draft-ietf-sipcore-originating-cdiv-parameter-02.txt   draft-ietf-sipcore-originating-cdiv-parameter-03.txt 
SIPCORE Working Group M. Mohali SIPCORE Working Group M. Mohali
Internet-Draft Orange Internet-Draft Orange
Updates: 5502 (if approved) May 22, 2018 Updates: 5502 (if approved) August 27, 2018
Intended status: Informational Intended status: Informational
Expires: November 23, 2018 Expires: February 28, 2019
A P-Served-User Header Field Parameter for Originating CDIV session case A P-Served-User Header Field Parameter for Originating CDIV session case
in Session Initiation Protocol (SIP) in Session Initiation Protocol (SIP)
draft-ietf-sipcore-originating-cdiv-parameter-02 draft-ietf-sipcore-originating-cdiv-parameter-03
Abstract Abstract
The P-Served-User header field RFC5502 is used to convey the identity The P-Served-User header field is used to convey the identity of the
of the served user and the session case that applies to this served user and the session case that applies to this particular
particular communication session and application invocation. This communication session and application invocation. This document
document updated RFC5502 by defining a new P-Served-User header field updates RFC5502 by defining a new P-Served-User header field
parameter, "orig-cdiv". The parameter conveys the session case used parameter, "orig-cdiv". The parameter conveys the session case used
by a proxy when handling an originating session after Call Diversion by a proxy when handling an originating session after Call Diversion
(CDIV) services has been invoked for the served user. This document (CDIV) services have been invoked for the served user. This document
also fixes the ABNF in RFC5502 and provides more guidance for using also fixes the ABNF in RFC 5502 and provides more guidance for using
the P-Served-User header field in IP networks. the P-Served-User header field in IP networks.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on November 23, 2018. This Internet-Draft will expire on February 28, 2019.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Basic Use Case . . . . . . . . . . . . . . . . . . . . . 3 1.2. Basic Use Case . . . . . . . . . . . . . . . . . . . . . 3
1.3. Problem Statement . . . . . . . . . . . . . . . . . . . . 4 1.3. Problem Statement . . . . . . . . . . . . . . . . . . . . 4
2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
3. Proxy behavior and parameter handling . . . . . . . . . . . . 4 3. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Clarification of RFC5502 procedures . . . . . . . . . . . . . 5 4. Proxy behavior and parameter handling . . . . . . . . . . . . 5
5. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Clarification of RFC5502 procedures . . . . . . . . . . . . . 6
5.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. ABNF . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6.2. ABNF . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Call Flow Examples . . . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7.1. Call diversion case . . . . . . . . . . . . . . . . . . . 8 8. Call Flow Examples . . . . . . . . . . . . . . . . . . . . . 8
7.2. Call diversion and privacy . . . . . . . . . . . . . . . 10 8.1. Call diversion case . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 8.2. Call diversion and privacy . . . . . . . . . . . . . . . 10
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
10.1. Normative References . . . . . . . . . . . . . . . . . . 12 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
10.2. Informative References . . . . . . . . . . . . . . . . . 12 11.1. Normative References . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13 11.2. Informative References . . . . . . . . . . . . . . . . . 13
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction 1. Introduction
1.1. General 1.1. General
The P-Served-User header field [RFC5502] was defined based on a The P-Served-User header field [RFC5502] was defined based on a
requirement from 3rd Generation Partnership Project (3GPP) IMS (IP requirement from 3rd Generation Partnership Project (3GPP) IMS (IP
Multimedia Subsystem) in order to convey the identity of the served Multimedia Subsystem) in order to convey the identity of the served
user, his/her registration state and the session case between an user, his/her registration state and the session case between an
S-CSCF (Serving Call Session Control Function) and an AS (Application S-CSCF (Serving Call Session Control Function) and an AS (Application
Server) on the ISC (IMS Service Control) interface. For more Server) on the ISC (IMS Service Control) interface. For more
information on the IMS, a detailed description can be found in information on session cases and the IMS, a detailed description can
[TS.3GPP.24.229]. be found in [TS.3GPP.24.229].
[RFC5502] defines the originating and terminating session cases for a [RFC5502] defines the originating and terminating session cases for a
registered or unregistered user. This document extends the P-Served- registered or unregistered user. This document extends the P-Served-
User header field to include the session case for a forwarded leg User header field to include the session case for a forwarded leg
when a call diversion service (CDIV) has been invoked and if an when a call diversion service (CDIV) has been invoked and if an
originating service of the diverting user has to be triggered. originating service of the diverting user has to be triggered.
