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<pre>Internet Engineering Task Force (IETF) M. Jones
Request for Comments: 6408 Bridgewater Systems
Updates: <a href="./rfc3588">3588</a> J. Korhonen
Category: Standards Track Nokia Siemens Networks
ISSN: 2070-1721 L. Morand
Orange Labs
November 2011
<span class="h1">Diameter Straightforward-Naming Authority Pointer (S-NAPTR) Usage</span>
Abstract
The Diameter base protocol specifies mechanisms whereby a given realm
may advertise Diameter nodes and the supported transport protocol.
However, these mechanisms do not reveal the Diameter applications
that each node supports. A peer outside the realm would have to
perform a Diameter capability exchange with every node until it
discovers one that supports the required application. This document
updates <a href="./rfc3588">RFC 3588</a>, "Diameter Base Protocol", and describes an
improvement using an extended format for the Straightforward-Naming
Authority Pointer (S-NAPTR) application service tag that allows for
discovery of the supported applications without doing Diameter
capability exchange beforehand.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in <a href="./rfc5741#section-2">Section 2 of RFC 5741</a>.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
<a href="http://www.rfc-editor.org/info/rfc6408">http://www.rfc-editor.org/info/rfc6408</a>.
<span class="grey">Jones, et al. Standards Track [Page 1]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-2" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
<a href="#section-1">1</a>. Introduction ....................................................<a href="#page-2">2</a>
<a href="#section-2">2</a>. Terminology .....................................................<a href="#page-3">3</a>
<a href="#section-2.1">2.1</a>. Requirements Language ......................................<a href="#page-3">3</a>
<a href="#section-3">3</a>. Extended NAPTR Service Field Format .............................<a href="#page-3">3</a>
<a href="#section-3.1">3.1</a>. IETF Standards Track Diameter Applications .................<a href="#page-5">5</a>
<a href="#section-3.2">3.2</a>. Vendor-Specific Diameter Applications ......................<a href="#page-5">5</a>
<a href="#section-4">4</a>. Backwards Compatibility .........................................<a href="#page-5">5</a>
<a href="#section-5">5</a>. Extended NAPTR-Based Diameter Peer Discovery ....................<a href="#page-6">6</a>
<a href="#section-5.1">5.1</a>. Examples ...................................................<a href="#page-7">7</a>
<a href="#section-6">6</a>. Usage Guidelines ................................................<a href="#page-8">8</a>
<a href="#section-7">7</a>. IANA Considerations .............................................<a href="#page-9">9</a>
<a href="#section-7.1">7.1</a>. IETF Diameter Application Service Tags .....................<a href="#page-9">9</a>
<a href="#section-7.2">7.2</a>. 3GPP Diameter Application Service Tags .....................<a href="#page-9">9</a>
<a href="#section-7.3">7.3</a>. WiMAX Forum Diameter Application Service Tags .............<a href="#page-10">10</a>
<a href="#section-7.4">7.4</a>. Vendor-Specific Diameter Application Service Tags .........<a href="#page-10">10</a>
<a href="#section-7.5">7.5</a>. Diameter Application Protocol Tags ........................<a href="#page-11">11</a>
<a href="#section-8">8</a>. Security Considerations ........................................<a href="#page-11">11</a>
<a href="#section-9">9</a>. Acknowledgments ................................................<a href="#page-11">11</a>
<a href="#section-10">10</a>. References ....................................................<a href="#page-12">12</a>
<a href="#section-10.1">10.1</a>. Normative References .....................................<a href="#page-12">12</a>
<a href="#section-10.2">10.2</a>. Informative References ...................................<a href="#page-14">14</a>
<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
The Diameter base protocol [<a href="./rfc3588" title=""Diameter Base Protocol"">RFC3588</a>] specifies three mechanisms for
Diameter peer discovery. One of these involves the Diameter
implementation performing a Naming Authority Pointer (NAPTR) query
[<a href="./rfc3403" title=""Dynamic Delegation Discovery System (DDDS) Part Three: The Domain Name System (DNS) Database"">RFC3403</a>] for a server in a particular realm. These NAPTR records
<span class="grey">Jones, et al. Standards Track [Page 2]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-3" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
provide a mapping from a domain to the DNS Service Locator (SRV)
record [<a href="./rfc2782" title=""A DNS RR for specifying the location of services (DNS SRV)"">RFC2782</a>] or A/AAAA record [<a href="./rfc1035" title=""Domain names - implementation and specification"">RFC1035</a>] [<a href="./rfc3596" title=""DNS Extensions to Support IP Version 6"">RFC3596</a>] for contacting
a server with the specific transport protocol in the NAPTR services
field.
