One document matched: draft-ietf-dime-diameter-qos-14.xml
<?xml version="1.0" encoding="US-ASCII"?>
<?xml-stylesheet type='text/xsl' href='./rfc2629.xslt' ?>
<?rfc toc="yes"?>
<?rfc symrefs="no"?>
<?rfc compact="no" ?>
<?rfc sortrefs="yes" ?>
<?rfc strict="yes" ?>
<?rfc linkmailto="yes" ?>
<!DOCTYPE rfc PUBLIC "-//IETF//DTD RFC 2629//EN"
"http://xml.resource.org/authoring/rfc2629.dtd" [
<!ENTITY RFC2119 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml">
<!ENTITY RFC3588 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3588.xml">
<!ENTITY RFC4005 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4005.xml">
<!ENTITY I-D.ietf-dime-qos-attributes SYSTEM "http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-dime-qos-attributes.xml">
<!ENTITY I-D.ietf-nsis-ntlp SYSTEM "http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-nsis-ntlp.xml">
<!ENTITY RFC5624 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5624.xml">
<!ENTITY I-D.ietf-nsis-qos-nslp SYSTEM "http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-nsis-qos-nslp.xml">
<!ENTITY RFC4566 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4566.xml">
<!ENTITY RFC2211 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2211.xml">
<!ENTITY RFC2212 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2212.xml">
<!ENTITY RFC2205 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2205.xml">
<!ENTITY RFC2753 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2753.xml">
<!ENTITY RFC2865 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2865.xml">
<!ENTITY RFC3521 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3521.xml">
<!ENTITY RFC3313 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3313.xml">
<!ENTITY RFC3520 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3520.xml">
<!ENTITY RFC2474 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.2474.xml">
<!ENTITY RFC5246 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.5246.xml">
<!ENTITY RFC4282 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.4282.xml">
<!ENTITY RFC3261 SYSTEM "http://xml.resource.org/public/rfc/bibxml/reference.RFC.3261.xml">
]>
<?xml-stylesheet type='text/xsl' href='./rfc2629.xslt' ?>
<?rfc toc="yes"?>
<?rfc symrefs="yes"?>
<?rfc strict="no"?>
<?rfc compact="no" ?>
<?rfc subcompact="yes" ?>
<?rfc sortrefs="yes" ?>
<rfc category="std" docName="draft-ietf-dime-diameter-qos-14.txt"
ipr="trust200902">
<front>
<title abbrev="Diameter QoS Application">Diameter Quality of Service
Application</title>
<author fullname="Dong Sun" initials="D." role="editor" surname="Sun">
<organization>Alcatel-Lucent</organization>
<address>
<postal>
<street>600 Mountain Ave</street>
<street></street>
<city>Murray Hill</city>
<region>NJ</region>
<code>07974</code>
<country>USA</country>
</postal>
<phone>+1 908 582 2617</phone>
<email>d.sun@alcatel-lucent.com</email>
</address>
</author>
<author fullname="Peter J. McCann" initials="P." surname="McCann">
<organization abbrev="Motorola Labs">Motorola Labs</organization>
<address>
<postal>
<street>1301 E. Algonquin Rd</street>
<city>Schaumburg</city>
<region>IL</region>
<code>60196</code>
<country>USA</country>
</postal>
<phone>+1 847 576 3440</phone>
<email>pete.mccann@motorola.com</email>
</address>
</author>
<author fullname="Hannes Tschofenig" initials="H." surname="Tschofenig">
<organization>Nokia Siemens Networks</organization>
<address>
<postal>
<street>Linnoitustie 6</street>
<city>Espoo</city>
<code>02600</code>
<country>Finland</country>
</postal>
<phone>+358 (50) 4871445</phone>
<email>Hannes.Tschofenig@gmx.net</email>
<uri>http://www.tschofenig.priv.at</uri>
</address>
</author>
<author fullname="Tina Tsou" initials="T." surname="Tsou">
<organization abbrev="Huawei">Huawei</organization>
<address>
<postal>
<street></street>
<city>Shenzhen</city>
<region></region>
<code></code>
<country>P.R.C</country>
</postal>
<email>tena@huawei.com</email>
</address>
</author>
<author fullname="Avri Doria" initials="A." surname="Doria">
<organization abbrev="Lulea University of Technology">Lulea University
of Technology</organization>
<address>
<postal>
<street>Arbetsvetenskap</street>
<city>Lulea</city>
<region></region>
<code>SE-97187</code>
<country>Sweden</country>
</postal>
<email>avri@ltu.se</email>
</address>
</author>
<author fullname="Glen Zorn" initials="G.Z." role="editor" surname="Zorn">
<organization>Network Zen</organization>
<address>
<postal>
<street>1310 East Thomas Street</street>
<street>#306</street>
<city>Seattle</city>
<region>Washington</region>
<code>98102</code>
<country>USA</country>
</postal>
<phone>+1 (206) 377-9035</phone>
<email>gwz@net-zen.net</email>
</address>
</author>
<date year="2010" />
<area>Operations and Management</area>
<workgroup>Diameter Maintenance and Extensions (DIME)</workgroup>
<keyword>Diameter</keyword>
<keyword>AAA</keyword>
<keyword>QoS</keyword>
<keyword>Policy</keyword>
<keyword>VoIP</keyword>
<keyword>SIP</keyword>
<abstract>
<t> This document describes the framework, messages and procedures for
the Diameter Quality of Service (QoS) application. The Diameter QoS
application allows network elements to interact with Diameter servers
when allocating QoS resources in the network. In particular, two
modes of operation, namely "Pull" and "Push", are defined.</t>
</abstract>
</front>
<middle>
<!-- ====================================================================== -->
<section anchor="introduction" title="Introduction">
<t>This document describes the framework, messages and procedures for
the Diameter <xref target="RFC3588"> </xref> Quality of Service (QoS)
application. The Diameter QoS application allows Network Elements (NEs)
to interact with Diameter servers when allocating QoS resources in the
network.</t>
<t>Two modes of operation are defined. In the first, called "Pull" mode,
the network element requests QoS authorization from the Diameter server
based on some trigger (such as a QoS signaling protocol) that arrives
along the data path. In the second, called "Push" mode, the Diameter
server pro-actively sends a command to the network element(s) to install
QoS authorization state. This could be triggered, for instance, by
off-path signaling, such as Session Initiation Protocol (SIP) <xref
target="RFC3261"></xref> call control.</t>
<t>A set of command codes is specified that allows a single Diameter QoS
application server to support both Pull and Push modes based on the
requirements of network technologies, deployment scenarios and end-host
capabilities. In conjunction with Diameter AVPs defined in <xref
target="I-D.ietf-dime-qos-attributes"></xref> and in <xref
target="RFC5624"></xref>, this document depicts
basic call flow procedures used to establish, modify and terminate a
Diameter QoS application session.</t>
<t>This document defines a number of Diameter-encoded Attribute Value Pairs
(AVPs), which are described using a modified version of the Augmented
Backus-Naur Form (ABNF), see <xref target="RFC3588"/>.</t>
</section>
<!-- ====================================================================== -->
<section 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 RFC 2119 <xref
target="RFC2119"></xref>.</t>
<t>The following terms are used in this document:</t>
<t><list style="hanging">
<t hangText="AAA Cloud"><vspace blankLines="0" /> An infrastructure
of Authentication, Authorization and Accounting (AAA) entities
(clients, agents, servers) communicating via a AAA protocol over
trusted, secure connections. It offers authentication, authorization
and accounting services to applications in local and
roaming scenarios. Diameter and RADIUS <xref
target="RFC2865"></xref> are both widely deployed AAA protocols.