The sessioncase-param parameter of the P-Served-User header field is The sessioncase-param parameter of the P-Served-User header field is
extended with the "orig-cdiv" parameter for this "originating after extended with the "orig-cdiv" parameter for this "originating after
CDIV" session case. CDIV" session case.
The following section defines usage of the "orig-cdiv" parameter of The following section defines usage of the "orig-cdiv" parameter of
P-Served-User header field, Section 2 discusses the applicability and P-Served-User header field, Section 3 discusses the applicability and
scope of this new header field parameter, and Section 3 specifies the scope of this new header field parameter, and Section 4 specifies the
proxy behavior for handling the new header field parameter. proxy behavior for handling the new header field parameter.
Section 4 clarifies some of the [RFC5502] procedures, Section 5 Section 5 clarifies some of the [RFC5502] procedures, Section 6
describes the extended syntax and correct the syntax of [RFC5502], describes the extended syntax and corrects the syntax of [RFC5502],
Section 6 registers the P-Served-User header field parameters with Section 7 registers the P-Served-User header field parameters with
IANA, Section 7 gives some examples and Section 8 discusses the IANA, Section 8 gives some examples, and Section 9 discusses the
security properties of the environment where this new header field security properties of the environment where this new header field
parameter is intended to be used. parameter is intended to be used.
1.2. Basic Use Case 1.2. Basic Use Case
In the 3GPP IMS (IP Multimedia Subsystem), the S-CSCF (Serving CSCF) In the 3GPP IMS (IP Multimedia Subsystem), the S-CSCF (Serving CSCF)
is a SIP proxy that serves as a registrar and handles originating and is a SIP proxy that serves as a registrar and handles originating and
terminating session states for users allocated to it. This means terminating session states for users allocated to it. This means
that any call that is originated by a specific user or any call that that any call that is originated by a specific user or any call that
is terminated to that specific user will pass through the S-CSCF that is terminated to that specific user will pass through the S-CSCF that
is allocated to that user. is allocated to that user.
At the moment that an S-CSCF is allocated for a specific user, the At the moment that an S-CSCF is allocated for a specific user, the
user profile is downloaded from the HSS (Home Subscriber Server) to user profile is downloaded from the HSS (Home Subscriber Server) to
this S-CSCF, see [TS.3GPP.29.228]. The user profile contains the this S-CSCF, see [TS.3GPP.29.228]. The user profile contains the
list of actions to be taken by the S-CSCF for the served user list of actions to be taken by the S-CSCF for the served user
depending on the session direction (originating or terminating) and depending on the session direction (originating or terminating) and
the user state (registered or not) in the IMS network. With this the user state (registered or not) in the IMS network. With this
user profile, the S-CSCF determines the current case and apply the user profile, the S-CSCF determines the current case and applies the
corresponding actions such as forward the request to an AS. At its corresponding actions such as forwarding the request to an AS. The
turn, the AS has to go through a similar process of determining who AS then goes through a similar process of determining who is the
is the current served user, what is his/her "registration state" and current served user, what is his/her "registration state", and what
on which "session case" is the session. [RFC5502] defines all those is the "session case" of the session. [RFC5502] defines all those
parameters and in particular the originating and terminating session parameters and in particular the originating and terminating session
cases. cases.
In basic call scenarios, the is no particular issue for the S-CSCF In basic call scenarios, there is no particular issue for the S-CSCF
and AS to know which scenario needs to be realized but in case of and AS to know which scenario needs to be realized, but in case of
call diversion services for which the session is re-targeted, the call diversion services for which the session is re-targeted, the
session cases defined in [RFC5502] poses some limitations as session cases defined in [RFC5502] pose some limitations as described
described in the following section. in the following section.