The extended NAPTR usage for Diameter peer discovery defined by this
document is based on the Straightforward-NAPTR (S-NAPTR) Dynamic
Delegation Discovery System (DDDS) application defined in [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>].
This document updates the Diameter peer discovery procedure described
in <a href="./rfc3588#section-5.2">Section 5.2 of [RFC3588]</a> and defines S-NAPTR application service
and application protocol tag values that permit the discovery of
Diameter peers that support a specific Diameter application and
transport protocol.
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Terminology</span>
The Diameter base protocol specification (<a href="./rfc3588#section-1.3">Section 1.3 of [RFC3588]</a>)
and the Straightforward-NAPTR (S-NAPTR) DDDS application (<a href="./rfc3958#section-2.1">Section 2.1
of [RFC3958]</a>) define the terminology used in this document.
<span class="h3"><a class="selflink" id="section-2.1" href="#section-2.1">2.1</a>. Requirements Language</span>
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 [<a href="./rfc2119" title=""Key words for use in RFCs to Indicate Requirement Levels"">RFC2119</a>].
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Extended NAPTR Service Field Format</span>
The NAPTR service field format defined by the S-NAPTR DDDS
application in [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>] follows this Augmented Backus-Naur Form
(ABNF) [<a href="./rfc5234" title=""Augmented BNF for Syntax Specifications: ABNF"">RFC5234</a>]:
service-parms = [ [app-service] *(":" app-protocol)]
app-service = experimental-service / iana-registered-service
app-protocol = experimental-protocol / iana-registered-protocol
experimental-service = "x-" 1*30ALPHANUMSYM
experimental-protocol = "x-" 1*30ALPHANUMSYM
iana-registered-service = ALPHA *31ALPHANUMSYM
iana-registered-protocol = ALPHA *31ALPHANUMSYM
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z
DIGIT = %x30-39 ; 0-9
SYM = %x2B / %x2D / %x2E ; "+" / "-" / "."
ALPHANUMSYM = ALPHA / DIGIT / SYM
; The app-service and app-protocol tags are limited to 32
; characters and must start with an alphabetic character.
; The service-parms are considered case-insensitive.
<span class="grey">Jones, et al. Standards Track [Page 3]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-4" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
This specification refines the "iana-registered-service" tag
definition for the discovery of Diameter agents supporting a specific
Diameter application as defined below.
iana-registered-service =/ aaa-service
aaa-service = "aaa+ap" appln-id
appln-id = 1*10DIGIT
; Application Identifier expressed as
; a decimal integer without leading
; zeros.
The appln-id element is the Application Identifier used to identify a
specific Diameter application. The Diameter Application Identifier
is a 32-bit unsigned integer, and values are allocated by IANA as
defined in [<a href="./rfc3588" title=""Diameter Base Protocol"">RFC3588</a>].
This specification also refines the "iana-registered-protocol" tag
definition for the discovery of Diameter agents supporting a specific
Diameter transport protocol as defined below.
iana-registered-protocol =/ aaa-protocol
aaa-protocol = "diameter." aaa-transport
aaa-transport = "tcp" / "sctp" / "tls.tcp"
The S-NAPTR application protocol tags defined by this specification
MUST NOT be parsed in any way by the querying application or
resolver. The delimiter (".") is present in the tag to improve
readability and does not imply a structure or namespace of any kind.
The choice of delimiter (".") for the application protocol tag
follows the format of existing S-NAPTR application protocol tag
registry entries, but this does not imply that it shares semantics
with any other specifications that create registry entries with the
same format.
The S-NAPTR application service and application protocol tags defined
by this specification are unrelated to the IANA "Service Name and
Transport Protocol Port Number Registry" (see [<a href="./rfc6335" title=""Internet Assigned Numbers Authority (IANA) Procedures for the Management of the Service Name and Transport Protocol Port Number Registry"">RFC6335</a>]).
The maximum length of the NAPTR service field is 256 octets,
including a one-octet length field (see <a href="./rfc3403#section-4.1">Section 4.1 of [RFC3403]</a> and
<a href="./rfc1035#section-3.3">Section 3.3 of [RFC1035]</a>).
