@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Proxy-Authorization:Digest username="UserA",
realm="MCI WorldCom SIP",
nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="",
uri="sip:UserB@wcom.com", response=<



Campbell & Sparks Informational [Page 20]

RFC 3087 SIP Service Control April 2001


calculated hash goes here
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

/*Client for A prepares to receive data on port 49170
from the network. */

INVITE F2 INVITE sip:UserB1@somewhere.wcom.com SIP/2.0
Proxy->B1 Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

(100 Trying SIP/2.0 100
F3 Via: SIP/2.0/UDP here.com:5060
Proxy->A) From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

486 Busy SIP/2.0 486 Busy
Here F4 Via: SIP/2.0/UDP wcom.com:5060;branch=1
B1->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=123456



Campbell & Sparks Informational [Page 21]

RFC 3087 SIP Service Control April 2001


Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F5 ACK sip: UserB1@wcom.com SIP/2.0
Proxy->B Via: SIP/2.0/UDP wcom.com:5060; branch=1
From: TheBigGuy To: TheLittleGuy ;tag=123456
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

INVITE F6 INVITE sip:UserB-dep-fb@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060;branch=2
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

200 OK F7 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=2
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact: TheLittleGuyVoiceMail fb@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session



Campbell & Sparks Informational [Page 22]

RFC 3087 SIP Service Control April 2001


c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

200 OK F8 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact TheLittleGuyVoiceMail fb@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

ACK F9 ACK sip:UserB@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F10 ACK sip:UserB-dep-fb@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

/* RTP streams are established between A and B2.
system starts IVR dialog for message-deposit on
for UserB */





Campbell & Sparks Informational [Page 23]

RFC 3087 SIP Service Control April 2001


/* User A Hangs Up with VM system. Alternatively,
VM system could initiate the BYE*/

BYE F11 BYE sip:UserB@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

BYE F12 BYE sip: UserB-dep-fnb@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F13 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F14 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuy ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

4.2.3 Direct call to a subscriber's

User A calls UserB's mailbox directly. This flow assumes
"sip:UserB-dep@vm.wcom.com" maps to UserB's mailbox and the
of "generic message deposit








Campbell & Sparks Informational [Page 24]

RFC 3087 SIP Service Control April 2001


User A Proxy VM
| | |
| INVITE F1 | |
|------------------>| |
| | INVITE F2 |
| (100 Trying) F3 |---------------------->|
|<------------------| |
| | 200 OK F4 |
| 200 OK F5 |<----------------------|
|<------------------| |
| | |
| ACK F6 | |
|------------------>| ACK F7 |
| |---------------------->|
| | |
| RTP Both Ways - Deposit Msg for B |
|<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->|
| | |
| BYE F8 | |
|------------------>| BYE F9 |
| |---------------------->|
| | |
| | 200 OK F10 |
| |<----------------------|
| 200 OK F11 | |
|<------------------| |
| | |

Flow Id

INVITE F1 INVITE sip:UserB-VM@vm.wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuyVoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Proxy-Authorization:Digest username="UserA",
realm="MCI WorldCom SIP",
nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="",
uri="sip:UserB-VM@wcom.com", response=<
calculated hash goes here
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session



Campbell & Sparks Informational [Page 25]

RFC 3087 SIP Service Control April 2001


c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

/*Client for A prepares to receive data on port 49170
from the network. */

INVITE F2 INVITE sip:UserB-dep@vm.wcom.com SIP/2.0
Proxy->B1 Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuyVoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

(100 Trying SIP/2.0 100
F3 Via: SIP/2.0/UDP here.com:5060
Proxy->A) From: TheBigGuy To: TheLittleGuyVoiceMail Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

200 OK F4 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact: TheLittleGuyVoiceMail dep@vm.wcom.com
Content-Type: application/



Campbell & Sparks Informational [Page 26]

RFC 3087 SIP Service Control April 2001


Content-Length: <appropriate value
v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

200 OK F5 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact TheLittleGuyVoiceMail dep@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

ACK F6 ACK sip:UserB-VM@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F7 ACK sip:UserB-dep@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 1



Campbell & Sparks Informational [Page 27]

RFC 3087 SIP Service Control April 2001


Content-Length: 0
/* RTP streams are established between A and VM.
system starts IVR dialog for generic message-
for UserB */

/* User A Hangs Up with VM system. Alternatively,
VM system could initiate the BYE*/

BYE F8 BYE sip:UserB-VM@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

BYE F9 BYE sip: UserB-dep@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F10 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F11 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: TheLittleGuyVoiceMail VM@wcom.com>;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0