1.3. Problem Statement 1.3. Problem Statement
In case of a call diversion service, the received request is first In the case of a call diversion service, the received request is
considered as a terminating session case and the terminating filter first considered as a terminating session case, and the terminating
criteria configured in the S-CSCF are performed. Receiving the call filter criteria configured in the S-CSCF are performed. When the AS
initiation request, the AS is able to determine the served user and receives the call initiation request, the AS is able to determine the
the session case (here "term") from the received P-Served-User header served user and the session case (here "term") from the received P-
field content and to execute terminating services. When the call Served-User header field content and to execute terminating services.
diversion service is executed (as a terminating service), the AS When the call diversion service is executed (as a terminating
changes the target (Request-URI) of the session and a new call leg is service), the AS changes the target (Request-URI) of the session and
created. This new call leg could be considered as an originating a new call leg is created. This new call leg could be considered as
call leg from the diverting user but this is not the case. Indeed, an originating call leg from the diverting user but this is not the
the originating user remains the same and some of the diverting case. Indeed, the originating user remains the same, and some of the
user's originating services should not be triggered as if it was an diverting user's originating services should not be triggered as if
originating call. For instance, the originating user identity should it was an originating call. For instance, the originating user
not be restricted because the diverting user has a privacy service identity should not be restricted because the diverting user has a
for his/her own identity. The privacy of the diverting user should privacy service for his/her own identity. The privacy of the
apply to information related to this user (eg. in the History-Info diverting user should apply to information related to this user (eg.
header field). In the same manner, some specific services will need in the History-Info header field). In the same manner, some specific
to be specifically triggered on the outgoing leg after a call services will need to be specifically triggered on the outgoing leg
diversion. Without a dedicated session case for originating after after a call diversion. Without a dedicated session case for
CDIV, there is no possiblity for a proxy to trigger an originating originating after CDIV, the S-CSCF cannot trigger an originating
service for the diverting user or for an AS to execute the procedures service for the diverting user, nor can an AS execute the procedures
for this particular session case. for this particular session case.
For this use case, this document creates a new parameter for the For this use case, this document creates a new parameter for the
originating after CDIV session case to be embedded in the P-Served- originating after CDIV session case to be embedded in the P-Served-
User header field. User header field.
2. Applicability 2. Conventions and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Applicability
The use of the P-Served-User header field extensions is only The use of the P-Served-User header field extensions is only
applicable inside a Trust Domain for P-Served-User header field. applicable inside a Trust Domain [RFC3324] for P-Served-User header
Nodes in such a Trust Domain explicitly trust each other to convey field. Nodes in such a Trust Domain explicitly trust each other to
the served user and to be responsible for withholding that convey the served user and to be responsible for withholding that
information outside of the Trust Domain. The means by which the information outside of the Trust Domain. The means by which the
network determines the served user and the policies that are executed network determines the served user and the policies that are executed
for a specific served user is outside the scope of this document. for a specific served user is outside the scope of this document.
3. Proxy behavior and parameter handling 4. Proxy behavior and parameter handling
The following section illustrates how this header field parameter can The following section illustrates how this header field parameter can
be used in a 3GPP network. be used in a 3GPP network.
For a terminating call, the following steps will be followed: For a terminating call, the following steps will be followed:
1. The S-CSCF receives the initial INVITE request for a terminating 1. The S-CSCF receives the initial INVITE request for a terminating
call and determines that the session case is for a terminating call and determines that the session case is for a terminating
user as described in [RFC5502]; user as described in [RFC5502];
2. The S-CSCF determines who is the served user by looking at the 2. The S-CSCF determines who is the served user by looking at the
Request-URI and saves the current Request-URI; Request-URI and saves the current Request-URI;
3. The S-CSCF starts the analysis of filter criteria and triggers 3. The S-CSCF analyzes the filter criteria. It then sends to the AS
the served user AS for the terminating services to be executed by of the served user an INVITE that includes the P-Served-User
including in the INVITE request the P-Served-User header field header field with the "sescase" parameter set to "term" and the
with the "sescase" parameter set to "term" and the regstate to "regstate" set to the corresponding value in order to trigger
the corresponding value; execution of terminating services;
4. Based on some criteria, the AS concludes that the request has to 4. Based on some criteria, the AS concludes that the request has to
be diverted to another target user or application. The received be diverted to another target user or application. The AS
Request-URI is then replaced with the new diverted-to address and replaces the received Request-URI with the new diverted-to
the AS stores the successive Request-URI(s) values by adding one address and the AS stores the successive Request-URI(s) values by
or two History-Info header field entry(ies) [RFC7044] in the adding one or two History-Info header field entry(ies) [RFC7044]
outgoing INVITE. In the History-Info header field, the served in the outgoing INVITE. In the History-Info header field, the
user address is tagged using the mp-param header field parameter served user address is tagged using the mp-param header field
added in entry associated to the diverted-to address created. parameter added in entry associated to the diverted-to address
The AS forwards the INVITE request back to the S-CSCF; created. The AS forwards the INVITE request back to the S-CSCF;
5. When receiving back the INVITE request, the S-CSCF can see that 5. When receiving back the INVITE request, the S-CSCF can see that
the topmost Route header field contains its own hostname but the the topmost Route header field contains its own hostname but the
Request-URI does not match the saved Request-URI. In this case, Request-URI does not match the saved Request-URI. In this case,
the S-CSCF updates the P-Served-User header field content by the S-CSCF updates the P-Served-User header field content by
replacing the "sescase" parameter by the "orig-cdiv" parameter. replacing the "sescase" parameter with the "orig-cdiv" parameter.