<span class="grey">Jones, et al. Standards Track [Page 4]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-5" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
<span class="h3"><a class="selflink" id="section-3.1" href="#section-3.1">3.1</a>. IETF Standards Track Diameter Applications</span>
A Diameter agent MUST be capable of using the extended S-NAPTR
application service tag for dynamic discovery of a Diameter agent
supporting Standards Track applications. Therefore, every IETF
Standards Track Diameter application MUST be associated with a
"aaa-service" tag formatted as defined in this specification and
allocated in accordance with IANA policy (see <a href="#section-7">Section 7</a>).
For example, a NAPTR service field value of:
'aaa+ap6:diameter.sctp'
means that the Diameter node in the SRV or A/AAAA record supports the
Diameter Session Initiation Protocol (SIP) application ('6') and the
Stream Control Transmission Protocol (SCTP) as the transport
protocol.
<span class="h3"><a class="selflink" id="section-3.2" href="#section-3.2">3.2</a>. Vendor-Specific Diameter Applications</span>
S-NAPTR application service and application protocol tag values can
also be used to discover Diameter peers that support a vendor-
specific Diameter application. In this case, the vendor-specific
Diameter application MUST be associated with a "aaa-service" tag
formatted as defined in this specification and allocated in
accordance with IANA policy (see <a href="#section-7">Section 7</a>).
For example, a NAPTR service field value of:
'aaa+ap16777251:diameter.sctp'
means that the Diameter node in the SRV or A/AAAA record supports the
Diameter Third Generation Partnership Project (3GPP) S6a application
('16777251') and SCTP as the transport protocol.
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. Backwards Compatibility</span>
Domain Name System (DNS) administrators SHOULD also provision legacy
NAPTR records [<a href="./rfc3403" title=""Dynamic Delegation Discovery System (DDDS) Part Three: The Domain Name System (DNS) Database"">RFC3403</a>] in the <a href="./rfc3588">RFC 3588</a> style in order to guarantee
backwards compatibility with legacy Diameter peers that are <a href="./rfc3588">RFC 3588</a>
compliant. If the DNS administrator provisions both extended S-NAPTR
records as defined in this specification and legacy <a href="./rfc3588">RFC 3588</a> NAPTR
records, then the extended S-NAPTR records MUST have higher priority
(e.g., lower order and/or preference values) than legacy NAPTR
records.
<span class="grey">Jones, et al. Standards Track [Page 5]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-6" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. Extended NAPTR-Based Diameter Peer Discovery</span>
The Diameter Peer Discovery principles are described in <a href="./rfc3588#section-5.2">Section 5.2
of [RFC3588]</a>. This specification updates the NAPTR query procedure
in the Diameter peer discovery mechanism by allowing the querying
node to determine which applications are supported by resolved
Diameter peers.
The extended-format NAPTR records provide a mapping from a domain to
the SRV record or A/AAAA record for contacting a server supporting a
specific transport protocol and Diameter application. The resource
record will contain an empty regular expression and a replacement
value, which is the SRV record or the A/AAAA record for that
particular transport protocol.
The assumption for this mechanism to work is that the DNS
administrator of the queried domain has first provisioned the DNS
with extended-format NAPTR entries. The steps below replace the
NAPTR query procedure steps in <a href="./rfc3588#section-5.2">Section 5.2 of [RFC3588]</a>.
a. The Diameter implementation performs a NAPTR query for a server in
a particular realm. The Diameter implementation has to know in
advance in which realm to look for a Diameter agent, and in which
Application Identifier it is interested. For example, the realm
could be deduced from the Network Access Identifier (NAI) in the
User-Name attribute-value pair (AVP) or extracted from the
Destination-Realm AVP.
b. If the returned NAPTR service fields contain entries formatted as
"aaa+apX:Y" where "X" indicates the Application Identifier and "Y"
indicates the supported transport protocol(s), the target realm
supports the extended format for NAPTR-based Diameter peer
discovery defined in this document.
If "X" contains the required Application Identifier and "Y"
matches a supported transport protocol, the Diameter
implementation resolves the "replacement" field entry to a
target host using the lookup method appropriate for the "flags"
field.
If "X" does not contain the required Application Identifier or
"Y" does not match a supported transport protocol, the Diameter
implementation abandons the peer discovery.
<span class="grey">Jones, et al. Standards Track [Page 6]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-7" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
c. If the returned NAPTR service fields contain entries formatted as
"aaa+apX" where "X" indicates the Application Identifier, the
target realm supports the extended format for NAPTR-based Diameter
peer discovery defined in this document.
If "X" contains the required Application Identifier, the
Diameter implementation resolves the "replacement" field entry
to a target host using the lookup method appropriate for the
"flags" field and attempts to connect using all supported
transport protocols following the order specified in
<a href="./rfc3588#section-2.1">Section 2.1 of [RFC3588]</a>.