<vspace blankLines="1" /></t>
<t hangText="Application Endpoint (AppE)"><vspace blankLines="0" />
An Application Endpoint is an entity in an end-user device that
exchanges signaling messages with Application Servers or
directly with other Application Endpoints. Based on the result of
this signaling, the Endpoint may make a request for QoS from the
network. For example, a SIP User Agent is one kind of Application
Endpoint. <vspace blankLines="1" /></t>
<t hangText="Application Server (AppS)"><vspace blankLines="0" /> An
Application Server is an entity that exchanges signaling messages
with an Application Endpoint (see above). It may be a source of
authorization for QoS-enhanced application flows. For example, a SIP
server is one kind of Application Server.<vspace
blankLines="1" /></t>
<t hangText="Authorizing Entity (AE)"><vspace blankLines="0" /> The
Authorizing Entity is a Diameter server that supports the QoS
application. It is responsible for authorizing QoS requests for a
particular application flow or aggregate. The Authorizing Entity may
be a standalone entity or may be integrated with an Application
Server and may be co-located with a subscriber database. This entity
corresponds to the Policy Decision Point (PDP) <xref
target="RFC2753"></xref>.<vspace blankLines="1" /></t>
<t hangText="Network Element (NE)"><vspace blankLines="0" /> A QoS
aware router that acts as a Diameter client for the QoS application.
This entity triggers the protocol interaction for the Pull mode, and
it is the recipient of QoS information in the Push mode. The
Diameter Client at an Network Element corresponds to the Policy
Enforcement Point (PEP) <xref target="RFC2753"></xref>.<vspace
blankLines="1" /></t>
<t hangText="Pull Mode"><vspace blankLines="0" />In this mode, the
QoS authorization process is invoked by the QoS reservation request
received from the Application Endpoint. The Network Element then
requests the QoS authorization decision from the Authorizing
Entity.<vspace blankLines="1" /></t>
<t hangText="Push Mode"><vspace blankLines="0" />In this mode, the
QoS authorization process is invoked by the request from Application
Server or local policies in the Authorizing Entity. The Authorizing
Entity then installs the QoS authorization decision to the Network
Element directly. <vspace blankLines="1" /></t>
<t hangText="Resource Requesting Entity (RRE)"><vspace
blankLines="0" /> A Resource Requesting Entity is a logical entity
that supports the protocol interaction for QoS resources. The RRE
resides in the end-host and is able to communicate with peer logical
entities in an Authorizing Entity or a Network Element to trigger
the QoS authorization process.<vspace blankLines="1" /></t>
</list></t>
</section>
<!-- ====================================================================== -->
<section anchor="architecture" title="Framework">
<t>The Diameter QoS application runs between a NE (acting as a Diameter
client) and the resource AE (acting as a Diameter server). A high-level
picture of the resulting architecture is shown in <xref
target="fig-qos-aaa"></xref>.</t>
<t><figure anchor="fig-qos-aaa"
title="An Architecture Supporting QoS-AAA">
<artwork><![CDATA[
+-------+---------+
| Authorizing |
| Entity |
|(Diameter Server)|
+-------+---------+
|
|
/\-----+-----/\
//// \\\\
|| AAA Cloud ||
| (Diameter application) |
|| ||
\\\\ ////
\-------+-----/
|
+---+--+ +-----+----+ +---+--+
| | | NE | | | Media
+ NE +===+(Diameter +===+ NE +=============>>
| | | Client) | | | Flow
+------+ +----------+ +------+
]]></artwork>
</figure></t>
<t><xref target="fig-qos-aaa"></xref> depicts NEs through which media
flows need to pass, a cloud of AAA servers, and an AE. Note that there
may be more than one router that needs to interact with the AAA cloud
along the path of a given application flow, although the figure only
depicts one for clarity.</t>
<t>In some deployment scenarios, NEs may request authorization through
the AAA cloud based on an incoming QoS reservation request. The NE will
route the request to a designated AE. The AE will return the result of
the authorization decision. In other deployment scenarios, the
authorization will be initiated upon dynamic application state, so that
the request must be authenticated and authorized based on information
from one or more AppSs. After receiving the authorization request from
the AppS or the NE, the AE decides the appropriate mode (i.e., Push or
Pull). The usage Push or Pull mode can be determined by the authorizing
entity either statically or dynamically. Static determination might be
based on a configurable defined policy in the authorizing entity, while
dynamic determination might be based on information received from an
application server. For Push mode, the authorizing entity needs to
identify the appropriate NE(s) to which QoS authorization information
needs to be pushed. It might determine this based on information
received from the AppS, such as the IP addresses of media flows.</t>
<t>In some deployment scenarios, there is a mapping between access
network type and the service logic (e.g., selection of the Push or Pull
mode, and other differentiated handling of the resource admission and
control). The access network type might be derived from the
authorization request from the AppS or the NE, and in this case, the
authorizing entity can identify the corresponding service logic based on
the mapping.</t>
<t>If the interface between the NEs and the AAA cloud is identical
regardless of whether the AE communicates with an AppS or not, routers
are insulated from the details of particular applications and need not
know that Application Servers are involved. Also, the AAA cloud may also
encompass business relationships such as those between network operators
and third-party application providers. This enables flexible intra- or
inter-domain authorization, accounting, and settlement.</t>
<section anchor="router_model" title="Network Element Functional Model">
<t><xref target="fig-ne-model"></xref> depicts a logical operational
model of resource management in a router.</t>
<t><figure anchor="fig-ne-model"
title="Network Element Functional Model">
<artwork><![CDATA[
+-------------------------------------------------------+
| DIAMETER Client |
| Functionality |
| +---------------++-----------------++---------------+ |
| | User || QoS Application || Accounting | |
| | Authentication|| Client || Client (e.g., | |
| | Client || (Authorization ||for QoS Traffic| |
| +---------------+| of QoS Requests)|+---------------+ |
| +-----------------+ |
+-------------------------------------------------------+
^
v
+--------------+ +----------+
|QoS Signaling | | Resource |
|Msg Processing|<<<<<>>>>>>>|Management|
+--------------+ +----------+
. ^ | * ^
| v . * ^
+-------------+ * ^
|Signaling msg| * ^
| Processing | * V
+-------------+ * V
| | * V
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
. . * V
| | * .............................
. . * . Traffic Control .
| | * . +---------+.
. . * . |Admission|.
| | * . | Control |.
+----------+ +------------+ . +---------+.
<.->| Input | | Outgoing |<.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.->
| Packet | | Interface | .+----------+ +---------+.
===>|Processing|====| Selection |===.| Packet |====| Packet |.=>
| | |(Forwarding)| .|Classifier| Scheduler|.
+----------+ +------------+ .+----------+ +---------+.
.............................