The P-Served-User header field value remains unchanged; The P-Served-User header field value remains unchanged;
6. The S-CSCF forwards the INVITE request over to an AS that hosts 6. The S-CSCF forwards the INVITE request to an AS that hosts the
the originating services of the served user (diverting user) that originating services of the served user (diverting user) that
specifically need to be executed on the forwarded leg after a specifically need to be executed on the forwarded leg after a
call diversion service; call diversion service;
7. When the AS receives the INVITE request, it determines that the 7. When the AS receives the INVITE request, it determines that the
session case is for "orig-cdiv" session case and will perform the session case is for "orig-cdiv" session case and performs the
originating services to be executed after retargeting for the originating services to be executed after retargeting for the
diverting user (i.e. served user). diverting user (i.e. served user).
4. Clarification of RFC5502 procedures 5. Clarification of RFC5502 procedures
This document provides the following guidance that reminds and This document provides the following guidance for the handling of the
clarifies the P-Served-User header field handling that are missing in P-Served-User header field that are missing in [RFC5502]:
[RFC5502]:
o This header MUST NOT be repeated within a request for a particular o The P-Served-User header field MUST NOT be repeated within a
session at a particular time for the reason that session cases are request for a particular session at a particular time for the
mutually exclusive. This document updates [RFC5502] to clearly reason that session cases are mutually exclusive. This document
state that P-Served-User header field MUST NOT contain different updates [RFC5502] to clearly state that the P-Served-User header
values either comma-separated or header-separated. This documents field MUST NOT contain different values either comma-separated or
also updates the syntax of the header from [RFC5502] to reflect header-separated. This documents also updates the syntax of the
this uniqueness of parameters values. header from [RFC5502] to reflect this uniqueness of parameters
values.
o Whether the "regstate" parameter is removed or not by the S-CSCF o Whether the S-CSCF removes the "regstate" parameter when it
when processing the orginating after CDIV session case is out of processes the orig-cdiv session case is out of the scope of this
the scope of this document. In one hand, it can either be document. The S-CSCF could store the previous regstate value and
considered that the S-CSCF is able to store the previous regstate that the same value applies, or the "regstate" may not be relevant
value and that the same value applies or that the "regstate" is after a diverting service, or the regstate could be combined with
not relevant after a diverting service. On the other hand, the the orig-cdiv session case to provide different services if the
regstate can be combined to the orig-cdiv session case to provide served user is registered or unregistered. These choices are
different services if the served user is registered or implementation dependent.
unregistered. These choices are implementation dependent.
5. Syntax 6. Syntax
5.1. General 6.1. General
[RFC5502] defines the P-Served-User header field with the [RFC5502] defines the P-Served-User header field with the
sessioncase-param parameter "sescase" which is specified as having sessioncase-param parameter "sescase" which is specified as having
"orig" and "term" predefined values. This document defines an "orig" and "term" predefined values. This document defines an
additional parameter for the sessioncase-param: "orig-cdiv". additional parameter for the sessioncase-param: "orig-cdiv".
Because this document extends the existing sessioncase-param Because this document extends the existing sessioncase-param
parameter in a special way and that it has been identified errors in parameter, and because errors have been identified in the syntax,
the syntax of the P-Served-User header field [RFC5502], this document this document corrects and extends the P-Served-User header field.
corrects and extends the header at the same time.
The extension of the sessioncase-param parameter to add the "orig- The extension of the sessioncase-param parameter to add the "orig-
cdiv" session case is done in a way to fit the parameter format cdiv" session case is done in a way to fit the parameter format
introduced in release 11 of the 3GPP [TS.3GPP.24.229] and keep a introduced in Release 11 of the 3GPP [TS.3GPP.24.229] and to maintain
backward compatibility. a backward compatibility.