If "X" does not contain the required Application Identifier,
the Diameter implementation abandons the peer discovery.
d. If the returned NAPTR service fields contain entries formatted as
"aaa:X" where "X" indicates the supported transport protocol(s),
the target realm supports Diameter but does not support the
extended format for NAPTR-based Diameter peer discovery defined in
this document.
If "X" matches a supported transport protocol, the Diameter
implementation resolves the "replacement" field entry to a
target host using the lookup method appropriate for the "flags"
field.
e. If the returned NAPTR service fields contain entries formatted as
"aaa", the target realm supports Diameter but does not support the
extended format for NAPTR-based Diameter peer discovery defined in
this document. The Diameter implementation resolves the
"replacement" field entry to a target host using the lookup method
appropriate for the "flags" field and attempts to connect using
all supported transport protocols following the order specified in
<a href="./rfc3588#section-2.1">Section 2.1 of [RFC3588]</a>.
f. If the target realm does not support NAPTR-based Diameter peer
discovery, the client proceeds with the next peer discovery
mechanism described in <a href="./rfc3588#section-5.2">Section 5.2 of [RFC3588]</a>.
<span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>. Examples</span>
As an example, consider a client that wishes to discover a Diameter
server in the ex1.example.com realm that supports the Credit Control
application. The client performs a NAPTR query for that domain, and
the following NAPTR records are returned:
<span class="grey">Jones, et al. Standards Track [Page 7]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-8" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
;; order pref flags service regexp replacement
IN NAPTR 50 50 "s" "aaa:diameter.sctp" ""
_diameter._sctp.ex1.example.com
IN NAPTR 50 50 "s" "aaa+ap1:diameter.sctp" ""
_diameter._sctp.ex1.example.com
IN NAPTR 50 50 "s" "aaa+ap4:diameter.sctp" ""
_diameter._sctp.ex1.example.com
This indicates that the server supports NASREQ (ID=1) and Credit
Control (ID=4) applications over SCTP. If the client supports SCTP,
it will be used, targeted to a host determined by an SRV lookup of
_diameter._sctp.ex1.example.com.
That SRV lookup would return:
;; Priority Weight Port Target
IN SRV 0 1 3868 server1.ex1.example.com
IN SRV 0 2 3868 server2.ex1.example.com
As an alternative example, a client wishes to discover a Diameter
server in the ex2.example.com realm that supports the NASREQ
application over SCTP. The client performs a NAPTR query for that
domain, and the following NAPTR records are returned:
;; order pref flags service regexp replacement
IN NAPTR 150 50 "a" "aaa:diameter.sctp" ""
server1.ex2.example.com
IN NAPTR 150 50 "a" "aaa:diameter.tls.tcp" ""
server2.ex2.example.com
IN NAPTR 150 50 "a" "aaa+ap1:diameter.sctp" ""
server1.ex2.example.com
IN NAPTR 150 50 "a" "aaa+ap1:diameter.tls.tcp" ""
server2.ex2.example.com
This indicates that the server supports NASREQ (ID=1) over SCTP and
Transport Layer Security (TLS)/TCP via hosts server1.ex2.example.com
and server2.ex2.example.com, respectively.
<span class="h2"><a class="selflink" id="section-6" href="#section-6">6</a>. Usage Guidelines</span>
Diameter is a peer-to-peer protocol, whereas most of the applications
that extend the base protocol behave like client/server applications.
The role of the peer is not advertised in the NAPTR tags and not even
communicated during Diameter capability negotiation
(Capabilities-Exchange-Request and Capabilities-Exchange-Answer
message exchange). For this reason, NAPTR-based Diameter peer
discovery for an application defining client/server roles should only
be used by a client to discover servers.
<span class="grey">Jones, et al. Standards Track [Page 8]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-9" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
<span class="h2"><a class="selflink" id="section-7" href="#section-7">7</a>. IANA Considerations</span>
<span class="h3"><a class="selflink" id="section-7.1" href="#section-7.1">7.1</a>. IETF Diameter Application Service Tags</span>
IANA has reserved a value of "aaa" for Diameter in the "(S-NAPTR)
Application Service Tag" registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>]. IANA has
also reserved the following S-NAPTR application service tags for
existing IETF Diameter applications in the same registry.
