draft-ietf-ecrit-held-routing-00.txt   draft-ietf-ecrit-held-routing-01.txt 
ECRIT J. Winterbottom ECRIT J. Winterbottom
Internet-Draft Winterb Consulting Services Internet-Draft Winterb Consulting Services
Updates: RFC6881, RFC5985 H. Tschofenig Updates: RFC6881, RFC5985 H. Tschofenig
(if approved) (if approved)
Intended status: Standards Track L. Liess Intended status: Standards Track L. Liess
Expires: June 25, 2015 Deutsche Telekom Expires: September 8, 2015 Deutsche Telekom
December 22, 2014 March 7, 2015
A Routing Request Extension for the HELD Protocol A Routing Request Extension for the HELD Protocol
draft-ietf-ecrit-held-routing-00.txt draft-ietf-ecrit-held-routing-01.txt
Abstract Abstract
In many circumstances public LoST servers or a distributed network of In many circumstances public LoST servers or a distributed network of
forest guides linking public LoST servers is not available. In such forest guides linking public LoST servers is not available. The
environments the general ECRIT calling models breakdown. However, general ECRIT calling models breakdown without publically accessible
location servers operating in these areas are often privy to the LoST servers. Sometimes location servers may have access to
necessary information to reach emergency and other services. This emergency routing information. This document defines an extension to
document describes a solution where by the routing information may be the HELD protocol so a location request can include a request for
obtained from a location server using a simple extension to the HELD routing information and allowing the subsequent location response to
protocol. include routing information.
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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Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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skipping to change at page 2, line 21 skipping to change at page 2, line 21
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. HELD Schema Extension . . . . . . . . . . . . . . . . . . . . 8 5. HELD Schema Extension . . . . . . . . . . . . . . . . . . . . 8
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 10 7. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 10
8. Security Considerations . . . . . . . . . . . . . . . . . . . 10 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
9.1. URN sub-namespace registration for 9.1. URN sub-namespace registration for
'urn:ietf:params:xml:ns:geopriv:held:ri' . . . . . . . . . 11 'urn:ietf:params:xml:ns:geopriv:held:ri' . . . . . . . . . 10
9.2. XML Schema Registration . . . . . . . . . . . . . . . . . 11 9.2. XML Schema Registration . . . . . . . . . . . . . . . . . 11
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
11.1. Normative References . . . . . . . . . . . . . . . . . . . 12 11.1. Normative References . . . . . . . . . . . . . . . . . . . 12
11.2. Informative References . . . . . . . . . . . . . . . . . . 12 11.2. Informative References . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
In many circumstances public LoST [RFC5222] servers or a distributed The general ECRIT calling models described in [RFC6443] and
network of forest guides linking public LoST servers is not [RFC6881]require a local LoST server or network of forest guides in
available. In such environments the general ECRIT calling models order to determine the address of the PSAP in the best position to
breakdown. Location servers operating in these areas are often privy handle a call. Networks of forest guides have not eventuated and
to the necessary information to reach emergency and other services. while PSAPs are moving towards IP networks, LoST server deployment is
This document describes how adding an extension to the HELD protocol not ubiquitous. Some regions and countries have expressed reluctance
[RFC5985] can used to extract this information for a location to deploy LoST servers making aspects of the current ECRIT
information server in the absence of a LoST server or network of architecture hard to realize.
forest guides.
Evolving architectures in Europe to address regulatory requirements,
such as [M493], couple location and routing information in the access
network whilst using a softswitch-centric approach to emergency call
processing. This document describes adding an extension to the HELD
protocol [RFC5985] so that a location information server can provide
emergency routing information in the absence of a LoST server or
network of forest guides.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
The terms LIS, ESRP, VSP and PSAP are used as defined in [RFC6443]. The terms LIS, ESRP, VSP and PSAP are used as defined in [RFC6443].
The term "Access Network Provider" is used as defined in [RFC5687] The term "Access Network Provider" is used as defined in [RFC5687]
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LoST server discovery is a domain based activity, similar to the LIS LoST server discovery is a domain based activity, similar to the LIS
discovery technique. However, unlike the LIS that is a domain bound discovery technique. However, unlike the LIS that is a domain bound
service, a LoST server is a geographically bound service. This means service, a LoST server is a geographically bound service. This means
that for a domain that spans multiple geographic regions the LoST that for a domain that spans multiple geographic regions the LoST
server determined may not be able to provide a route to the necessary server determined may not be able to provide a route to the necessary
PSAP. When this occurs, the contacted LoST server invokes the help PSAP. When this occurs, the contacted LoST server invokes the help
of other LoST servers and this requires the deployment of forest of other LoST servers and this requires the deployment of forest
guides. guides.