<.-.-> = signaling flow
=====> = data flow (sender --> receiver)
<<<>>> = control and configuration operations
****** = routing table manipulation
]]></artwork>
</figure></t>
<t>Processing of incoming QoS reservation requests includes three
actions: admission control, authorization and resource
reservation.</t>
<t>The admission control function provides information about available
resources and determines whether there are enough resources to fulfill
the request. Authorization is performed by the Diameter client, which
involves contacting an authorization entity through the AAA cloud
shown in <xref target="architecture"></xref>. If both checks are
successful, the authorized QoS parameters are set in the packet
classifier and the packet scheduler. Note that the parameters passed
to the Traffic Control function may be different from the ones
requested QoS (depending on the authorization decision). Once the
requested resource is granted, the Resource Management function
provides accounting information to the AE via the Diameter client.</t>
</section>
<!-- ====================================================================== -->
<section anchor="Implication"
title="Implications of Endpoint QoS Capabilities">
<t></t>
<section anchor="Categories" title="Endpoint Categories">
<t>The QoS capabilities of Application Endpoints are varied, and can
be categorized as follows: <vspace blankLines="1" /> <list
style="hanging">
<t hangText="Category 1"><vspace blankLines="0" /> A Category 1
Application Endpoint has no QoS capability at either the
application or the network level. This type of AppE may set up a
connection through application signaling, but it is incapable of
specifying resource/QoS requirements through either application
or network-level signaling. <vspace blankLines="1" /></t>
<t hangText="Category 2"><vspace blankLines="0" /> A Category 2
Application Endpoint only has QoS capability at the application
level. This type of AppE is able to set up a connection through
application signaling with certain resource/QoS requirements
(e.g., application attributes), but it is unable to signal any
resource/QoS requirements at the network level. <vspace
blankLines="1" /></t>
<t hangText="Category 3"><vspace blankLines="0" /> A Category 3
Application Endpoint has QoS capability at the network level.
This type of AppE may set up a connection through application
signaling, translate service characteristics into network
resource/QoS requirements (e.g., network QoS class) locally, and
request the resources through network signaling, e.g., Resource
ReSerVation Protocol (RSVP) <xref target="RFC2205"></xref> or
NSIS <xref target="I-D.ietf-nsis-qos-nslp"></xref>.</t>
</list></t>
</section>
<section title="Interaction Modes Between the Authorizing Entity and Network Element">
<t>Different QoS mechanisms are employed in packet networks. Those
QoS mechanisms can be categorized into two schemes: IntServ <xref
target="RFC2211"></xref>, <xref target="RFC2212"></xref> and
DiffServ <xref target="RFC2474"></xref>. In the IntServ scheme,
network signaling (e.g., RSVP, NSIS, or link specific signaling) is
commonly used to initiate a request from an AppE for the desired QoS
resource. In the DiffServ scheme, QoS resources are provisioned
based upon some predefined QoS service classes rather than
AppE-initiated, flow-based QoS requests.</t>
<t>It is obvious that the eligible QoS scheme is correlated to the
AppE's capability in the context of QoS authorization. Since
Category 1 and 2 AppEs cannot initiate the QoS resource requests by
means of network signaling, using the current mechanism of IntServ
model to signal QoS information across the network is not applicable
to them in general. Depending on network technology and operator
requirements, a Category 3 AppE may either make use of network
signaling for resource requests or not.</t>
<t>The diversity of QoS capabilities of endpoints and QoS schemes of
network technology leads to the distinction on the interaction mode
between QoS authorization system and underlying NEs. When the
IntServ scheme is employed by a Category 3 endpoint, the
authorization process is typically initiated by a NE when a trigger
is received from the endpoint such as network QoS signaling. In the
DiffServ scheme, since the NE is unable to request the resource
authorization on its own initiative, the authorization process is
typically triggered by either the request of AppSs or policies
defined by the operator.</t>
<t>As a consequence, two interaction modes are needed in support of
different combinations of QoS schemes and endpoint’s QoS
capabilities: Push mode and Pull mode.</t>
<t><list style="hanging">
<t hangText="Push mode"><vspace blankLines="0" /> The QoS
authorization process is triggered by AppSs or local network
conditions (e.g., time of day on resource usage and QoS
classes), and the authorization decisions are installed by the
AE to the network element on its own initiative without explicit
request. In order to support the push mode, the AE (i.e.,
Diameter server) should be able to initiate a Diameter
authorization session to communicate with the NE (i.e., Diameter
client) without any pre-established connection from the network
element. <vspace blankLines="1" /></t>
<t hangText="Pull mode"><vspace blankLines="0" /> The QoS
authorization process is triggered by the network signaling
received from end-user equipment or by a local event in the NE
according to pre-configured policies, and authorization
decisions are produced upon the request of the NE. In order to
support the pull mode, the NE (i.e., Diameter client) will
initiate a Diameter authorization session to communicate with
the authorizing entity (i.e., Diameter server).</t>
</list></t>
<t>For Category 1 and 2 Application Endpoints, Push mode is
REQUIRED. For a Category 3 AppE, either Push mode or Pull mode MAY
be used.</t>
<t>Push mode is applicable to certain networks, for example, Cable
network, DSL, Ethernet, and Diffserv-enabled IP/MPLS. The Pull mode
is more appropriate to IntServ-enabled IP networks or certain
wireless networks such as the GPRS networks defined by 3GPP. Some
networks (for example, WiMAX) may require both Push and Pull
modes.</t>
</section>
</section>
<section title="Authorization Schemes">
<t></t>
<section anchor="authz_models" title="Pull Mode Schemes">
<t>Three types of basic authorization schemes for Pull mode exist:
one type of two-party scheme and two types of three-party schemes.
The notation adopted here is in respect to the entity that performs
the QoS authorization (QoS Authz). The authentication of the QoS
requesting entity might be done at the NE as part of the QoS
signaling protocol, or by an off-path protocol (on the application
layer or for network access authentication) or the AE might be
contacted with request for authentication and authorization of the
QoS requesting entity. From the Diameter QoS application's point of
view these schemes differ in type of information that need to be
carried. Here we focus on the 'Basic Three Party Scheme' (see <xref
target="fig-three-party-approach"></xref>) and the 'Token-based
Three Party Scheme' (see <xref
target="fig-three-party-token-approach"></xref>). In the 'Two Party
Scheme', the QoS RRE is authenticated by the NE and the
authorization decision is made either locally at the NE itself or
offloaded to a trusted entity (most likely within the same
administrative domain). In the two-party case no Diameter QoS
protocol interaction is required.</t>
<t><figure anchor="fig-three-party-approach"
title="Three Party Scheme">
<artwork><![CDATA[
+--------------+
| Authorizing |
| Entity |
| authorizing | <......+
| resource | .
| request | .
+------------+-+ .
--^----------|-- . .
///// | | \\\\\ .
// | | \\ .
| QoS | QoS AAA | QoS |.
| authz| protocol |authz |.
| req.| | res. |.
\\ | | // .
\\\\\ | | ///// .
QoS --|----------v-- . .
+-------------+ request +-+------------+ .
| Entity |----------------->| NE | .
| requesting | | performing | .
| resource |granted / rejected| QoS | <.....+
| |<-----------------| reservation | financial
+-------------+ +--------------+ settlement
]]></artwork>
</figure></t>
<t>In the 'Basic Three Party Scheme' a QoS reservation request that
arrives at the NE is forwarded to the Authorizing Entity (e.g., in
the user's home network), where the authorization decision is made.
As shown, financial settlement - a business relationship, such as a
roaming agreement, between the visited network and the home network
ensures that the visited network is compensated for the resources
consumed by the user via the home network.</t>
<t><figure anchor="fig-three-party-token-approach"
title="Token-based Three Party Scheme">
<artwork><![CDATA[
financial settlement
...........................+
Authorization V ------- .
