Internet DRAFT - draft-goix-appsawg-enum-acct-uri
draft-goix-appsawg-enum-acct-uri
appsawg L. Goix
Internet-Draft Telecom Italia
Intended status: Experimental K. Li
Expires: December 20, 2014 Huawei Technologies
June 18, 2014
ENUM Service Registration for acct URI
draft-goix-appsawg-enum-acct-uri-07
Abstract
This document registers a Telephone Number Mapping (ENUM) service for
'acct:' URIs (Uniform Resource Identifiers).
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3.1. Reverse phone lookup . . . . . . . . . . . . . . . . . . 2
3.2. Routing of mobile social communications . . . . . . . . . 3
4. IANA Registration . . . . . . . . . . . . . . . . . . . . . . 3
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6. DNS Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
10.1. Normative References . . . . . . . . . . . . . . . . . . 7
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
ENUM (E.164 Number Mapping, [RFC6116]) is a system that uses DNS
(Domain Name Service, [RFC1034]) to translate telephone numbers, such
as '+44 1632 960123', into URIs (Uniform Resource Identifiers,
[RFC3986]), such as 'acct:user@example.com'. ENUM exists primarily
to facilitate the interconnection of systems that rely on telephone
numbers with those that use URIs to identify resources.
[I-D.ietf-appsawg-acct-uri] defines the 'acct' URI scheme as a way to
identify a user's account at a service provider.
This document registers an Enumservice for advertising acct URI
information associated with an E.164 number.
2. Terminology
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 [RFC2119].
3. Use cases
3.1. Reverse phone lookup
In this example, an address book application could issue ENUM queries
looking for 'acct' URIs corresponding to phone numbers. This could
be used to display the account identifier as well as an icon based on
the host (domain) portion of that URI.
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Similarly, an endpoint could trigger this resolution process during
inbound and/or outbound calls to discover an account associated with
the remote party.
In general the provision of an ENUM record to map a phone number into
an account may be useful for businesses or professional workers to
identify themselves publicly (in a similar way as vCard enum
records).
3.2. Routing of mobile social communications
The Open Mobile Alliance (OMA) develops mobile service enabler
specifications, which support the creation of interoperable end-to-
end mobile services independent of the underlying wireless platforms,
such as GSM (Global System for Mobile communications), UMTS
(Universal Mobile Telecommunications System) and LTE (Long Term
Evolution) mobile networks. The OMA Social Network Web (SNeW)
Enabler Release [OMA-SNeW] has introduced a number of Social
Networking functionalities for mobile subscribers identified by their
MSISDN (Mobile Subscriber Integrated Services Digital Network number,
a number uniquely identifying a subscription in a mobile network),
amongst which is the ability to follow each other's social activities
across service providers.
Such functionality requires the global resolution of the MSISDN to
the corresponding account and provider, in an analogous way as MMS
routing, to identify the target endpoint for the related messages.
Although alternatives solutions exist (e.g. based on mobile network
operations and/or proprietary lookup techniques), ENUM provides a
globally accessible mechanism for enabling resolution from network
entities on behalf of an endpoint, or from an endpoint itself.
For example, a user of a service provider could request to follow the
social activities of user '+44 1632 960123'. The home SNEW Server of
the former user could perform an ENUM query to identify the 'acct'
URI corresponding to that phone number. Based on the resulting URI,
the server could then identify the SNEW Server of the target user and
route the original user's request to the appropriate endpoint.
A similar mechanism can apply to other types of social networking-
related messages or other communications targeted to a mobile
subscriber.
4. IANA Registration
As defined in [RFC6117], the following is a template covering
information needed for the registration of the Enumservice specified
in this document:
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<record>
<class>Application-Based, Ancillary</class>
<type>acct</type>
<urischeme>acct</urischeme>
<functionalspec>
<paragraph>
This Enumservice indicates that the resource
can be identified by the associated 'acct' URI
<xref target='I-D.ietf-appsawg-acct-uri' />.
</paragraph>
</functionalspec>
<security>
For DNS considerations in avoiding loops when
searching for "acct" NAPTRs,
see <xref type="rfc" data="rfcTHIS"/>,
<xref target="dns">Section 6</xref>.
For security considerations,
see <xref type="rfc" data="rfcTHIS"/>,
<xref target="security">Section 7</xref>.
</security>
<usage>COMMON</usage>
<registrationdocs>
<xref type="rfc" data="rfcTHIS"/>
</registrationdocs>
<requesters>
<xref type="person" data="Laurent_Walter_Goix"/>
</requesters>
</record>
<people>
<person id="Laurent_Walter_Goix">
<name>Laurent-Walter Goix</name>
<org>Telecom Italia</org>
<uri>mailto:laurentwalter.goix@telecomitalia.it</uri>
<updated>2014-06-18</updated>
</person>
</people>
[Note for RFC-Editor: Please replace any instance of rfcTHIS with the
RFC number of this document before publication]
5. Examples
The following is an example of the use of the Enumservice registered
by this document in a NAPTR resource record for phone number +44 1632
960123.
$ORIGIN 3.2.1.0.6.9.2.3.6.1.4.4.e164.arpa.
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IN NAPTR 10 100 "u" "E2U+acct" "!^.*$!acct:441632960123@foo.com!" .