At the time of writing, several countries have expressed their At the time of writing, several countries have expressed a reluctance
reluctance to deploy public LoST servers. In countries amenable to to deploy public LoST servers. In countries amenable to the use of
use of LoST and forest guides no public forest guides have been LoST and forest guides no public forest guides have been deployed.
deployed. There appears little interest from the public sector in There appears little interest from the public sector in establishing
establishing a global forest guide network. These issues pose a global forest guide network. These issues pose threats to both the
threats to both the device-centric and the softswitch-centric calling device-centric and the softswitch-centric calling approaches in terms
approaches in terms of them operating everywhere. of them operating everywhere.
The device-centric and softswitch-centric calling models both involve The device-centric and softswitch-centric calling models both involve
the notion of a LIS bound to the serving access network. In many the notion of a LIS bound to the serving access network. In many
cases the LIS already knows the destination PSAP address for any cases the LIS already knows the destination PSAP URI for any given
given location. In [RFC6881] for example, the LIS validates all location. In [RFC6881] for example, the LIS validates civic
civic locations using a location validation procedure. This locations using a location validation procedure based on the LoST
procedure is the same as a routing request and so the LIS has the protocol [RFC5222]. The LoST validation request is similar to a LoST
resulting the PSAP routing information. In other cases, the LIS routing request and provides the LIS with the same PSAP routing
information that a routing request would. In other cases, the LIS
knows the correct PSAP for a given location at provisioning time, or knows the correct PSAP for a given location at provisioning time, or
the access network might always route to the same emergency provider. the access network might always route to the same emergency provider.
Irrespective of the way in which the LIS learns the PSAP address for Irrespective of the way in which the LIS learns the PSAP URI for a
a location, the LIS will, in a great many cases, have this location, the LIS will, in a great many cases, already have this
information. information.
This document specifies an extension to the HELD protocol so that This document specifies an extension to the HELD protocol so that
emergency routing information can be requested from the LIS at the emergency routing information can be requested from the LIS at the
same time that location information is requested. The document same time that location information is requested. The document
updates [RFC6881] by requiring devices and softswitches that updates [RFC6881] by requiring devices and softswitches that
understand this specification to always request routing information understand this specification to always request routing information
to avoid the risk of query failure where no LoST server or forest to avoid the risk of query failure where no LoST server or forest
guide network is deployed. guide network is deployed.
4. Mechanism 4. Mechanism
The mechanism consists of adding an element to the HELD The mechanism consists of adding an element to the HELD
locationRequest and an element to the locationResponse. The request locationRequest and an element to the locationResponse.
element indicates that the requestor wants the LIS to provide routing
information for the location where the device is. If the LIS The request element indicates that the requestor wants the LIS to
understands the routing request and has routing information provide routing information based on the location of the end-device.
accessible it provides the information in a routingInformation If the routing request is sent with no attribute then URIs for
element included in the locationResponse. How the LIS obtains this urn:service:sos are returned. If the requestor wants routing
information is left to implementation, one possible option is that information for a specific service then they may include an optional
the LIS acquires it from a LoST server, other possibilities are service URN. If a service is specified, and the LIS does not
described in Section 3. understand the requested service then URIs for urn:service:sos are
returned.
If the LIS understands the routing request and has routing
information for the location then it includes the information in a
routingInformation element returned in the locationResponse. How the
LIS obtains this information is left to implementation, one possible
option is that the LIS acquires it from a LoST server, other
possibilities are described in Section 3.
A LIS that does not understand the routing request element ignores it A LIS that does not understand the routing request element ignores it
and returns location as normal. and returns location as normal.
A LIS that does support the routing request element SHALL support
returning URIs for urn:service:sos
A LIS that does understand the routing request element but can't A LIS that does understand the routing request element but can't
obtain routing information returns location as normal. obtain any routing information for the end-device's location SHALL
only return location information.
The routing information in the location response consists of one or A LIS that understands the routing request element but not the
more service elements which is identified by a service name. The specified service URN, returns the routing URIs for the
service name is a URI and might contain a general emergency service urn:service:sos service.
urn such as urn:service:sos or might contain a specific service urn.
For each service name a list of one or more service destinations is
provided. Each destination is expressed as a URI and each URI scheme
should only appear once in this list. The routing information is
intended to be used at the time it is received. To avoid any risks
of using stale routing information the value should not be cached by
the receiving entity.