Token Request +--------------+ / QoS AAA \ .
+-------------->| | / protocol \ .
| | Authorizing +--------------+ \ .
| | Entity | | | | .
| +------+ |<--+----+ | | .
| | +--------------+ |QoS | |QoS |.
| | |authz| |authz|.
| |Authorization |req.+| |res. |.
| |Token |Token| | |.
| | | | | . | .
| | \ | | . / .
| | \ | | / .
| | QoS request |-----V . .
+-------------+ + Authz. Token +--------+-----+ .
| Entity |----------------->| NE | .
| requesting | | performing | .
| resource |granted / rejected| QoS | <....+
| |<-----------------| reservation |
+-------------+ +--------------+
]]></artwork>
</figure></t>
<t>The 'Token-based Three Party Scheme' is applicable to
environments where a previous protocol interaction is used to
request authorization tokens to assist the authorization process at
the NE or the AE <xref target="RFC3521"></xref>.</t>
<t>The QoS RRE may be involved in an application layer protocol
interaction, for example using SIP <xref target="RFC3313"></xref>,
with the AE. As part of this interaction, authentication and
authorization at the application layer might take place. As a result
of a successful authorization decision, which might involve the
user's home AAA server, an authorization token is generated by the
AE (e.g., the SIP proxy and an entity trusted by the SIP proxy) and
returned to the end host for inclusion into the QoS signaling
protocol. The authorization token will be used by a NE that receives
the QoS signaling message to authorize the QoS request.
Alternatively, the Diameter QoS application will be used to forward
the authorization token to the user's home network. The
authorization token allows that the authorization decision performed
at the application layer can be associated with a corresponding QoS
signaling session. Note that the authorization token might either
refer to established state concerning the authorization decision or
the token might itself carry the authorized parameters (protected by
a digital signature or a keyed message digest to prevent tampering).
In the latter case the authorization token may contain several
pieces of information pertaining to the authorized application
session, but at minimum it should contain: <list style="symbols">
<t>An identifier for the AE (for example, an AppS) that issued
the authorization token</t>
<t>An identifier referring to a specific application protocol
session for which the token was issued and</t>
<t>A keyed message digest or digital signature protecting the
content of the authorization token</t>
</list></t>
<t>A possible structure for the authorization token and the policy
element carrying it are proposed in context of RSVP <xref
target="RFC3520"></xref>.</t>
<t>In the scenario mentioned above, where the QoS resource
requesting entity is involved in an application layer protocol
interaction with the AE, it may be worthwhile to consider a
token-less binding mechanism also. The application layer protocol
interaction may have indicated the transport port numbers at the QoS
RRE where it might receive media streams (for example in SIP/SDP
<xref target="RFC4566"></xref> signalling, these port numbers are
advertised). The QoS RRE may also use these port numbers in some IP
filter indications to the NE performing QoS reservation so that it
may properly tunnel the inbound packets. The NE performing QoS
reservation will forward the QoS resource requesting entity's IP
address and the IP filter indications to the AE in the QoS
authorization request. The AE will use the QoS RRE's IP address and
the port numbers in the IP filter indication, which will match the
port numbers advertised in the earlier application layer protocol
interaction, to identify the right piece of policy information to be
sent to the NE performing the QoS reservation in the QoS
Authorization. response.</t>
</section>
<section title="Push Mode Schemes">
<t>The push mode can be further divided into two types:
endpoint-initiated and network-initiated. In the former case, the
authorization process is triggered by AppS in response to an
explicit QoS request from an endpoint through application signaling,
e.g., SIP; in the latter case, the authorization process is triggered
by the AppS without an explicit QoS request from an endpoint.</t>
<t>In the endpoint-initiated scheme, the QoS RRE (i.e., the AppE)
determines the required application level QoS and sends a QoS
request through an application signaling message. The AppS will
extract application-level QoS information and trigger the
authorization process to the AE. In the network-initiated scheme,
the AE and/or AppS should derive and determine the QoS requirements
according to application attribute, subscription and endpoint's
capability when the endpoint does not explicitly indicate the QoS
attributes. The AE makes an authorization decision based on
application level QoS information, network policies, end-user
subscription, network resource availability, etc., and installs the
decision to NE directly.</t>
<t>A Category 1 AppE requires network-initiated Push mode and a
Category 2 AppE may use either type of Push Mode.</t>
<t><figure anchor="fig-three-party-push-approach"
title="Scheme for Push Mode">
<artwork><![CDATA[
financial settlement
...........................+
Application V ------- .
signaling msg +--------------+ / QoS AAA \ .
+-------------->| | / protocol \ .
| | Authorizing +--------------+ \ .
| | Entity | | | | .
| + |<--+----+ | | .
| +--------------+ |QoS | |QoS |.
| install| |install
| |rsp. | |req. |.
| | | | |.
| | | | . | .
| \ | | . / .
| \ | | / .
V |-----V . .
+-------------+ +--------+-----+ .
| Entity | | NE | .
| requesting | | performing | .
| resource |QoS rsrc granted | QoS | <....+
| |<-----------------| reservation |
+-------------+ +--------------+
]]></artwork>
</figure></t>
</section>
</section>
<!-- ====================================================================== -->
<section title="QoS Application Requirements">
<t>A QoS application must meet a number of requirements applicable to
a diverse set of networking environments and services. It should be
compatible with different deployment scenarios having specific QoS
signaling models and security issues. Satisfying the requirements
listed below while interworking with QoS signaling protocols, a
Diameter QoS application should accommodate the capabilities of the
QoS signaling protocols rather than introducing functional
requirements on them. A list of requirements for a QoS authorization
application is provided here:</t>
<t><list style="hanging">
<t hangText="Identity-based Routing"><vspace blankLines="0" /> The
Diameter QoS application MUST route AAA requests to the
Authorizing Entity, based on the provided identity of the QoS
requesting entity or the identity of the AE encoded in the
provided authorization token.<vspace blankLines="1" /></t>
<t hangText="Flexible Authentication Support"><vspace
blankLines="0" /> The Diameter QoS application MUST support a
variety of different authentication protocols for verification of
authentication information present in QoS signaling messages. The
support for these protocols MAY be provided indirectly by tying
the signaling communication for QoS to a previous authentication
protocol exchange (e.g., using network access
authentication).<vspace blankLines="1" /></t>
<t hangText="Making an Authorization Decision"><vspace
blankLines="0" /> The Diameter QoS application MUST exchange
sufficient information between the AE and the enforcing entity
(and vice versa) to compute an authorization decision and to
execute this decision.<vspace blankLines="1" /></t>
<t hangText="Triggering an Authorization Process"><vspace
blankLines="0" /> The Diameter QoS application MUST allow periodic
and event triggered execution of the authorization process,
originated at the enforcing entity or even at the AE.<vspace
blankLines="1" /></t>
<t
hangText="Associating QoS Reservations and Application State"><vspace
blankLines="0" /> The Diameter QoS application MUST carry
information sufficient for an AppS to identify the appropriate
application session and associate it with a particular QoS