+------------------+----------------------------+
| Tag | Diameter Application |
+------------------+----------------------------+
| aaa+ap1 | NASREQ [<a href="./rfc3588" title=""Diameter Base Protocol"">RFC3588</a>] |
| aaa+ap2 | Mobile IPv4 [<a href="./rfc4004" title=""Diameter Mobile IPv4 Application"">RFC4004</a>] |
| aaa+ap3 | Base Accounting [<a href="./rfc3588" title=""Diameter Base Protocol"">RFC3588</a>] |
| aaa+ap4 | Credit Control [<a href="./rfc4006" title=""Diameter Credit-Control Application"">RFC4006</a>] |
| aaa+ap5 | EAP [<a href="./rfc4072" title=""Diameter Extensible Authentication Protocol (EAP) Application"">RFC4072</a>] |
| aaa+ap6 | SIP [<a href="./rfc4740" title=""Diameter Session Initiation Protocol (SIP) Application"">RFC4740</a>] |
| aaa+ap7 | Mobile IPv6 IKE [<a href="./rfc5778" title=""Diameter Mobile IPv6: Support for Home Agent to Diameter Server Interaction"">RFC5778</a>] |
| aaa+ap8 | Mobile IPv6 Auth [<a href="./rfc5778" title=""Diameter Mobile IPv6: Support for Home Agent to Diameter Server Interaction"">RFC5778</a>] |
| aaa+ap9 | QoS [<a href="./rfc5866" title=""Diameter Quality-of-Service Application"">RFC5866</a>] |
| aaa+ap4294967295 | Relay [<a href="./rfc3588" title=""Diameter Base Protocol"">RFC3588</a>] |
+------------------+----------------------------+
Future IETF Diameter applications MUST reserve the S-NAPTR
application service tag corresponding to the allocated Diameter
Application ID as defined in <a href="#section-3">Section 3</a>.
<span class="h3"><a class="selflink" id="section-7.2" href="#section-7.2">7.2</a>. 3GPP Diameter Application Service Tags</span>
IANA has reserved the following S-NAPTR application service tags for
existing 3GPP Diameter applications in the "S-NAPTR Application
Service Tag" registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>].
+----------------+----------------------+
| Tag | Diameter Application |
+----------------+----------------------+
| aaa+ap16777250 | 3GPP STa [<a href="#ref-TS29.273" title=""3GPP TS 29.273; Technical Specification Group Core Network and Terminals; Evolved Packet System (EPS); 3GPP EPS AAA interfaces (Release 8)"">TS29.273</a>] |
| aaa+ap16777251 | 3GPP S6a [<a href="#ref-TS29.272" title=""3GPP TS 29.272; Technical Specification Group Core Network and Terminals; Evolved Packet System (EPS); Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) Related Interfaces Based on Diameter Protocol (Release 8)"">TS29.272</a>] |
| aaa+ap16777264 | 3GPP SWm [<a href="#ref-TS29.273" title=""3GPP TS 29.273; Technical Specification Group Core Network and Terminals; Evolved Packet System (EPS); 3GPP EPS AAA interfaces (Release 8)"">TS29.273</a>] |
| aaa+ap16777267 | 3GPP S9 [<a href="#ref-TS29.215" title=""3GPP TS 29.215; Technical Specification Group Core Network and Terminals; Policy and Charging Control (PCC) over S9 reference point; Stage 3 (Release 8)"">TS29.215</a>] |
+----------------+----------------------+
Future 3GPP Diameter applications can reserve entries in the "S-NAPTR
Application Service Tag" registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>] that
correspond to the allocated Diameter Application IDs as defined in
<a href="#section-3">Section 3</a>.
<span class="grey">Jones, et al. Standards Track [Page 9]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-10" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
<span class="h3"><a class="selflink" id="section-7.3" href="#section-7.3">7.3</a>. WiMAX Forum Diameter Application Service Tags</span>
IANA has reserved the following S-NAPTR application service tags for
existing Worldwide Interoperability for Microwave Access (WiMAX)
Forum Diameter applications in the "S-NAPTR Application Service Tag"
registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>].