IN NAPTR 10 101 "u" "E2U+acct" "!^.*$!acct:john.doe@example.com!" .
Note that in the first record, the revealed information is limited to
the domain of the service provider serving that user as the userpart
of the acct URI simply replicates the phone number.
6. DNS Considerations
There may not be any "E2U+acct" NAPTRs returned in response to the
original ENUM query on the requested telephone number, but other
terminal ENUM NAPTRs that include tel: URLs [RFC3966] (e.g.,
"voice:tel" or "pstn:tel" or "SMS:tel" or "MMS:tel" - see [RFC6118])
may be present.
The application that made that ENUM query may choose to re-submit
ENUM queries for any E.164 numbers included in those returned
terminal NAPTRs. Doing so may cause a query loop (e.g., the ENUM
records returned from subsequent queries may refer to the telephone
number already considered). If applications choose to perform
subsequent ENUM queries using telephone numbers retrieved from
earlier queries, these applications MUST be aware of the potential
for query loops, and MUST be prepared to abort the set of queries if
such a loop is detected.
This is a similar issue to the referential loop issue caused by
processing non-terminal NAPTR queries, as mentioned in section 5.2.1
of [RFC6116], and a similar technique to mitigate this issue can be
used; an application searching for records with "acct" Enumservice
may consider that submitting a chain of more that 5 ENUM queries
without finding such a record indicates that a referential loop has
been entered, and the chain of queries SHOULD be abandoned.
7. Security Considerations
DNS, as used by ENUM, is a global, distributed database. Should
implementers of this specification use e164.arpa or any other
publicly available domain as the tree for maintaining PSTN
Enumservice data, this information would be visible to anyone
anonymously.
Carriers, service providers, and other users may choose not to
publish such information in the public e164.arpa tree. They may
instead simply publish this in an internal ENUM infrastructure that
is only able to be queried by trusted elements of their network, thus
limiting threats.
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For security considerations that apply to all Enumservices, please
refer to [RFC6116], section 7.
It is important to note that the ENUM record itself does not need to
contain any personal information but only contains a pointer to an
account identifier. This identifier may be queried to discover
pointers to personal information (e.g. social network information)
endpoints and an authorisation mechanism may be in place in that
context with any level of granularity although it is out of scope of
this document.
Technically, ENUM records themselves could contain pointers to the
same endpoints. However the visibility of ENUM records cannot be
controlled based on the requesting entity. In that context the
simple mapping of the phone number to the account identifier,
notwithstanding the disclosure of the association itself, still
enables the reuse of more advanced access policies.
Revealing an 'acct' URI by itself is unlikely to introduce many
privacy concerns, although, depending on the structure of the URI, it
might reveal the full name or employer of the target. The use of
anonymous URIs mitigates this risk.
Unlike a traditional telephone number, the endpoint identified by an
'acct' URI may require that requesting entities provide cryptographic
credentials for authentication and authorization before messages are
exchanged. ENUM can actually provide far greater protection from
unwanted requesting entities than does the existing PSTN, despite the
public availability of ENUM records.
More serious security concerns are associated with potential attacks
against an underlying system (for example, social network system)
using the 'acct' URI. For this reason, underlying system should have
a number of security requirements that call for authentication,
integrity and confidentiality properties, and similar measures to
prevent such attacks. And this is out of scope of this document.
8. IANA Considerations
This document requests the IANA registration of the Enumservice with
Type "acct" according to the definitions in this document, [RFC6116]
and [RFC6117].
Details of the registration are given in Section 4.
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9. Acknowledgements
The authors would like to thank Gonzalo Salgueiro, Paul Jones,
Lawrence Conroy, Enrico Marocco, Bert Greevenbosch and Bernie
Hoeneisen for their valuable feedback to improve this document.
10. References
10.1. Normative References
[I-D.ietf-appsawg-acct-uri]
Saint-Andre, P., "The 'acct' URI Scheme", draft-ietf-
appsawg-acct-uri-07 (work in progress), January 2014.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC3966] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC
3966, December 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.
[RFC6116] Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to
Uniform Resource Identifiers (URI) Dynamic Delegation
Discovery System (DDDS) Application (ENUM)", RFC 6116,
March 2011.
[RFC6117] Hoeneisen, B., Mayrhofer, A., and J. Livingood, "IANA
Registration of Enumservices: Guide, Template, and IANA
Considerations", RFC 6117, March 2011.
[RFC6118] Hoeneisen, B. and A. Mayrhofer, "Update of Legacy IANA
Registrations of Enumservices", RFC 6118, March 2011.
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10.2. Informative References
[OMA-SNeW]
Open Mobile Alliance, "Social Network Web Enabler", OMA-
ER-SNeW-V1_0
http://technical.openmobilealliance.org/Technical/
release_program/snew_v1_0.aspx, Aug 2013.
Authors' Addresses
Laurent-Walter Goix
Telecom Italia
Via Golgi, 42
Milano 20133
Italy
Email: laurentwalter.goix@telecomitalia.it
Kepeng Li
Huawei Technologies
Huawei Base, Bantian, Longgang District
Shenzhen 518129
P. R. China
Phone: +86-755-28971807
Email: likepeng@huawei.com
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