Internet DRAFT - draft-holmberg-sipcore-received-realm
draft-holmberg-sipcore-received-realm
SIPCORE Working Group C. Holmberg
Internet-Draft Ericsson
Intended status: Standards Track J. Jiang
Expires: June 19, 2015 China Mobile
December 16, 2014
Via header field parameter to indicate received realm
draft-holmberg-sipcore-received-realm-04.txt
Abstract
This specification defines a new Session Initiation Protocol (SIP)
Via header field parameter, "received-realm", which allows a SIP
entity acting as an entry point to a transit network to indicate from
which adjacent upstream network a SIP request is received, using a
network realm value associated with the adjacent network.
Status of This Memo
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This Internet-Draft will expire on June 19, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Use-Case: Transit Network Application Services . . . . . 3
1.3. Use-Case: Transit Network Routing . . . . . . . . . . . . 3
2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
5. User Agent and Proxy behavior . . . . . . . . . . . . . . . . 4
5.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 4
5.2. Behavior of a SIP entity acting as a network entry point 4
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Example 1 . . . . . . . . . . . . . . . . . . . . . . . . 5
6.2. Example 2 . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.2. ABNF . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
8.1. 'received-realm' Via header field parameter . . . . . . . 6
9. Security Considerations . . . . . . . . . . . . . . . . . . . 6
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
11. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 6
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
12.1. Normative References . . . . . . . . . . . . . . . . . . 7
12.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
1.1. General
When SIP sessions are established between networks belonging to
different operators, or between interconnected networks belonging to
the same operator (or enterprise), the SIP requests might traverse
transit network.
Such transit networks might provide different kind of services. In
order to do that, a transit network often needs to know to which
operator (or enterprise) the adjacent upstream network, from which
the SIP session initiation request is received, belongs.
This specification defines a new Session Initiation Protocol (SIP)
Via header field parameter, "received-realm", which allows a SIP
entity acting as an entry point to a transit network to indicate from
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which adjacent upstream network a SIP request is received, using a
network realm value associated with the adjacent network.
NOTE: As the adjacent network can be an enterprise network, an Inter
Operator Identifier (IOI) cannot be used to identity the network, as
IOIs are not defined for enterprise networks.
The following sections describe use-case where the information is
needed.
1.2. Use-Case: Transit Network Application Services
The 3rd Generation Partnership Project (3GPP) TS 23.228 specifies how
an IP Multimedia Subsystem (IMS) network can be used to provide
transit funtionality. An operator can use its IMS network to provide
transit functionality e.g. to non-IMS customers, to enterprise
networks, and to other network operators.
The transit network operator can provide application services to the
networks for which it is providing transit functionality. Transit
application services are typically not provided per user basis, as
the transit network does not have access to the user profiles of the
networks for which the application services are provided. Instead,
the application services are provided per served network.
When a SIP entity that provides application services (e.g. an
Application Server) within a transit network receives a SIP request,
in order to apply the correct services it needs to know the adjacent
upstream network from which the SIP request is received.
1.3. Use-Case: Transit Network Routing
A transit network operator normally interconnects to many diferent
operators, including other transit network operators, and provides
transit routing of SIP requests received from one operator network
towards the destination. The destination can be within an operator
network to which the transit network operator has a direct
interconnect, or within an operator network that only can be reached
via one or more interconnected transit operators.
For each customer, i.e. interconnected network operator for which,
the transit network operator routes SIP requests towards the
requested destination a set of transit routing polices are defined.
These policies are used to determine how a SIP request shall be
routed towards the requested destination to meet the agreement the
transit network operator has with its customer.
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When a SIP entity that performs the transit routing functionality
receives a SIP request, in order to apply the correct set of transit
routing policies, it needs to know from which of its customers, i.e.
adjacent upstream network, the SIP request is received.
2. Applicability
The mechanism defined in this specification MUST only be used by SIP
entities that are able to verify from which adjacent upstream network
a SIP request is received.
The mechanism for verifying from which adjacent upstream network a
SIP request is received is outside the scope of this specification.
3. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119
[RFC2119].
4. Definitions
SIP entity: SIP User Agent (UA), or SIP proxy, as defined in RFC
3261.
Adjacent upstream SIP network: The adjacent SIP network in the
direction from which a SIP request is received.
Network entry point: A SIP entity on the border of network, which
recieves SIP requests from adjacent upstream networks.
Inter Operator Identifier (IOI): A globally unique identifier to
correlate billing information generated within the IP Multimedia
Subsystem (IMS).
5. User Agent and Proxy behavior
5.1. General
This section describes how a SIP entity, acting as an entry point to
a network, uses the "received-realm" Via header field parameter.
5.2. Behavior of a SIP entity acting as a network entry point
When a SIP entity, acting as a network entry point, forwards a SIP
request, or initiates a SIP request on its own (e.g. a PSTN gateway),
the SIP entity adds a Via header field to the SIP request, according
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to the procedures in RFC 3261 [RFC3261]. In addition, if the SIP
entity is able to assert the adjacent upstream network, and if the
SIP entity is aware of a network realm value defined for that
network, the SIP entity can add a "received-realm" Via header field
parameter, conveying the network realm value, to the Via header field
added to the SIP request.
6. Examples
6.1. Example 1
TBD
Operator 1 T_EP T_AS
- INVITE --------->
Via: IP_UA
- INVITE ---------------------------->
Via: IP_TEP; received-realm=operator_1.com
Via: IP_UA; received=IP_UA
<- 200 OK ----------------------------
Via: IP_TEP; received-realm=operator_1.co
Via: IP_UA; received=IP_UA
<- 200 OK------
Via: IP_UA; received=IP_UA
6.2. Example 2
TBD
7. Syntax
7.1. General
This section describes the syntax extensions to the ABNF syntax
defined in RFC 3261 [RFC3261], by defining a new Via header field
parameter, "received-realm". The ABNF defined in this specification
is conformant to RFC 5234 [RFC5234]. "EQUAL" and "hostname" are
defined in RFC 3261 [RFC3261]. "DIGIT" is defined in RFC 5234
[RFC5234]
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7.2. ABNF
via-params =/ received-realm
received-realm = "received-realm" EQUAL hostname
8. IANA Considerations
8.1. 'received-realm' Via header field parameter
This specification defines a new Via header field parameter called
received-realm in the "Header Field Parameters and Parameter Values"
sub-registry as per the registry created by [RFC3968]. The syntax is
defined in Section 7. The required information is:
Predefined
Header Field Parameter Name Values Reference
---------------------- --------------------- ---------- ---------
Via received-realm No RFCXXXX
9. Security Considerations
TBD
10. Acknowledgements
TBD
11. Change Log
[RFC EDITOR NOTE: Please remove this section when publishing]
Changes from draft-holmberg-received-realm-03
o New version due to expiration.
Changes from draft-holmberg-received-realm-02
o New version due to expiration.
Changes from draft-holmberg-received-realm-01
o New version due to expiration.
Changes from draft-holmberg-received-realm-00
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o New version due to expiration.
12. References
12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261,
June 2002.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
12.2. Informative References
[RFC3968] Camarillo, G., "The Internet Assigned Number Authority
(IANA) Header Field Parameter Registry for the Session
Initiation Protocol (SIP)", BCP 98, RFC 3968, December
2004.
Authors' Addresses
Christer Holmberg
Ericsson
Hirsalantie 11
Jorvas 02420
Finland
Email: christer.holmberg@ericsson.com
Yi Jiang
China Mobile
No.32 Xuanwumen West Street
Beijing Xicheng District 100053
P.R. China
Email: jiangyi@chinamobile.com
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