"EQUAL", "HCOLON", "SEMI", "name-addr", "addr-spec", and "generic- "EQUAL", "HCOLON", "SEMI", "name-addr", "addr-spec", and "generic-
param" are defined in [RFC3261]. param" are defined in [RFC3261].
5.2. ABNF 6.2. ABNF
The augmented Backus-Naur Form (ABNF) [RFC5234] syntax of the P- The augmented Backus-Naur Form (ABNF) [RFC5234] syntax of the P-
Served-User header field is described in [RFC5502]. Served-User header field is described in [RFC5502].
This document updates [RFC5502] to correct the P-Served-User header This document updates [RFC5502] to correct the P-Served-User header
field ABNF syntax and extend it as following: field ABNF syntax and extend it as following:
P-Served-User = "P-Served-User" HCOLON PServedUser-value P-Served-User = "P-Served-User" HCOLON PServedUser-value
*(SEMI served-user-param) *(SEMI served-user-param)
served-user-param = sessioncase-param served-user-param = sessioncase-param
skipping to change at page 7, line 23 skipping to change at page 7, line 39
orig-cdiv = "orig-cdiv" orig-cdiv = "orig-cdiv"
Examples of possible P-Served-User header field: Examples of possible P-Served-User header field:
P-Served-User: <sip:user@example.com>; orig-cdiv; regstate=reg P-Served-User: <sip:user@example.com>; orig-cdiv; regstate=reg
or or
P-Served-User: <sip:user@example.com>; orig-cdiv P-Served-User: <sip:user@example.com>; orig-cdiv
or or
P-Served-User: <sip:user@example.com>; sescase=term; regstate=unreg P-Served-User: <sip:user@example.com>; sescase=term; regstate=unreg
6. IANA Considerations This document allows choosing between addr-spec and name-addr when
constructing the header field value. As specified in RFC 8217, the
"addr-spec" form MUST NOT be used if its value would contain a comma,
semicolon, or question mark [RFC8217].
7. IANA Considerations
The syntax of the P-Served-User header field [RFC5502] is updated in The syntax of the P-Served-User header field [RFC5502] is updated in
Section 4 of this document. Section 4 of this document.
This document requests IANA to update the existing row for the P- This document requests IANA to update the existing row for the P-
Served-User header field in the "Header Fields" sub-registry: Served-User header field in the "Header Fields" sub-registry within
the "Session Initiation Protocol (SIP) Parameters" registry:
Header Name Compact Form Reference Header Name Compact Form Reference
------------- ------------ ---------------- ------------- ------------ ----------------
P-Served-User none [RFC5502][RFCXXXX] P-Served-User none [RFC5502][RFCXXXX]
Note to RFC Editor: Please replace XXXX with the RFC number of this Note to RFC Editor: Please replace XXXX with the RFC number of this
document. document.
This document requests IANA to add new rows for the P-Served-User This document requests IANA to add new rows for the P-Served-User
header field parameters in the "Header Field Parameters and Parameter header field parameters in the "Header Field Parameters and Parameter
Values" sub-registry as per the registry created by [RFC3968]: Values" sub-registry within the "Session Initiation Protocol (SIP)
Parameters" registry: as per the registry created by [RFC3968]:
Header Field Parameter Name Predefined Values Reference Header Field Parameter Name Predefined Values Reference
-------------- ---------------- ----------------- ----------------- -------------- ---------------- ----------------- -----------------
P-Served-User sescase Yes [RFC5502][RFCXXXX] P-Served-User sescase Yes [RFC5502][RFCXXXX]
P-Served-User regstate Yes [RFC5502][RFCXXXX] P-Served-User regstate Yes [RFC5502][RFCXXXX]
P-Served-User orig-cdiv No [RFCXXXX] P-Served-User orig-cdiv No [RFCXXXX]
Note to RFC Editor: Please replace XXXX with the RFC number of this Note to RFC Editor: Please replace XXXX with the RFC number of this
document. document.