Reusing the mapping element from the LoST findServiceResponse message The routing information in the location response consists of a
to provide the routing information was considered. However, this service element identified by a service name. The service name is a
would have meant that several of the mandatory components in the urn and might contain a general emergency service urn such as
mapping element would have had to contain ambiguous or misleading urn:service:sos or might contain a specific service urn depending on
values. Specifically, the "source" attribute is required to contain what was requested and what the LIS is able to provide. A list of
a LoST application unique string for the authoritative server. one or more service destinations is provided for the service name.
However, in the situations described in this specification there may Each destination is expressed as a URI and each URI scheme should
not be an authoritative LoST server, so any value put into this only appear once in this list. The routing URIs are intended to be
attribute would be misleading. In addition to this, routing used at the time they are received. To avoid any risks of using
information received in the manner described in this specification stale routing URIs the values MUST NOT be cached by the receiving
should not be cached by the receiver, so detailing when the routing entity.
information expires or was last updated is irrelevant.
The LoST Protocol [RFC5222] defines a <mapping> element that
describes a service region and associated service URLs. Reusing this
element from LoST to provide the routing URIs was considered.
However, this would have meant that several of the mandatory
components in the <mapping> element would have had to contain
ambiguous or misleading values. Specifically, the "source" attribute
is required to contain a LoST application unique string for the
authoritative server. However, in the situations described in this
specification there may not be an authoritative LoST server, so any
value put into this attribute would be misleading. In addition to
this, routing information received in the manner described in this
specification should not be cached by the receiver, so detailing when
the routing information expires or was last updated is irrelevant.
5. HELD Schema Extension 5. HELD Schema Extension
This section describes the schema extension to HELD. This section describes the schema extension to HELD.
<?xml version="1.0"?> <?xml version="1.0"?>
<xs:schema <xs:schema
targetNamespace="urn:ietf:params:xml:ns:geopriv:held:ri" targetNamespace="urn:ietf:params:xml:ns:geopriv:held:ri"
xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:ri="urn:ietf:params:xml:ns:geopriv:held:ri" xmlns:ri="urn:ietf:params:xml:ns:geopriv:held:ri"
xmlns:xml="http://www.w3.org/XML/1998/namespace" xmlns:xml="http://www.w3.org/XML/1998/namespace"
elementFormDefault="qualified" attributeFormDefault="unqualified"> elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:element name="requestRoutingInformation"> <xs:element name="requestRoutingInformation">
<xs:complexType name="empty"/> <xs:complexType name="empty">
<xs:attribute name="service" type="xs:anyUri"
use="optional" default="urn:service:sos"/>
</xs:complexType>
</xs:element> </xs:element>
<xs:complexType name="service"> <xs:complexType name="service">
<xs:complextContent> <xs:complexContent>
<xs:restriction base="xs:anyType"> <xs:restriction base="xs:anyType">
<xs:sequence> <xs:sequence>
<xs:element name="dest" type="xs:anyURI" <xs:element name="dest" type="xs:anyURI"
maxOccurs="unbounded"/> maxOccurs="unbounded"/>
</xs:sequence> </xs:sequence>
<xs:attribute name="serviceUri" type="xs:anyURI" <xs:attribute name="serviceUri" type="xs:anyURI"
use="required"/> use="required"/>
</xs:restriction> </xs:restriction>
</xs:complexContent> </xs:complexContent>
</xs:complexType> </xs:complexType>
<xs:element name="routingInformation" type="ri:riType"/> <xs:element name="routingInformation" type="ri:riType"/>
<xs:complexType name="riType"> <xs:complexType name="riType">
<xs:complexContent> <xs:complexContent>
<xs:restriction base="xs:anyType"> <xs:restriction base="xs:anyType">
<xs:sequence> <xs:sequence>
<xs:element name="service" type="ri:service" <xs:element name="service" type="ri:service"/>
maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax" <xs:any namespace="##other" processContents="lax"
minOccurs="0" maxOccurs="unbounded"/> minOccurs="0" maxOccurs="unbounded"/>
</xs:sequence> </xs:sequence>
