One document matched: draft-winterbottom-dispatch-locparam-01.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
<rfc category="std" ipr="trust200902" updates="RFC6442" docName="draft-winterbottom-dispatch-locparam-01.txt">
<?rfc strict="yes" ?>
<?rfc toc="yes"?>
<?rfc tocdepth="4"?>
<?rfc symrefs="yes"?>
<?rfc iprnotified="no" ?>
<?rfc sortrefs="yes" ?>
<?rfc compact="yes" ?>
<?rfc subcompact="no" ?>
<front>
<title abbrev="Location Parameter">Location Source Parameter for the SIP Geolocation Header Field</title>
<author initials="J." surname="Winterbottom" fullname="James Winterbottom">
<organization>Winterb Consulting Services</organization>
<address>
<postal>
<street/>
<city>Gwynneville</city>
<region>NSW</region>
<code>2500</code>
<country>AU</country>
</postal>
<phone>+61 448 266004</phone>
<email>a.james.winterbottom@gmail.com</email>
</address>
</author>
<author initials="L." surname="Liess" fullname="Laura Liess">
<organization>Deutsche Telekom</organization>
<address>
<postal>
<street>Heinrich-Hertz Str, 3-7</street>
<city>Darmstadt</city>
<code>64295</code>
<country>Germany</country>
</postal>
<phone></phone>
<email>l.liess@telekom.de</email>
<uri>www.telekom.de</uri>
</address>
</author>
<author initials="B." surname="Chatras" fullname="Bruno Chatras">
<organization>Orange Labs</organization>
<address>
<postal>
<street>38-40 rue du General Leclerc</street>
<city>Issy Moulineaux Cedex 9</city>
<code>F-92794</code>
<country>France</country>
</postal>
<phone></phone>
<email>bruno.chatras@orange.com</email>
</address>
</author>
<author initials="A." surname="Hutton" fullname="Andrew Hutton">
<organization>Unify</organization>
<address>
<postal>
<street>Technology Drive</street>
<city>Nottingham</city>
<code>NG9 1LA</code>
<country>UK</country>
</postal>
<phone></phone>
<email>andrew.hutton@unify.com</email>
</address>
</author>
<date year="2015"/>
<area>RAI</area>
<workgroup>Dispatch</workgroup>
<keyword>Internet-Draft</keyword>
<keyword>Emergency</keyword>
<keyword>Call</keyword>
<keyword>Location</keyword>
<abstract>
<t>There are some circumstances where a geolocation header field may contain more than
one location value. Knowing the identity of the node adding the location value allows
the recipient more freedom in selecting the value to look at first rather than relying
solely on the order of the location values.
</t>
</abstract>
</front>
<middle>
<!-- ***************************************************************************************************** -->
<section anchor="intro" title="Introduction">
<t>
The SIP geolocation specification <xref target="RFC6442"/> describes a SIP
header field that is used to indicate that the SIP message is conveying location
information. The specification suggests that only one location value should
be conveyed. However, some communications architectures, such as 3GPP
<xref target="TS23-167"/> and ETSI <xref target="M493"/>, prefer to use
information provided by edge-proxies or acquired through the use of core-network
nodes, before using information provided solely by user equipment (UE). These
solutions don't preclude the use of UE provided location but require a means of
being able to distinguish the identity of the node adding the location value to
the SIP message from that provided by the UE.
<xref target="RFC6442"/> stipulates that the order of location values in the
geolocation header field aligns with the order in which they were added to the
header field. Whilst this order provides guidance to the recipient as to which
values were added to the message earlier in the communication chain, it does not
provide any indication of which node actually added the location value. Knowing
the identity of the entity that added the location to the message allows the
recipient to choose which location to consider first rather than relying solely
on the order of the location values in the geolocation header field.
</t>
<t>
This document adds a location-source (loc-src) parameter to the location values in
<xref target="RFC6442"/> so that the entity adding the location value to
geolocation header field can identify itself using its hostname. How the entity
adding the location value to the header field obtains the location information
is out of scope of this document.
</t>
</section>
<!-- ***************************************************************************************************** -->
<section anchor="terminology" title="Terminology">
<t>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 <xref target="RFC2119"/>.
</t>
</section>
<!-- ***************************************************************************************************** -->
<?rfc needLines="30" ?>
<section anchor="rationale" title="Rationale">
<t>The primary intent of the parameter defined in this specific is for use in
emergency calling. There are various architectures defined for providing
emergency calling using SIP-based messaging. Each has it own characteristics
with corresponding pros and cons. All of them allow the UE to provide location
information, however, many also attach other sources of location information to
support veracity checks, provide backup information, or to be used as the primary
location. This document makes no attempt to comment on these various architectures
or the rationale for them wishing to include multiple location values. It does
recognize that these architectures exist and that there is a need to identify
the entity adding the location information.
</t>
<t>The parameter defined in this specification is intended to be used in trust
domains where s Spec(T) as described in <xref target="RFC3325"/> exists.