reservation.<vspace blankLines="1" /></t>
<t hangText="Dynamic Authorization"><vspace blankLines="0" /> It
MUST be possible for the Diameter QoS application to push updates
towards the NE(s) from authorizing entities.<vspace
blankLines="1" /></t>
<t hangText="Bearer Gating"><vspace blankLines="0" /> The Diameter
QoS application MUST allow the AE to gate (i.e., enable/disable)
authorized application flows based on, e.g., application state
transitions.<vspace blankLines="1" /></t>
<t hangText="Accounting Records"><vspace blankLines="0" /> The
Diameter QoS application MAY define QoS accounting records
containing duration, volume (byte count) usage information and
description of the QoS attributes (e.g., bandwidth, delay, loss
rate) that were supported for the flow.<vspace
blankLines="1" /></t>
<t hangText="Sending Accounting Records"><vspace blankLines="0" />
The NE SHOULD be able to send accounting records for a particular
QoS reservation state to an accounting entity.<vspace
blankLines="1" /></t>
<t hangText="Failure Notification"><vspace blankLines="0" /> The
Diameter QoS application MUST allow the NE to report failures,
such as loss of connectivity due to movement of a mobile node or
other reasons for packet loss, to the authorizing entity.<vspace
blankLines="1" /></t>
<t hangText="Accounting Correlation"><vspace blankLines="0" /> The
Diameter QoS application MAY support the exchange of sufficient
information to allow for correlation between accounting records
generated by the NEs and accounting records generated by an
AppS.<vspace blankLines="1" /></t>
<t hangText="Interaction with other AAA Applications"><vspace
blankLines="0" /> Interaction with other AAA applications, such as the
Diameter Network Access (NASREQ) application <xref
target="RFC4005"></xref>, may be required for exchange of
authorization, authentication and accounting information.<vspace
blankLines="1" /></t>
</list></t>
<t>In deployment scenarios where authentication of the QoS reservation
requesting entity (e.g., the user) is done by means outside the
Diameter QoS application protocol interaction, the AE is contacted
only with a request for QoS authorization. Authentication might have
taken place already via the interaction with the Diameter NASREQ
application or as part of the QoS signaling protocol (e.g., Transport
Layer Security (TLS) <xref target="RFC5246"></xref> in the General
Internet Signaling Transport (GIST) protocol <xref
target="I-D.ietf-nsis-ntlp"></xref>).</t>
<t>Authentication of the QoS reservation requesting entity to the AE
is necessary if a particular Diameter QoS application protocol cannot
be related (or if there is no intention to relate it) to a prior
authentication. In this case the AE MUST authenticate the QoS
reservation requesting entity in order to authorize the QoS request as
part of the Diameter QoS protocol interaction.</t>
<t>The document refers to three types of sessions that need to be
properly correlated.</t>
<t><list style="hanging">
<t hangText="QoS Signaling Session"><vspace blankLines="0" /> The
time period during which a QoS signaling protocol establishes,
maintains and deletes a QoS reservation state at the QoS network
element is referred to as QoS signaling session. Different QoS
signaling protocols use different ways to identify QoS signaling
sessions. The same applies to different usage environments.
Currently, this document supports three types of QoS session
identifiers, namely a signaling session id (e.g., the Session
Identifier used by the NSIS protocol suite), a flow id (e.g.,
identifier assigned by an application to a certain flow as used in
the 3GPP) and a flow description based on the IP parameters of the
flow's end points.<vspace blankLines="1" /></t>
<t hangText="Diameter Authorization Session"><vspace
blankLines="0" /> The time period, for which a Diameter server
authorizes a requested service (i.e., QoS resource reservation) is
referred to as a Diameter authorization session. It is identified
by a Session-Id included in all Diameter messages used for
management of the authorized service (initial authorization,
re-authorization, termination), see <xref
target="RFC3588"></xref>.<vspace blankLines="1" /></t>
<t hangText="Application-layer Session"><vspace blankLines="0" />
The application layer session identifies the duration of an
application layer service which requires provision of certain QoS.
An application layer session identifier is provided by the QoS
requesting entity in the QoS signaling messages, for example as
part of the authorization token. In general, the application
session identifier is opaque to the QoS aware NEs. It is included
in the authorization request message sent to the AE and helps it
to correlate the QoS authorization request to the application
session state information. <vspace blankLines="1" /></t>
</list></t>
<t>Correlating these sessions is done at each of the three involved
entities: The QoS requesting entity correlates the application with
the QoS signaling sessions. The QoS NE correlates the QoS signaling
session with the Diameter authorization sessions. The AE SHOULD bind
the information about the three sessions together. Note that in
certain scenarios not all of the sessions are present. For example,
the application session might not be visible to QoS signaling protocol
directly if there is no binding between the application session and
the QoS requesting entity using the QoS signaling protocol.</t>
</section>
</section>
<!-- ====================================================================== -->
<section title="QoS Application Session Establishment and Management">
<section title="Parties Involved">
<t>Authorization models supported by this application include three
parties: <list style="symbols">
<t>Resource Requesting Entity</t>
<t>Network Elements (Diameter QoS application (DQA) client)</t>
<t>Authorizing Entity (Diameter QoS application (DQA) server)</t>
</list></t>
<t>Note that the QoS RRE is only indirectly involved in the message
exchange. This entity provides the trigger to initiate the Diameter
QoS protocol interaction by transmitting QoS signaling messages. The
Diameter QoS application is only executed between the Network Element
(i.e., DQA client) and the Authorizing Entity (i.e., DQA server).</t>
<t>The QoS RRE may communicate with the AE using application layer
signaling for negotiation of service parameters. As part of this
application layer protocol interaction, for example using SIP,
authentication and authorization might take place. This message
exchange is, however, outside the scope of this document. The protocol
communication between the QoS resource requesting entity and the QoS
NE might be accomplished using the NSIS protocol suite, RSVP or a link
layer signaling protocol. A description of these protocols is also
outside the scope of this document.</t>
</section>
<section title="Session Establishment">
<t>The Pull and Push modes use a different set of command codes for
session establishment. For other operations, such as session
modification and termination, they use the same set of command
codes.</t>
<t>The selection of Pull mode or Push mode operation is based on the
trigger of the QoS Authorization session. When a
QoS-Authorization-Request (QAR, see <xref target="QAR"></xref>)
message with a new session ID is received, the AE operates in the Pull
mode; when other triggers are received, the AE operates in the Push
mode. Similarly, when a QoS-Install-Request (QIR, see <xref
target="QIR"></xref>} with a new session ID is received, the NE
operates in the Push mode; when other triggers are received, the NE
operation in the Pull mode.</t>
<t>The QoS authorization session is typically established per
subscriber base (i.e., all requests with the same user ID), but it is
also possible to be established on per node or per request base. The
concurrent sessions between an NE and an AE are identified by
different Session-ID.</t>
<section title="Session Establishment for Pull Mode">
<t>A request for a QoS reservation or local events received by a NE
can trigger the initiation of a Diameter QoS authorization session.