+----------------+--------------------------------------------------+
| Tag | Diameter Application |
+----------------+--------------------------------------------------+
| aaa+ap16777281 | WiMAX Network Access Authentication and |
| | Authorization Diameter Application (WNAAADA) |
| | [<a href="#ref-WiMAX-BASE" title=""WMF-T33-001-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Base Specification - Release 1.5"">WiMAX-BASE</a>] |
| aaa+ap16777282 | WiMAX Network Accounting Diameter Application |
| | (WNADA) [<a href="#ref-WiMAX-BASE" title=""WMF-T33-001-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Base Specification - Release 1.5"">WiMAX-BASE</a>] |
| aaa+ap16777283 | WiMAX MIP4 Diameter Application (WM4DA) |
| | [<a href="#ref-WiMAX-BASE" title=""WMF-T33-001-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Base Specification - Release 1.5"">WiMAX-BASE</a>] |
| aaa+ap16777284 | WiMAX MIP6 Diameter Application (WM6DA) |
| | [<a href="#ref-WiMAX-BASE" title=""WMF-T33-001-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Base Specification - Release 1.5"">WiMAX-BASE</a>] |
| aaa+ap16777285 | WiMAX DHCP Diameter Application (WDDA) |
| | [<a href="#ref-WiMAX-BASE" title=""WMF-T33-001-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Base Specification - Release 1.5"">WiMAX-BASE</a>] |
| aaa+ap16777286 | WiMAX Location Authentication Authorization |
| | Diameter Application (WLAADA) [<a href="#ref-WiMAX-LBS" title=""WMF-T33-110-R015v01 - WiMAX Forum(R) Network Architecture - Protocols and Procedures for Location Based Services - Release 1.5"">WiMAX-LBS</a>] |
| aaa+ap16777287 | WiMAX Policy and Charging Control R3 Policies |
| | Diameter Application (WiMAX PCC-R3-P) |
| | [<a href="#ref-WiMAX-PCC" title=""WMF-T33-109-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Policy and Charging Control - Release 1.5"">WiMAX-PCC</a>] |
| aaa+ap16777288 | WiMAX Policy and Charging Control R3 Offline |
| | Charging Diameter Application (WiMAX PCC-R3-OFC) |
| | [<a href="#ref-WiMAX-PCC" title=""WMF-T33-109-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Policy and Charging Control - Release 1.5"">WiMAX-PCC</a>] |
| aaa+ap16777289 | WiMAX Policy and Charging Control R3 Offline |
| | Charging Prime Diameter Application (WiMAX |
| | PCC-R3-OFC-PRIME) [<a href="#ref-WiMAX-PCC" title=""WMF-T33-109-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Policy and Charging Control - Release 1.5"">WiMAX-PCC</a>] |
| aaa+ap16777290 | WiMAX Policy and Charging Control R3 Online |
| | Charging Diameter Application (WiMAX PCC-R3-OC) |
| | [<a href="#ref-WiMAX-PCC" title=""WMF-T33-109-R015v02 - WiMAX Forum(R) Network Architecture - Detailed Protocols and Procedures, Policy and Charging Control - Release 1.5"">WiMAX-PCC</a>] |
+----------------+--------------------------------------------------+
Future WiMAX Forum Diameter applications can reserve entries in the
"S-NAPTR Application Service Tag" registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>] that
correspond to the allocated Diameter Application IDs as defined in
<a href="#section-3">Section 3</a>.
<span class="h3"><a class="selflink" id="section-7.4" href="#section-7.4">7.4</a>. Vendor-Specific Diameter Application Service Tags</span>
Vendor-Specific Diameter Application IDs are allocated by IANA
according to the "First Come First Served" policy and do not require
an IETF specification. However, the S-NAPTR application service tag
registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>] defines a registration policy of
<span class="grey">Jones, et al. Standards Track [Page 10]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-11" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
"Specification Required" with a further stipulation that the
"specification" is an RFC (of any category). If a vendor-specific
Diameter application requires the functionality defined in this
document, an RFC of any category MUST be published that reserves the
S-NAPTR Application Service Tag corresponding to the Vendor-Specific
Diameter Application ID as defined in <a href="#section-3">Section 3</a>.
<span class="h3"><a class="selflink" id="section-7.5" href="#section-7.5">7.5</a>. Diameter Application Protocol Tags</span>
IANA has reserved the following S-NAPTR Application Protocol Tags for
the Diameter transport protocols in the "S-NAPTR Application Protocol
Tag" registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>].
+------------------+----------+
| Tag | Protocol |
+------------------+----------+
| diameter.tcp | TCP |
| diameter.sctp | SCTP |
| diameter.tls.tcp | TLS/TCP |
+------------------+----------+
Future Diameter versions that introduce new transport protocols MUST
reserve an appropriate S-NAPTR Application Protocol Tag in the
"S-NAPTR Application Protocol Tag" registry created by [<a href="./rfc3958" title=""Domain-Based Application Service Location Using SRV RRs and the Dynamic Delegation Discovery Service (DDDS)"">RFC3958</a>].
