Private Header (P-Header) Extension to the Session Initiation Protocol (SIP) for Authorization of Early Media
RFC 5009
| Document | Type |
RFC - Informational
(September 2007; No errata)
Was draft-ejzak-sipping-p-em-auth (individual in gen area)
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5009 (Informational) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Jon Peterson | ||
| Send notices to | (None) | ||
Network Working Group R. Ejzak
Request for Comments: 5009 Alcatel-Lucent
Category: Informational September 2007
Private Header (P-Header) Extension to
the Session Initiation Protocol (SIP) for Authorization of Early Media
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Abstract
This document describes a private Session Initiation Protocol (SIP)
header field (P-header) to be used by the European Telecommunications
Standards Institute (ETSI) Telecommunications and Internet-converged
Services and Protocols for Advanced Networks (TISPAN) for the purpose
of authorizing early media flows in Third Generation Partnership
Project (3GPP) IP Multimedia Subsystems (IMS). This header field is
useful in any SIP network that is interconnected with other SIP
networks and needs to control the flow of media in the early dialog
state.
Ejzak Informational [Page 1]
RFC 5009 P-Early-Media Header September 2007
Table of Contents
1. Introduction ....................................................2
2. Applicability Statement .........................................3
3. Conventions and Acronyms ........................................3
4. Background on Early Media Authorization .........................4
4.1. Backward Early Media .......................................5
4.2. Forward Early Media ........................................5
5. Applicability of RFC 3959 and RFC 3960 ..........................6
6. Overview of Operation ...........................................6
7. Limitations of the P-Early-Media Header Field ...................8
8. The P-Early-Media Header Field ..................................8
8.1. Procedures at the User Agent Client .......................10
8.2. Procedures at the User Agent Server .......................10
8.3. Procedures at the Proxy ...................................11
9. Formal Syntax ..................................................11
10. Security Considerations .......................................11
11. IANA Considerations ...........................................12
11.1. Registration of the "P-Early-Media" SIP Header Field .....12
12. Acknowledgements ..............................................12
13. References ....................................................12
13.1. Normative References .....................................12
13.2. Informative References ...................................13
1. Introduction
This document defines the use of the P-Early-Media header field for
use within SIP [1] messages in certain SIP networks to authorize the
cut-through of backward and/or forward early media when permitted by
the early media policies of the networks involved. The P-Early-Media
header field is intended for use in a SIP network, such as a 3GPP IMS
[13][14] that has the following characteristics: its early media
policy prohibits the exchange of early media between end users; it is
interconnected with other SIP networks that have unknown, untrusted,
or different policies regarding early media; and it has the
capability to "gate" (enable/disable) the flow of early media to/from
user equipment.
Within an isolated SIP network, it is possible to gate early media
associated with all endpoints within the network to enforce a desired
early media policy among network endpoints. However, when a SIP
network is interconnected with other SIP networks, only the boundary
node connected to the external network can determine which early
media policy to apply to a session established between endpoints on
different sides of the boundary. The P-Early-Media header field
provides a means for this boundary node to communicate this early
media policy decision to other nodes within the network.
Ejzak Informational [Page 2]
RFC 5009 P-Early-Media Header September 2007
2. Applicability Statement
The use of this extension is only applicable inside a "Trust Domain"
as defined in RFC 3325 [6]. Nodes in such a Trust Domain are
explicitly trusted by its users and end-systems to authorize early
media requests only when allowed by early media policy within the
Trust Domain.
This document does NOT offer a general early media authorization
model suitable for inter-domain use or use in the Internet at large.
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