Campbell & Sparks Informational [Page 28]

RFC 3087 SIP Service Control April 2001


4.3 Message Retrieval

4.3.1 Call to retrieve messages believed to be from a known

Some user uses a SIP client on UserA's desk to call the voice
system to retrieve messages. The SIP client has authenticated
to the proxy using credentials assigned to the device. The proxy
make a weak assumption that the caller is the device owner. The
of "sip:UserA-retrieve@vm.wcom.com" maps to UserA's mailbox and
behavior of "retrieve messages after prompting for and
PIN." The VM System trusts the proxy, and will not accept calls
an untrusted source. The proxy will not allow direct calls
UserA-retrieve@vm.wcom.com. The proxy will forward calls placed
VoiceMail@wcom.com to UserA-retrieve@vm.wcom.com only for
placed from a client device assigned to UserA

User A Proxy VM
| | |
| INVITE F1 | |
|------------------>| |
| | INVITE F2 |
| (100 Trying) F3 |---------------------->|
|<------------------| |
| | 200 OK F4 |
| 200 OK F5 |<----------------------|
|<------------------| |
| | |
| ACK F6 | |
|------------------>| ACK F7 |
| |---------------------->|
| | |
| RTP Both Ways - VM prompts for
|<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->|
| | |
| BYE F8 | |
|------------------>| BYE F9 |
| |---------------------->|
| | |
| | 200 OK F10 |
| |<----------------------|
| 200 OK F11 | |
|<------------------| |
| | |








Campbell & Sparks Informational [Page 29]

RFC 3087 SIP Service Control April 2001


Flow Id

INVITE F1 INVITE sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Proxy-Authorization:Digest username="UserAPhone",
realm="MCI WorldCom SIP",
nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="",
uri="sip:VoiceMail@wcom.com", response=<
calculated hash goes here
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

/*Client for A prepares to receive data on port 49170
from the network. */

INVITE F2 INVITE sip:UserA-retrieve@vm.wcom.com SIP/2.0
Proxy->B1 Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000




Campbell & Sparks Informational [Page 30]

RFC 3087 SIP Service Control April 2001


(100 Trying SIP/2.0 100
F3 Via: SIP/2.0/UDP here.com:5060
Proxy->A) From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

200 OK F4 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact: VoiceMailSystem retrieve@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

200 OK F5 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact VoiceMailSystem retrieve@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000



Campbell & Sparks Informational [Page 31]

RFC 3087 SIP Service Control April 2001


ACK F6 ACK sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route:retrieve@vm.wcom.com
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F7 ACK sip:UserA-retrieve@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ; tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

/* RTP streams are established between A and VM.
determines that the call is likely from UserA,
starts a message retrieval session, prompting
PIN*/

/* User A Hangs Up with VM system. Alternatively,
VM system could initiate the BYE*/

BYE F8 BYE sip: VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route:retrieve@vm.wcom.com
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

BYE F9 BYE sip: UserA-retrieve@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F10 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy


Campbell & Sparks Informational [Page 32]

RFC 3087 SIP Service Control April 2001


To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F11 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

4.3.2 Call to retrieve messages from an authenticated

UserA to call the voice mail system to retrieve messages
Assumptions: The caller is authenticated using UserA's credentials
"sip:UserA-retrieve-auth@vm.wcom.com" maps to UserA's mailbox and
behavior of "retrieve messages." The voice mail service trusts
proxy not to forward any calls to that URI unless the call
authenticated to be from UserA

Given these assumptions, The VM service may choose not require a
for calls to this URI



























Campbell & Sparks Informational [Page 33]

RFC 3087 SIP Service Control April 2001


User A Proxy VM
| | |
| INVITE F1 | |
|------------------>| |
| | INVITE F2 |
| (100 Trying) F3 |---------------------->|
|<------------------| |
| | 200 OK F4 |
| 200 OK F5 |<----------------------|
|<------------------| |
| | |
| ACK F6 | |
|------------------>| ACK F7 |
| |---------------------->|
| | |
| RTP Both Ways - Deposit Msg for B |
|<-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m-m->|
| | |
| BYE F8 | |
|------------------>| BYE F9 |
| |---------------------->|
| | |
| | 200 OK F10 |
| |<----------------------|
| 200 OK F11 | |
|<------------------| |
| | |

Flow Id

INVITE F1 INVITE sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Proxy-Authorization:Digest username="UserA",
realm="MCI WorldCom SIP",
nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="",
uri="sip:VoiceMail@wcom.com", response=<
calculated hash goes here
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session



Campbell & Sparks Informational [Page 34]