7. Call Flow Examples 8. Call Flow Examples
7.1. Call diversion case 8.1. Call diversion case
The following call flow shows a session establishement for Alice The following call flow shows a session establishment when Alice
calls Bob which has a call diversion when busy towards Carol. calls Bob, who has a call diversion service that diverts to Carol
when Bob is busy.
proxy server UA proxy server UA
Alice Bob's...S-CSCF-B..........AS-B.............Bob Carol Alice Bob's...S-CSCF-B..........AS-B.............Bob Carol
| | | | | | | | | |
| INVITE F1 | | | | | INVITE F1 | | | |
|--------------->| INVITE F2 | | | |--------------->| INVITE F2 | | |
| |--------------->| | | | |--------------->| | |
| | INVITE F3 | | | | | INVITE F3 | | |
| |<---------------| INVITE F4 | | | |<---------------| INVITE F4 | |
| |-------------------------------->| | | |-------------------------------->| |
skipping to change at page 8, line 49 skipping to change at page 9, line 19
| |<---------------| INVITE F10 | | |<---------------| INVITE F10 |
| |------------------------------------------------->| | |------------------------------------------------->|
| | | | | | | | | |
| | | | 180 F11 | | | | | 180 F11 |
| | | 180 F12 |<---------------| | | | 180 F12 |<---------------|
| | 180 F13 |<---------------| | | | 180 F13 |<---------------| |
| 180 F14 |<---------------| | | | 180 F14 |<---------------| | |
|<---------------| | | | |<---------------| | | |
| | | | | | | | | |
[Alice calls Bob]
F1 INVITE Alice -> S-CSCF-B F1 INVITE Alice -> S-CSCF-B
INVITE sip:bob@example.com SIP/2.0 INVITE sip:bob@example.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
F2 INVITE S-CSCF-B -> AS-B F2 INVITE S-CSCF-B -> AS-B
INVITE sip:bob@example.com SIP/2.0 INVITE sip:bob@example.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; term; regstate=reg P-Served-User: <sip:bob@example.com>; term; regstate=reg
skipping to change at page 9, line 24 skipping to change at page 9, line 44
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; term; regstate=reg P-Served-User: <sip:bob@example.com>; term; regstate=reg
F4 INVITE S-CSCF-B -> Bob F4 INVITE S-CSCF-B -> Bob
INVITE sip:bob@192.0.2.4 SIP/2.0 INVITE sip:bob@192.0.2.4 SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; term; regstate=reg P-Served-User: <sip:bob@example.com>; term; regstate=reg
[Bob is busy. His call diversion when busy is invoked towards Carol]
F5-F6 486 BUSY Bob -> S-CSCF-B -> AS-B F5-F6 486 BUSY Bob -> S-CSCF-B -> AS-B
486 BUSY 486 BUSY
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com>;tag=es43sd To: Bob <sip:bob@example.com>;tag=es43sd
[Alice's call is diverted to Carol]
F7 INVITE AS-B -> S-CSCF-B F7 INVITE AS-B -> S-CSCF-B
INVITE sip:Carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; term; regstate=reg P-Served-User: <sip:bob@example.com>; term; regstate=reg
[Forwarded leg to Carol is identified as an originating call after
diversion that should not trigger all Bob's originating services]
F8 INVITE S-CSCF-B -> AS-B F8 INVITE S-CSCF-B -> AS-B
INVITE sip:Carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg
F9 INVITE AS-B -> S-CSCF-B F9 INVITE AS-B -> S-CSCF-B
INVITE sip:carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg
skipping to change at page 10, line 4 skipping to change at page 10, line 29
F9 INVITE AS-B -> S-CSCF-B F9 INVITE AS-B -> S-CSCF-B
INVITE sip:carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg
F10 INVITE S-CSCF-B -> Carol F10 INVITE S-CSCF-B -> Carol
INVITE sip:carol@192.0.2.7 SIP/2.0 INVITE sip:carol@192.0.2.7 SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
Figure 1: P-Served-User during call diversion service Figure 1: P-Served-User during call diversion service
7.2. Call diversion and privacy 8.2. Call diversion and privacy
The following call flow shows a call diversion use case for which The following call flow shows a call diversion use case for which
Alice has no identity restriction service and Bob has an Alice has no identity restriction service and Bob has an
unconditional call diversion service towards Carol and an identity unconditional call diversion service towards Carol and an identity
presentation restriction service. presentation restriction service.