<xs:anyAttribute namespace="##any" processContents="lax"/> <xs:anyAttribute namespace="##any" processContents="lax"/>
</xs:restriction> </xs:restriction>
</xs:complexContent> </xs:complexContent>
</xs:complexType> </xs:complexType>
</xs:schema> </xs:schema>
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<locationUriSet expires="2006-01-01T13:00:00.0Z"> <locationUriSet expires="2006-01-01T13:00:00.0Z">
<locationURI> <locationURI>
https://ls.example.com:9768/357yc6s64ceyoiuy5ax3o https://ls.example.com:9768/357yc6s64ceyoiuy5ax3o
</locationURI> </locationURI>
<locationURI> <locationURI>
sip:9769+357yc6s64ceyoiuy5ax3o@ls.example.com sip:9769+357yc6s64ceyoiuy5ax3o@ls.example.com
</locationURI> </locationURI>
</locationUriSet> </locationUriSet>
<routingInformation <routingInformation
xmlns="urn:ietf:params:xml:ns:geopriv:held:ri"> xmlns="urn:ietf:params:xml:ns:geopriv:held:ri">
<service serviceUri="urn:service:sos:police"> <service serviceUri="urn:service:sos">
<dest>sip:nypd@example.com</dest> <dest>sip:112@example.com</dest>
<dest>sips:nypd@example.com</dest> <dest>sips:112@example.com</dest>
<dest>xmpp:nypd@example.com</dest> <dest>xmpp:112@example.com</dest>
</service>
<service serviceUri="urn:service:sos:fire">
<dest>sip:fd@ny.example.com</dest>
<dest>sips:fd@ny.example.com</dest>
<dest>xmpp:fd@ny.example.com</dest>
</service> </service>
</routingInformation> </routingInformation>
</locationResponse> </locationResponse>
Figure 4: Example Location Response Figure 4: Example Location Response
7. Privacy Considerations 7. Privacy Considerations
This document makes no changes that require privacy considerations This document makes no changes that require privacy considerations
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Registrant Contact: IETF, ECRIT working group, (ecrit@ietf.org), Registrant Contact: IETF, ECRIT working group, (ecrit@ietf.org),
James Winterbottom (a.james.winterbottom@gmail.com). James Winterbottom (a.james.winterbottom@gmail.com).
The XML for this schema can be found as the entirety of Section 5 The XML for this schema can be found as the entirety of Section 5
of this document. of this document.
10. Acknowledgements 10. Acknowledgements
We would like to thank Wilfried Lange for sharing his views with us. We would like to thank Wilfried Lange for sharing his views with us.
We would also like to thank Bruno Chatras for his early review We would also like to thank Bruno Chatras for his early review
comments and Bernd Henschel for his support. comments and Bernd Henschel for his support. Thanks to Roger
Marshall and Randy Gellens for their helpful suggestions.
11. References 11. References
11.1. Normative References 11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004. January 2004.
skipping to change at page 12, line 42 skipping to change at page 12, line 36
[RFC6443] Rosen, B., Schulzrinne, H., Polk, J., and A. Newton, [RFC6443] Rosen, B., Schulzrinne, H., Polk, J., and A. Newton,
"Framework for Emergency Calling Using Internet "Framework for Emergency Calling Using Internet
Multimedia", RFC 6443, December 2011. Multimedia", RFC 6443, December 2011.
[RFC6881] Rosen, B. and J. Polk, "Best Current Practice for [RFC6881] Rosen, B. and J. Polk, "Best Current Practice for
Communications Services in Support of Emergency Calling", Communications Services in Support of Emergency Calling",
BCP 181, RFC 6881, March 2013. BCP 181, RFC 6881, March 2013.
11.2. Informative References 11.2. Informative References
[M493] European Telecommunications Standards Institute,
"Functional architecture to support European requirements
on emergency caller location determination and transport",
ES 203 178, V 1.0.5, December 2014.
[RFC5986] Thomson, M. and J. Winterbottom, "Discovering the Local [RFC5986] Thomson, M. and J. Winterbottom, "Discovering the Local
Location Information Server (LIS)", RFC 5986, Location Information Server (LIS)", RFC 5986,
September 2010. September 2010.
[RFC6155] Winterbottom, J., Thomson, M., Tschofenig, H., and R. [RFC6155] Winterbottom, J., Thomson, M., Tschofenig, H., and R.
Barnes, "Use of Device Identity in HTTP-Enabled Location Barnes, "Use of Device Identity in HTTP-Enabled Location
Delivery (HELD)", RFC 6155, March 2011. Delivery (HELD)", RFC 6155, March 2011.
[RFC6915] Bellis, R., "Flow Identity Extension for HTTP-Enabled [RFC6915] Bellis, R., "Flow Identity Extension for HTTP-Enabled
Location Delivery (HELD)", RFC 6915, April 2013. Location Delivery (HELD)", RFC 6915, April 2013.
 End of changes. 23 change blocks. 
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