</t>
</section>
<section anchor="mechanism" title="Mechanism">
<t>The mechanism employed adds a parameter to the location value defined in
<xref target="RFC6442"/> that identifies the hostname of the entity adding the location
value to the geolocation header field. The Augmented BNF (ABNF) <xref target="RFC5234"/> for this parameter is
shown in <xref target="ABNF"/>.
</t>
<figure anchor="ABNF" title="Location Source"><artwork><![CDATA[
location-source = “loc-src=” (host / other-loc-src)
other-loc-src = token
]]></artwork></figure>
<t>Only a fully qualified host name is valid, an IP address MUST NOT be added by
an entity conforming with this specification. If a node conforming to this specification
receives a geolocation header field with a loc-src parameter containing an
IP address then the parameter MUST be removed.</t>
<t>Any proxy adding a location value to a geolocation header field SHOULD also
add its host name using the loc-src parameter so that it is clearly
identified as the node adding the location. A UE MUST NOT provide a loc-src
parameter value. If a proxy receives a message from an untrusted source with
the loc-src parameter set then it MUST remove the loc-src parameter before
passing the message into a trusted network.
</t>
</section>
<!-- ***************************************************************************************************** -->
<!-- ***************************************************************************************************** -->
<section anchor="example" title="Example">
<t>
The following example shows a SIP INVITE message containing a geolocation header
field with two location values. The first location value points to a PIDF-LO
in the SIP body using a content-indirection (cid:) URI per <xref target="RFC4483"/>
and this is provided by the UE. The second location value is an https URI the
provided by a proxy which identifies itself using the loc-src parameter.
</t>
<figure anchor="locationRequest" title="Example Location Request."><artwork><![CDATA[
INVITE sips:bob@biloxi.example.com SIP/2.0
Via: SIPS/2.0/TLS pc33.atlanta.example.com;branch=z9hG4bK74bf9
Max-Forwards: 70
To: Bob <sips:bob@biloxi.example.com>
From: Alice <sips:alice@atlanta.example.com>;tag=9fxced76sl
Call-ID: 3848276298220188511@atlanta.example.com
Geolocation: <cid:target123@atlanta.example.com>,
<https://lis.example.com:8222/y77syc7cuecbh>;
loc-src=edgeproxy.example.com
Geolocation-Routing: yes
Accept: application/sdp, application/pidf+xml
CSeq: 31862 INVITE
Contact: <sips:alice@atlanta.example.com>
Content-Type: multipart/mixed; boundary=boundary1
Content-Length: ...
]]></artwork></figure>
</section>
<!-- ***************************************************************************************************** -->
<!-- ***************************************************************************************************** -->
<section anchor="privacy" title="Privacy Considerations">
<t>This document doesn't change any of the privacy considerations described in
<xref target="RFC6442"/>. While the addition of the loc-src parameter does
provide an indicator of the entity that added the location in the signaling
path this provides little more exposure than a proxy identity being added to the
record-route header field.</t>
</section>
<!-- ***************************************************************************************************** -->
<section anchor="security" title="Security Considerations">
<t>This document introduces the ability of a proxy or middle box to insert
a host name indicating the that they added the specific location value to the
geolocation header field. The intent is for this field to be used by the location
recipient in the event that the SIP message contains multiple location values.
As a consequence this parameter should only be used by the location recipient
in a trusted network.
</t>
</section>
<!-- ***************************************************************************************************** -->
<section anchor="iana" title="IANA Considerations">
<section title="Registration of loc-src Parameter for geolocation header field">
<t>This document calls for IANA to register a new SIP header parameter as per the guidelines
in <xref target="RFC3261"/>, which will be added to header sub-registry under
http://www.iana.org/assignments/sip-parameters.
<list style="hanging">
<t hangText="Header Field:">geolocation</t>
<t hangText="Parameter Name:">loc-src</t>
</list>
</t>
</section>
</section>
<!-- ***************************************************************************************************** -->
<section title="Acknowledgements">
<t>NONE</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119"?>
<?rfc include="reference.RFC.3261"?>
<?rfc include="reference.RFC.6442"?>
<?rfc include="reference.RFC.5234"?>
<?rfc include="reference.RFC.3325"?>
</references>
<references title="Informative References">
<?rfc include="reference.RFC.4483"?>
<reference anchor="TS23-167">
<front>
<title>3rd Generation Partnership Project;
Technical Specification Group Services and System Aspects;
IP Multimedia Subsystem (IMS) emergency sessions
</title>
<author>
<organization abbrev="3GPP">
3rd Generation Partnership Project
</organization>
</author>
<date month="March" year="2015" />
</front>
<seriesInfo name="TS" value="23.167" />
<seriesInfo name="V" value="12.1.0" />
</reference>
<reference anchor="M493">
<front>
<title>Functional architecture to support European requirements
on emergency caller location determination and transport</title>
<author>
<organization abbrev="ETSI">
European Telecommunications Standards Institute
</organization>
</author>
<date month="December" year="2014" />
</front>
<seriesInfo name="ES" value="203 178" />
<seriesInfo name="V" value="1.0.5" />
</reference>
</references>
</back>
</rfc>
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