<span class="h2"><a class="selflink" id="section-8" href="#section-8">8</a>. Security Considerations</span>
This document specifies an enhancement to the NAPTR service field
format defined in <a href="./rfc3588">RFC 3588</a> and also modifications to the NAPTR
processing logic defined in <a href="./rfc3588">RFC 3588</a>. The enhancement and
modifications are based on the S-NAPTR, which is actually a
simplification of the NAPTR, and therefore the same security
considerations described in <a href="./rfc3588">RFC 3588</a> [<a href="./rfc3588" title=""Diameter Base Protocol"">RFC3588</a>] are applicable to this
document. No further extensions are required beyond the security
mechanisms offered by <a href="./rfc3588">RFC 3588</a>. However, a malicious host doing
S-NAPTR queries learns applications supported by Diameter agents in a
certain realm faster, which might help the malicious host to scan
potential targets for an attack more efficiently when some
applications have known vulnerabilities.
<span class="h2"><a class="selflink" id="section-9" href="#section-9">9</a>. Acknowledgments</span>
We would like to thank Glen Zorn, Avi Lior, Itsuma Tanaka, Sebastien
Decugis, Dan Romascanu, Adrian Farrel, David Harrington, Pete
Resnick, Robert Sparks, Stephen Farrell, Wesley Eddy, Ralph Droms,
and Joe Touch for their comprehensive review comments.
<span class="grey">Jones, et al. Standards Track [Page 11]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-12" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
<span class="h2"><a class="selflink" id="section-10" href="#section-10">10</a>. References</span>
<span class="h3"><a class="selflink" id="section-10.1" href="#section-10.1">10.1</a>. Normative References</span>
[<a id="ref-RFC1035">RFC1035</a>] Mockapetris, P., "Domain names - implementation and
specification", STD 13, <a href="./rfc1035">RFC 1035</a>, November 1987.
[<a id="ref-RFC2119">RFC2119</a>] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", <a href="https://www.rfc-editor.org/bcp/bcp14">BCP 14</a>, <a href="./rfc2119">RFC 2119</a>, March 1997.
[<a id="ref-RFC2782">RFC2782</a>] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)",
<a href="./rfc2782">RFC 2782</a>, February 2000.
[<a id="ref-RFC3403">RFC3403</a>] Mealling, M., "Dynamic Delegation Discovery System
(DDDS) Part Three: The Domain Name System (DNS)
Database", <a href="./rfc3403">RFC 3403</a>, October 2002.
[<a id="ref-RFC3588">RFC3588</a>] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
Arkko, "Diameter Base Protocol", <a href="./rfc3588">RFC 3588</a>,
September 2003.
[<a id="ref-RFC3596">RFC3596</a>] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
"DNS Extensions to Support IP Version 6", <a href="./rfc3596">RFC 3596</a>,
October 2003.
[<a id="ref-RFC3958">RFC3958</a>] Daigle, L. and A. Newton, "Domain-Based Application
Service Location Using SRV RRs and the Dynamic
Delegation Discovery Service (DDDS)", <a href="./rfc3958">RFC 3958</a>,
January 2005.
[<a id="ref-RFC4004">RFC4004</a>] Calhoun, P., Johansson, T., Perkins, C., Hiller, T.,
Ed., and P. McCann, "Diameter Mobile IPv4 Application",
<a href="./rfc4004">RFC 4004</a>, August 2005.
[<a id="ref-RFC4006">RFC4006</a>] Hakala, H., Mattila, L., Koskinen, J-P., Stura, M., and
J. Loughney, "Diameter Credit-Control Application",
<a href="./rfc4006">RFC 4006</a>, August 2005.
[<a id="ref-RFC4072">RFC4072</a>] Eronen, P., Ed., Hiller, T., and G. Zorn, "Diameter
Extensible Authentication Protocol (EAP) Application",
<a href="./rfc4072">RFC 4072</a>, August 2005.
[<a id="ref-RFC4740">RFC4740</a>] Garcia-Martin, M., Ed., Belinchon, M., Pallares-Lopez,
M., Canales-Valenzuela, C., and K. Tammi, "Diameter
Session Initiation Protocol (SIP) Application",
<a href="./rfc4740">RFC 4740</a>, November 2006.
<span class="grey">Jones, et al. Standards Track [Page 12]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-13" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
[<a id="ref-RFC5234">RFC5234</a>] Crocker, D., Ed., and P. Overell, "Augmented BNF for
Syntax Specifications: ABNF", STD 68, <a href="./rfc5234">RFC 5234</a>,
January 2008.