The NE converts the required objects from the QoS signaling message
to Diameter AVPs and generates a QAR message.</t>
<t><xref target="fig-initial-qos-request-pull"></xref> shows the
protocol interaction between a Resource Requesting Entity, a Network
Element and the Authorizing Entity.</t>
<t>The AE's identity, information about the application session
and/or identity and credentials of the QoS RRE, requested QoS
parameters, signaling session identifier and/or QoS enabled data
flows identifiers MAY be encapsulated into respective Diameter AVPs
and included in the Diameter message sent to the AE. The QAR is sent
to a Diameter server that can either be the home server of the QoS
requesting entity or an AppS.</t>
<texttable anchor="pull_mapping"
title="Mapping Input Data to QoS AVPs--Pull Mode">
<ttcol align="left">QoS-specific Input Data</ttcol>
<ttcol align="left">Diameter AVPs</ttcol>
<c>Authorizing entity ID (e.g., Destination-Host taken from
authorization token, Destination-Realm or derived from the NAI of
the QoS requesting entity)</c>
<c>Destination-Host Destination-Realm</c>
<c>Authorization Token Credentials of the QoS requesting
entity</c>
<c>QoS-Authorization-Data User-Name</c>
<c>QoS-Resources (including QoS parameters)</c>
</texttable>
<t></t>
<t>Authorization processing starts at the Diameter QoS server when
it receives the QAR. Based on the information in the
QoS-Authentication-Data, User-Name and QoS-Resources AVPs the server
determines the authorized QoS resources and flow state
(enabled/disabled) from locally available information (e.g., policy
information that may be previously established as part of an
application layer signaling exchange, or the user's subscription
profile). The QoS-Resources AVP is defined in <xref
target="I-D.ietf-dime-qos-attributes"></xref>. The authorization
decision is then reflected in the response returned to the Diameter
client with the QoS-Authorization-Answer message (QAA).</t>
<t><figure anchor="fig-initial-qos-request-pull"
title="Initial QoS Request Authorization for Pull Mode">
<artwork><![CDATA[
Authorizing
End-Host Network Element Entity
requesting QoS ( Diameter ( Diameter
QoS Client) QoS Server)
| | |
+---QoS-Reserve---->| |
| +- - - - - QAR - - - - - >|
| |(QoS-Resources, |
| | QoS-Auth-Data,User-ID)|
| | +--------+--------------+
| | | Authorize request |
| | | Keep session data |
| | |/Authz-time,Session-Id/|
| | +--------+--------------+
| |< - - - - QAA - - - - - -+
| |(Result-Code, |
| |QoS-Resources,Authz-time)|
| +-------+---------+
| |Install QoS state|
| | + |
| | Authz. session |
| | /Authz-time/ | QoS Responder
| | | Node
| +-------+---------+ |
| +----------QoS-Reserve---....--->|
| | |
| |<---------QoS-Response--....----|
|<--QoS-Response----+ |
| | |
|=====================Data Flow==============....===>|
]]></artwork>
</figure></t>
<t>The Authorizing Entity keeps authorization session state and
SHOULD save additional information for management of the session
(e.g., Signaling-Session-Id, authentication data) as part of the
session state information.</t>
<t>The final result of the authorization request is provided in the
Result-Code AVP of the QAA message sent by the Authorizing Entity.
In case of successful authorization (i.e., Result-Code =
DIAMETER_LIMITED_SUCCESS, (see <xref
target="diameter-base-avps"></xref>)), information about the
authorized QoS resources and the status of the authorized flow
(enabled/disabled) is provided in the QoS-Resources AVP of the QAA
message. The QoS information provided via the QAA is installed by
the QoS Traffic Control function of the NE. The value
DIAMETER_LIMITED_SUCCESS indicates that the AE expects confirmation
via another QAR message for successful QoS resource reservation and
for final reserved QoS resources (see below).</t>
<t>One important piece of information returned from the Authorizing
Entity is the authorization lifetime (carried inside the QAA). The
authorization lifetime allows the NE to determine how long the
authorization decision is valid for this particular QoS reservation.
A number of factors may influence the authorized session duration,
such as the user's subscription plan or currently available credits
at the user's account (see <xref target="accounting"></xref>). The
authorization duration is time-based, as specified in <xref
target="RFC3588"></xref>. For an extension of the authorization
period, a new QoS-Authorization-Request/Answer message exchange
SHOULD be initiated. Further aspects of QoS authorization session
maintenance is discussed in <xref target="re-authz"></xref>, <xref
target="session-termination"></xref> and <xref
target="accounting"></xref>.</t>
<t>The indication of a successful QoS reservation and activation of
the data flow is provided by the transmission of a QAR message,
which reports the parameters of the established QoS state: reserved
resources, duration of the reservation, and identification of the
QoS enabled flow/QoS signaling session. The Diameter QoS server
acknowledges the reserved QoS resources with the QA Answer (QAA)
message where the Result-Code is set to 'DIAMETER_SUCCESS'. Note
that the reserved QoS resources reported in this QAR message MAY be
different than those authorized with the initial QAA message, due to
the QoS signaling specific behavior (e.g., receiver-initiated
reservations with One-Path-With-Advertisements) or specific process
of QoS negotiation along the data path.</t>
</section>
<section anchor="push_setup"
title="Session Establishment for Push Mode">
<t>The Diameter QoS server in the AE initiates a Diameter QoS
authorization session upon the request for QoS reservation triggered
by application layer signaling or by local events, and generates a
QoS-Install-Request (QIR) message to Diameter QoS client in the NE
in which it maps required objects to Diameter payload objects.</t>
<t><xref target="fig-initial-qos-request-push"></xref> shows the
protocol interaction between the AE, a Network Element and a
RRE.</t>
<t>The NE's identity, information about the application session
and/or identity and credentials of the QoS resource requesting
entity, requested QoS parameters, signaling session identifier
and/or QoS enabled data flows identifiers MAY be encapsulated into
respective Diameter AVPs and included into the Diameter message sent
from a Diameter QoS server in the Authorizing Entity to a Diameter
QoS client in the NE. This requires that the AE has knowledge of
specific information for allocating and identifying the NE that
should be contacted and the data flow for which the QoS reservation
should be established. This information can be statically configured
or dynamically discovered, see <xref target="peer_discovery"></xref>
for details.</t>
<texttable anchor="push_mapping"
title="Mapping Input Data to QoS AVPs--Push Mode">
<ttcol align="left">QoS-specific Input Data</ttcol>
<ttcol align="left">Diameter AVPs</ttcol>
<c>Network Element ID</c>
<c>Destination-Host Destination-Realm</c>
<c>Authorization Token Credentials of the QoS requesting
entity</c>
<c>QoS-Authorization-Data User-Name</c>
<c>QoS-Resources (including QoS parameters)</c>
</texttable>
<t></t>
<t>Authorization processing starts at the Diameter QoS server when
it receives a request from a RRE through an AppS (e.g., SIP Invite)
or is triggered by a local event (e.g., pre-configured timer). Based
on the received information the server determines the authorized QoS
resources and flow state (enabled/disabled) from locally available
information (e.g., policy information that may be previously
established as part of an application layer signaling exchange, or
the user's subscription profile). The authorization decision is then
reflected in the QoS-Install-Request message (QIR) to the Diameter
QoS client.</t>
<t><figure anchor="fig-initial-qos-request-push"
title="Initial QoS Request Authorization for Push Mode">
<artwork><![CDATA[
Authorizing
End-Host Network Element Entity
requesting QoS ( Diameter ( Diameter
QoS Client) QoS Server)
| | |
| | |<-- Trigger --
| | +--------+--------------+
| | | Authorize request |
| | | Keep session data |
| | |/Authz-time,Session-Id/|
| | +--------+--------------+
| | |
| |<-- - -- - QIR - - - - - -+
| |(Initial Request,Decision |
| |(QoS-Resources,Authz-time)|
| +-------+---------+
| |Install QoS state|
| | + |
| | Authz. session |
| | /Authz-time/ |
| | |
| +-------+---------+
| + - - - - QIA - - - - - ->|
| | (Result-Code, |
| | QoS-Resources) |
| | +--------+--------------+
| | | Report for successful |
| | | QoS reservation |
| | |Update of reserved QoS |
| | | resources |
| | +--------+--------------+
| | QoS Responder
| | Node
| | |
|=====================Data Flow==============....===>|
]]></artwork>
</figure></t>
<t>The AE keeps authorization session state and SHOULD save
additional information for management of the session (e.g.,