proxy server UA proxy server UA
Alice Bob's...S-CSCF-B..........AS-B.............Bob Carol Alice Bob's...S-CSCF-B..........AS-B.............Bob Carol
| | | | | | | | | |
| INVITE F1 | | | | | INVITE F1 | | | |
skipping to change at page 10, line 34 skipping to change at page 11, line 13
| |<---------------| INVITE F6 | | | |<---------------| INVITE F6 | |
| |------------------------------------------------->| | |------------------------------------------------->|
| | | | | | | | | |
| | | | 180 F7 | | | | | 180 F7 |
| | | 180 F8 |<---------------| | | | 180 F8 |<---------------|
| | 180 F9 |<---------------| | | | 180 F9 |<---------------| |
| 180 F10 |<---------------| | | | 180 F10 |<---------------| | |
|<---------------| | | | |<---------------| | | |
| | | | | | | | | |
[Alice calls Bob]
F1 INVITE Alice -> S-CSCF-B F1 INVITE Alice -> S-CSCF-B
INVITE sip:bob@example.com SIP/2.0 INVITE sip:bob@example.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
Supported: histinfo Supported: histinfo
F2 INVITE S-CSCF-B -> AS-B F2 INVITE S-CSCF-B -> AS-B
INVITE sip:bob@example.com SIP/2.0 INVITE sip:bob@example.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Bob <sip:bob@example.com> To: Bob <sip:bob@example.com>
P-Served-User: <sip:bob@example.com>; term; regstate=reg P-Served-User: <sip:bob@example.com>; term; regstate=reg
[Bob's unconditional call diversion to Carol is triggered]
F3 INVITE AS-B -> S-CSCF-B F3 INVITE AS-B -> S-CSCF-B
INVITE sip:carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Carol <sip:carol@domainc.com> To: Carol <sip:carol@domainc.com>
P-Served-User: <sip:bob@example.com>; term; regstate=reg P-Served-User: <sip:bob@example.com>; term; regstate=reg
History-Info: History-Info:
<sip:bob@example.com>;index=1, <sip:bob@example.com>;index=1,
<sip:carol@domainc.com;cause=302>;index=1.1;mp=1 <sip:carol@domainc.com;cause=302>;index=1.1;mp=1
[Alice's call is diverted to Carol]
F4 INVITE S-CSCF-B -> AS-B F4 INVITE S-CSCF-B -> AS-B
INVITE sip:carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Carol <sip:carol@domainc.com> To: Carol <sip:carol@domainc.com>
P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg
History-Info: History-Info:
<sip:bob@example.com>;index=1, <sip:bob@example.com>;index=1,
<sip:carol@domainc.com;cause=302>;index=1.1;mp=1 <sip:carol@domainc.com;cause=302>;index=1.1;mp=1
F5 INVITE AS-B -> S-CSCF-B F5 INVITE AS-B -> S-CSCF-B
INVITE sip:carol@domainc.com SIP/2.0 INVITE sip:carol@domainc.com SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Carol <sip:carol@domainc.com> To: Carol <sip:carol@domainc.com>
P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg P-Served-User: <sip:bob@example.com>; orig-cdiv; regstate=reg
History-Info: History-Info:
<sip:bob@example.com?privacy=history>;index=1, <sip:bob@example.com?privacy=history>;index=1,
<sip:carol@domainc.com;cause=302>;index=1.1;mp=1 <sip:carol@domainc.com;cause=302>;index=1.1;mp=1
[Forwarded leg to Carol is identified as an originating call after
diversion that allows to apply Bob's privacy request to his identity
within the Histroy-Info header field]
F6 INVITE S-CSCF-B -> Carol F6 INVITE S-CSCF-B -> Carol
INVITE sip:carol@192.0.2.7 SIP/2.0 INVITE sip:carol@192.0.2.7 SIP/2.0
From: Alice <sip:alice@domaina.com>;tag=1928301774 From: Alice <sip:alice@domaina.com>;tag=1928301774
To: Carol <sip:carol@domainc.com> To: Carol <sip:carol@domainc.com>
History-Info: History-Info:
<sip:bob@example.com?privacy=history>;index=1, <sip:bob@example.com?privacy=history>;index=1,
<sip:carol@domainc.com;cause=302>;index=1.1;mp=1 <sip:carol@domainc.com;cause=302>;index=1.1;mp=1
<sip:carol@192.0.2.7>;index=1.1.1;rc=1.1 <sip:carol@192.0.2.7>;index=1.1.1;rc=1.1
Figure 2: P-Served-User when privacy requested Figure 2: P-Served-User when privacy requested
8. Security Considerations 9. Security Considerations
The security considerations in [RFC5502] apply. The security considerations in [RFC5502] apply.