[<a id="ref-RFC5778">RFC5778</a>] Korhonen, J., Ed., Tschofenig, H., Bournelle, J.,
Giaretta, G., and M. Nakhjiri, "Diameter Mobile IPv6:
Support for Home Agent to Diameter Server Interaction",
<a href="./rfc5778">RFC 5778</a>, February 2010.
[<a id="ref-RFC5866">RFC5866</a>] Sun, D., Ed., McCann, P., Tschofenig, H., Tsou, T.,
Doria, A., and G. Zorn, Ed., "Diameter
Quality-of-Service Application", <a href="./rfc5866">RFC 5866</a>, May 2010.
[<a id="ref-TS29.215">TS29.215</a>] 3rd Generation Partnership Project, "3GPP TS 29.215;
Technical Specification Group Core Network and
Terminals; Policy and Charging Control (PCC) over S9
reference point; Stage 3 (Release 8)",
<<a href="http://www.3gpp.org/ftp/Specs/html-info/29215.htm">http://www.3gpp.org/ftp/Specs/html-info/29215.htm</a>>.
[<a id="ref-TS29.272">TS29.272</a>] 3rd Generation Partnership Project, "3GPP TS 29.272;
Technical Specification Group Core Network and
Terminals; Evolved Packet System (EPS); Mobility
Management Entity (MME) and Serving GPRS Support Node
(SGSN) Related Interfaces Based on Diameter Protocol
(Release 8)",
<<a href="http://www.3gpp.org/ftp/Specs/html-info/29272.htm">http://www.3gpp.org/ftp/Specs/html-info/29272.htm</a>>.
[<a id="ref-TS29.273">TS29.273</a>] 3rd Generation Partnership Project, "3GPP TS 29.273;
Technical Specification Group Core Network and
Terminals; Evolved Packet System (EPS); 3GPP EPS AAA
interfaces (Release 8)",
<<a href="http://www.3gpp.org/ftp/Specs/html-info/29273.htm">http://www.3gpp.org/ftp/Specs/html-info/29273.htm</a>>.
[<a id="ref-WiMAX-BASE">WiMAX-BASE</a>] WiMAX Forum, "WMF-T33-001-R015v02 - WiMAX Forum(R)
Network Architecture - Detailed Protocols and
Procedures, Base Specification - Release 1.5",
<<a href="http://www.wimaxforum.org/resources/documents/technical/T33">http://www.wimaxforum.org/resources/</a>
<a href="http://www.wimaxforum.org/resources/documents/technical/T33">documents/technical/T33</a>>.
[<a id="ref-WiMAX-LBS">WiMAX-LBS</a>] WiMAX Forum, "WMF-T33-110-R015v01 - WiMAX Forum(R)
Network Architecture - Protocols and Procedures for
Location Based Services - Release 1.5",
<<a href="http://www.wimaxforum.org/resources/documents/technical/T33">http://www.wimaxforum.org/resources/</a>
<a href="http://www.wimaxforum.org/resources/documents/technical/T33">documents/technical/T33</a>>.
<span class="grey">Jones, et al. Standards Track [Page 13]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-14" ></span>
<span class="grey"><a href="./rfc6408">RFC 6408</a> Diameter S-NAPTR Usage November 2011</span>
[<a id="ref-WiMAX-PCC">WiMAX-PCC</a>] WiMAX Forum, "WMF-T33-109-R015v02 - WiMAX Forum(R)
Network Architecture - Detailed Protocols and
Procedures, Policy and Charging Control - Release 1.5",
<<a href="http://www.wimaxforum.org/resources/documents/technical/T33">http://www.wimaxforum.org/resources/</a>
<a href="http://www.wimaxforum.org/resources/documents/technical/T33">documents/technical/T33</a>>.
<span class="h3"><a class="selflink" id="section-10.2" href="#section-10.2">10.2</a>. Informative References</span>
[<a id="ref-RFC6335">RFC6335</a>] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and
S. Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", <a href="https://www.rfc-editor.org/bcp/bcp165">BCP 165</a>,
<a href="./rfc6335">RFC 6335</a>, August 2011.
Authors' Addresses
Mark Jones
Bridgewater Systems
EMail: mark@azu.ca
Jouni Korhonen
Nokia Siemens Networks
EMail: jouni.nospam@gmail.com
Lionel Morand
Orange Labs
EMail: lionel.morand@orange.com
Jones, et al. Standards Track [Page 14]
</pre>
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