Signaling-Session-Id, authentication data) as part of the session
state information.</t>
<t>The final result of the authorization decision is provided in the
QoS-Resources AVP of the QIR message sent by the AE. The QoS
information provided via the QIR is installed by the QoS Traffic
Control function of the NE.</t>
<t>One important piece of information from the AE is the
authorization lifetime (carried inside the QIR). The authorization
lifetime allows the NE to determine how long the authorization
decision is valid for this particular QoS reservation. A number of
factors may influence the authorized session duration, such as the
user's subscription plan or currently available credits at the
user's account (see <xref target="accounting"></xref>). The
authorization duration is time-based as specified in <xref
target="RFC3588"></xref>. For an extension of the authorization
period, a new QoS-Install-Request/Answer message or
QoS-Authorization-Request/Answer message exchange SHOULD be
initiated. Further aspects of QoS authorization session maintenance
are discussed in <xref target="re-authz"></xref>, <xref
target="session-termination"></xref> and <xref
target="accounting"></xref>.</t>
<t>The indication of QoS reservation and activation of the data flow
can be provided by the QoS-Install-Answer message immediately. In
the case of successful enforcement, the Result-Code (=
DIAMETER_SUCCESS, (see <xref target="diameter-base-avps"></xref>))
information is provided in the QIA message. Note that the reserved
QoS resources reported in the QIA message may be different than
those initially authorized with the QIR message, due to the QoS
signaling specific behavior (e.g., receiver-initiated reservations
with One-Path-With-Advertisements) or specific process of QoS
negotiation along the data path. In the case Multiple AEs control
the same NE, the NE should make the selection on the authorization
decision to be enforced based on the priority of the request.</t>
</section>
<section anchor="peer_discovery"
title="Discovery and Selection of Peer Diameter QoS Application Node">
<!-- <t>Discovery of Diameter QoS application nodes</t>
-->
<t>The Diameter QoS application node may obtain information of its
peer nodes (e.g., FQDN, IP address) through static configuration or
dynamic discovery as described in Section 5.2 of <xref
target="RFC3588"></xref>. In particular, the NE shall perform the
relevant operation for Pull mode; the AE shall perform the relevant
operations for Push mode.</t>
<!--
<t>Selection of peer Diameter QoS application node</t>
-->
<t>Upon receipt of a trigger to initiate a new Diameter QoS
authorization session, the Diameter QoS application node selects and
retrieves the location information of the peer node that is
associated with the affected user based on some index information
provided by the RRE. For instance, it can be the Authorization
Entity's ID stored in the authorization token, the end-user's
identity (e.g., NAI <xref target="RFC4282"></xref>) or a globally
routable IP address.</t>
</section>
</section>
<section anchor="re-authz" title="Session Re-authorization">
<t>Client and server-side initiated re-authorizations are considered
in the design of the Diameter QoS application. Whether the
re-authorization events are transparent for the resource requesting
entity or result in specific actions in the QoS signaling protocol is
outside the scope of the Diameter QoS application. It is directly
dependent on the capabilities of the QoS signaling protocol.</t>
<t>There are a number of options for policy rules according to which
the NE (AAA client) contacts the AE for re-authorization. These rules
depend on the semantics and contents of the QAA message sent by the
AE:</t>
<t><list style="letters">
<t>The QAA message contains the authorized parameters of the flow
and its QoS and sets their limits (presumably upper). With these
parameters the AE specifies the services that the NE can provide
and will be financially compensated for. Therefore, any change or
request for change of the parameters of the flow and its QoS that
do not conform to the authorized limits requires contacting the AE
for authorization.</t>
<t>The QAA message contains authorized parameters of the flow and
its QoS. The rules that determine whether parameters’
changes require re-authorization are agreed out of band, based on
a Service Level Agreement (SLA) between the domains of the NE and
the AE.</t>
<t>The QAA message contains the authorized parameters of the flow
and its QoS. Any change or request for change of these parameters
requires contacting the AE for re-authorization.</t>
<t>In addition to the authorized parameters of the flow and its
QoS, the QAA message contains policy rules that determine the NEs
actions in case of change or request for change in authorized
parameters.</t>
</list></t>
<t>Provided options are not exhaustive. Elaborating on any of the
listed approaches is deployment /solution specific and is not
considered in the current document.</t>
<t>In addition, the AE may use a RAR (Re-Authorization-Request) to
perform re-authorization with the authorized parameters directly when
the re-authorization is triggered by service request or local
events/policy rules.</t>
<section title="Client-Side Initiated Re-Authorization">
<t>The AE provides the duration of the authorization session as part
of the QoS-Authorization-Answer message (QAA). At any time before
expiration of this period, a new QoS-Authorization-Request message
(QAR) MAY be sent to the AE. The transmission of the QAR MAY be
triggered when the NE receives a QoS signaling message that requires
modification of the authorized parameters of an ongoing QoS session,
or authorization lifetime expires.</t>
<t><figure anchor="fig-qos-request-re-authz"
title="Client-side Initiated QoS Re-Authorization">
<artwork><![CDATA[
Authorizing
End-Host Network Element Entity
requesting QoS ( Diameter ( Diameter
QoS Client) QoS Server)
| | |
|=====================Data Flow==========================>
| | |
| +-------+----------+ |
| |Authz-time/CC-Time| |
| | expires | |
| +-------+----------+ |
| +- - - - - QAR - - - - - >|
| |(QoS-Resources, |
| | QoS-Authorization-Data,User-ID) |
| +--------+--------------+
NOTE: | | Authorize request |
Re-authorization | | Update session data |
is transparent to | |/Authz-time,Session-Id/|
the End-Host | +--------+--------------+
|< - - - - QAA - - - - - -+
| |(Result-Code, |
| |QoS-Resources,Authz-time)|
| +-------+---------+ |
| |Update QoS state | |
| | + | |
| | Authz. session | |
| | /Authz-time/ | |
| | | |
| +-------+---------+ |
| | |
|=====================Data Flow==========================>
| |
]]></artwork>
</figure></t>
</section>
<section title="Server-Side Initiated Re-Authorization">
<t>The AE MAY initiate a QoS re-authorization by issuing a
Re-Auth-Request message (RAR) as defined in the Diameter base
protocol <xref target="RFC3588"></xref>, which may include the
parameters of the re-authorized QoS state: reserved resources,
duration of the reservation, identification of the QoS enabled
flow/QoS signaling session for re-installation of the resource state
by the QoS Traffic Control function of the NE.</t>
<t>A NE that receives such a RAR message with Session-Id matching a
currently active QoS session acknowledges the request by sending the
Re-Auth-Answer (RAA) message towards the AE.</t>
<t>If RAR does not include any parameters of the re-authorized QoS
state, the NE MUST initiate a QoS re-authorization by sending a
QoS-Authorization-Request (QAR) message towards the AE.</t>
<t><figure anchor="fig-qos-re-auth-server-side"
title="Server-side Initiated QoS Re-Authorization">
<artwork><![CDATA[
Authorizing
End-Host Network Element Entity
requesting QoS ( Diameter ( Diameter
QoS Client) QoS Server)
| | |
| | |<-- Trigger --
| | +--------+--------------+
| | | Authorize request |
| | | Keep session data |
| | |/Authz-time,Session-Id/|
| | +--------+--------------+
| | |
| |<-- - -- - RAR - - - - - -+
| |(Request,Decision |
| |(QoS-Resources,Authz-time)|
| +-------+---------+
| |Install QoS state|
| | + |
| | Authz. session |
| | /Authz-time/ |
| | |
| +-------+---------+
| + - - - - RAA - - - - - ->|
| | (Result-Code, |
| | QoS-Resources) |
| | +--------+--------------+
| | | Report for successful |
| | | QoS reservation |
| | |Update of reserved QoS |
| | | resources |
| | +--------+--------------+
| | |
]]></artwork>
</figure></t>
</section>
</section>
<section anchor="session-termination" title="Session Termination">
<section title="Client-Side Initiated Session Termination">
<t>The authorization session for an installed QoS reservation state
MAY be terminated by the Diameter client by sending a
Session-Termination-Request message (STR) to the Diameter server
with a response Session-Termination-Acknowledgement message (STA).