RFC 3087 SIP Service Control April 2001


c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

/*Client for A prepares to receive data on port 49170
from the network. */

INVITE F2 INVITE sip:UserA-retrieve-auth@vm.wcom.com SIP/2.0
Proxy->B1 Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Contact: TheBigGuy Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserA 2890844526 2890844526 IN IP4 client.here.
s=Session
c=IN IP4 100.101.102.103
t=0 0
m=audio 49170 RTP/AVP 0
a=rtpmap:0 PCMU/8000

(100 Trying SIP/2.0 100
F3 Via: SIP/2.0/UDP here.com:5060
Proxy->A) From: TheBigGuy To: VoiceMail Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

200 OK F4 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060; branch=1
Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact: VoiceMailSystem retrieve
auth@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value



Campbell & Sparks Informational [Page 35]

RFC 3087 SIP Service Control April 2001


v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

200 OK F5 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
Record-Route: From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Contact VoiceMailSystem retrieve
auth@vm.wcom.com
Content-Type: application/
Content-Length: <appropriate value

v=0
o=UserB 2890844527 2890844527 IN IP4 vm.wcom.
s=Session
c=IN IP4 110.111.112.114
t=0 0
m=audio 3456 RTP/AVP 0
a=rtpmap:0 PCMU/8000

ACK F6 ACK sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route: retrieve-auth@vm.wcom.com
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0

ACK F7 ACK sip:UserA-retrieve-auth@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ; tag=3145678
Call-Id: 12345600@here.
CSeq: 1
Content-Length: 0






Campbell & Sparks Informational [Page 36]

RFC 3087 SIP Service Control April 2001


/* RTP streams are established between A and VM.
determines that the call is likely from UserA,
starts a message retrieval session. Since the
has already authenticated the identity of UserA,
VM does not need to prompt for PIN. */

/* User A Hangs Up with VM system. Alternatively,
VM system could initiate the BYE*/

BYE F8 BYE sip:VoiceMail@wcom.com SIP/2.0
A->Proxy Via: SIP/2.0/UDP here.com:5060
Route:retrieve-auth@vm.wcom.com
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

BYE F9 BYE sip: UserA-retrieve-auth@vm.wcom.com SIP/2.0
Proxy->VM Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F10 SIP/2.0 200
VM->Proxy Via: SIP/2.0/UDP wcom.com:5060
Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0

200 OK F11 SIP/2.0 200
Proxy->A Via: SIP/2.0/UDP here.com:5060
From: TheBigGuy To: VoiceMail ;tag=3145678
Call-Id: 12345600@here.
CSeq: 2
Content-Length: 0








Campbell & Sparks Informational [Page 37]

RFC 3087 SIP Service Control April 2001


5. Security

This document discusses a usage of SIP/2.0 as defined by RFC 2543[1].
It introduces no additions, modifications, or restrictions to
protocol defined therein. Any implementation of the concepts in
document is subject to the issues discussed there

6.

The authors would like to thank Chris Cunningham, Steve Donovan,
Johnston, Henry Sinnreich, Kevin Summers, John Truetken, and
Willis for their discussion of and contribution to this work



[1] Handley, M., Schulzrinne, H., Schooler, E. and J. Rosenberg
"SIP: Session Initiation Protocol", RFC 2543, March 1999.

Authors'

Ben

5100 Tennyson
Suite 1200
Plano, TX 75024

EMail: bcampbell@dynamicsoft.


Robert J.

5100 Tennyson
Suite 1200
Plano, TX 75024

EMail: rsparks@dynamicsoft.















Campbell & Sparks Informational [Page 38]

RFC 3087 SIP Service Control April 2001


Full Copyright

Copyright (C) The Internet Society (2001). All Rights Reserved

This document and translations of it may be copied and furnished
others, and derivative works that comment on or otherwise explain
or assist in its implementation may be prepared, copied,
and distributed, in whole or in part, without restriction of
kind, provided that the above copyright notice and this paragraph
included on all such copies and derivative works. However,
document itself may not be modified in any way, such as by
the copyright notice or references to the Internet Society or
Internet organizations, except as needed for the purpose
developing Internet standards in which case the procedures
copyrights defined in the Internet Standards process must
followed, or as required to translate it into languages other
English

The limited permissions granted above are perpetual and will not
revoked by the Internet Society or its successors or assigns

This document and the information contained herein is provided on
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED,
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE



Funding for the RFC Editor function is currently provided by
Internet Society



















Campbell & Sparks Informational [Page 39]

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this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.



RFC documents can be found at I.E.T.F.



Relevance System Copyright © 2002 Spectrum WorldResearch
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collaboration of BobX

---