As the "orig-cdiv" parameter of P-Served-User header field can be As the "orig-cdiv" parameter of P-Served-User header field can be
used to trigger applications, it is important to ensure that the used to trigger applications, it is important to ensure that the
parameter has not been added to the SIP message by an unauthorized parameter has not been added to the SIP message by an unauthorized
SIP entity. SIP entity.
9. Acknowledgments 10. Acknowledgments
The author wishes to thank the 3GPP community for providing guidance, The author wishes to thank the 3GPP community for providing guidance,
input, and comments on the document. Thanks to Dale Worley for his input, and comments on the document. Thanks to Dale Worley and Jean
careful review of the document and to Paul Kyzivat. A special thanks Mahoney for their careful review of the document. Thanks to Paul
to Christer Holmberg. Kyzivat and Adam Roach. A special thanks to Christer Holmberg.
10. References 11. References
10.1. Normative References 11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3324] Watson, M., "Short Term Requirements for Network Asserted
Identity", RFC 3324, DOI 10.17487/RFC3324, November 2002,
<https://www.rfc-editor.org/info/rfc3324>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, DOI 10.17487/RFC3261, June 2002,
<https://www.rfc-editor.org/info/rfc3261>. <https://www.rfc-editor.org/info/rfc3261>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8217] Sparks, R., "Clarifications for When to Use the name-addr
Production in SIP Messages", RFC 8217,
DOI 10.17487/RFC8217, August 2017,
<https://www.rfc-editor.org/info/rfc8217>.
[RFC3968] Camarillo, G., "The Internet Assigned Number Authority [RFC3968] Camarillo, G., "The Internet Assigned Number Authority
(IANA) Header Field Parameter Registry for the Session (IANA) Header Field Parameter Registry for the Session
Initiation Protocol (SIP)", BCP 98, RFC 3968, Initiation Protocol (SIP)", BCP 98, RFC 3968,
DOI 10.17487/RFC3968, December 2004, DOI 10.17487/RFC3968, December 2004,
<https://www.rfc-editor.org/info/rfc3968>. <https://www.rfc-editor.org/info/rfc3968>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008, DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>. <https://www.rfc-editor.org/info/rfc5234>.
[RFC7044] Barnes, M., Audet, F., Schubert, S., van Elburg, J., and [RFC7044] Barnes, M., Audet, F., Schubert, S., van Elburg, J., and
C. Holmberg, "An Extension to the Session Initiation C. Holmberg, "An Extension to the Session Initiation
Protocol (SIP) for Request History Information", RFC 7044, Protocol (SIP) for Request History Information", RFC 7044,
DOI 10.17487/RFC7044, February 2014, DOI 10.17487/RFC7044, February 2014,
<https://www.rfc-editor.org/info/rfc7044>. <https://www.rfc-editor.org/info/rfc7044>.
10.2. Informative References
[RFC5502] van Elburg, J., "The SIP P-Served-User Private-Header [RFC5502] van Elburg, J., "The SIP P-Served-User Private-Header
(P-Header) for the 3GPP IP Multimedia (IM) Core Network (P-Header) for the 3GPP IP Multimedia (IM) Core Network
(CN) Subsystem", RFC 5502, DOI 10.17487/RFC5502, April (CN) Subsystem", RFC 5502, DOI 10.17487/RFC5502, April
2009, <https://www.rfc-editor.org/info/rfc5502>. 2009, <https://www.rfc-editor.org/info/rfc5502>.
11.2. Informative References
[TS.3GPP.24.229] [TS.3GPP.24.229]
3GPP, "IP multimedia call control protocol based on 3GPP, "IP multimedia call control protocol based on
Session Initiation Protocol (SIP) and Session Description Session Initiation Protocol (SIP) and Session Description
Protocol (SDP);Stage 3", 3GPP TS 24.229 v11. Protocol (SDP);Stage 3", 3GPP TS 24.229 v11.
[TS.3GPP.29.228] [TS.3GPP.29.228]
3GPP, "IP Multimedia (IM) Subsystem Cx and Dx interfaces; 3GPP, "IP Multimedia (IM) Subsystem Cx and Dx interfaces;
Signalling flows and message contents", 3GPP TS 29.228 Signalling flows and message contents", 3GPP TS 29.228
v11. v11.
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