This is a Diameter base protocol function and it is defined in <xref
target="RFC3588"></xref>. Session termination can be caused by a QoS
signaling messaging requesting deletion of the existing QoS
reservation state or it can be caused as a result of a soft-state
expiration of the QoS reservation state.</t>
<t><figure anchor="fig-client-termination"
title="Client-Side Initiated Session Termination">
<artwork><![CDATA[
Authorizing
End-Host Network Element Entity
requesting QoS ( Diameter ( Diameter
QoS Client) QoS Server)
| | |
|==Data Flow==>X /Stop of the data flow/ |
| | |
+---QoS-Reserve---->| |
| (Delete QoS +- - - - - STR - - - - - >|
| reservation) | +--------+--------------+
| | | Remove authorization |
| | | session state |
| | +--------+--------------+
| |< - - - - STA - - - - - -+
| +-------+--------+ |
| |Delete QoS state|
| +-------+--------+ QoS Responder
| | Node
| +----------QoS-Reserve-----....--->|
| | (Delete QoS |
| | reservation) |
| |<---------QoS-Response----....----+
|<--QoS-Response----+ |
]]></artwork>
</figure></t>
</section>
<section title="Server-Side Initiated Session Termination">
<t>At anytime during a session the AE MAY send an
Abort-Session-Request message (ASR) to the NE. This is a Diameter
base protocol function and it is defined in <xref
target="RFC3588"></xref>. Possible reasons for initiating the ASR
message to the NE are insufficient credits or session termination at
the application layer. The ASR message results in termination of the
authorized session, release of the reserved resources at the NE and
transmission of an appropriate QoS signaling message indicating a
notification to other Network Elements aware of the signaling
session.</t>
<t><figure anchor="fig-server-termination"
title="Server-Side Initiated Session Termination">
<artwork><![CDATA[
Authorizing
End-Host Network Element Entity
requesting QoS ( Diameter ( Diameter
QoS Client) QoS Server)
| | |
|=====================Data Flow==========================>
| |
| |< - - - - ASR - - - - - -+
| | |
|====Data Flow=====>X | QoS Responder
| | | Node
|<--QoS-Notify------+----------QoS-Reserve-----....--->|
| | (Delete QoS | |
| reservation) |
+-------+--------+ |
|Delete QoS state| |
+-------+--------+ |
+- - - - - ASA - - - - - >|
| +--------+--------------+
| | Remove authorization |
| | session state |
| +--------+--------------+
| QoS Responder
| Node
|<---------QoS-Response----....----+
| |
]]></artwork>
</figure></t>
</section>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="qos_messages" title="QoS Application Messages">
<t>The Diameter QoS application requires the definition of new mandatory
AVPs and Command-codes (see Section 3 of <xref
target="RFC3588"></xref>). Four new Diameter messages are defined along
with Command-Codes whose values MUST be supported by all Diameter
implementations that conform to this specification.</t>
<texttable anchor="qos_commands" title="Diameter QoS Commands">
<ttcol align="left">Command Name</ttcol>
<ttcol align="center">Abbrev.</ttcol>
<ttcol align="center">Code</ttcol>
<ttcol align="left">Reference</ttcol>
<c>QoS-Authorization-Request</c>
<c>QAR</c>
<c>[TBD1]</c>
<c><xref target="QAR"></xref></c>
<c>QoS-Authorization-Answer</c>
<c>QAA</c>
<c>[TBD2]</c>
<c><xref target="QAA"></xref></c>
<c>QoS-Install-Request</c>
<c>QIR</c>
<c>[TBD3]</c>
<c><xref target="QIR"></xref></c>
<c>QoS-Install-Answer</c>
<c>QIA</c>
<c>[TBD4]</c>
<c><xref target="QIA"></xref></c>
</texttable>
<!--
<t><figure>
<artwork><![CDATA[
Command-Name Abbrev. Code Reference
QoS-Authorization-Request QAR [TBD1] Section 5.1
QoS-Authorization-Answer QAA [TBD2] Section 5.2
QoS-Install-Request QIR [TBD3] Section 5.3
QoS-Install-Answer QIA [TBD4] Section 5.4
]]></artwork>
</figure></t>
-->
<t>In addition, the following Diameter Base protocol messages are used
in the Diameter QoS application:</t>
<!--
<t><figure>
<artwork><![CDATA[
Command-Name Abbrev. Code Reference
Re-Auth-Request RAR 258 RFC 3588
Re-Auth-Answer RAA 258 RFC 3588
Abort-Session-Request ASR 274 RFC 3588
Abort-Session-Answer ASA 274 RFC 3588
Session-Term-Request STR 275 RFC 3588
Session-Term-Answer STA 275 RFC 3588
]]></artwork>
</figure></t>
-->
<texttable anchor="base_messages" title="Diameter Base Commands">
<ttcol align="left">Command-Name</ttcol>
<ttcol align="center">Abbrev.</ttcol>
<ttcol align="center">Code</ttcol>
<ttcol align="left">Reference</ttcol>
<c>Re-Auth-Request</c>
<c>RAR</c>
<c>258</c>
<c><xref target="RFC3588"></xref></c>
<c>Re-Auth-Answer</c>
<c>RAA</c>
<c>258</c>
<c><xref target="RFC3588"></xref></c>
<c>Abort-Session-Request</c>
<c>ASR</c>
<c>274</c>
<c><xref target="RFC3588"></xref></c>
<c>Abort-Session-Answer</c>
<c>ASA</c>
<c>274</c>
<c><xref target="RFC3588"></xref></c>
<c>Session-Term-Request</c>
<c>STR</c>
<c>275</c>
<c><xref target="RFC3588"></xref></c>
<c>Session-Term-Answer</c>
<c>STA</c>
<c>275</c>
<c><xref target="RFC3588"></xref></c>
</texttable>
<t>Diameter nodes conforming to this specification MAY advertise support
for the Diameter QoS application by including the value of [TBD5] in the
Auth-Application-Id or the Acct-Application-Id AVP of the
Capabilities-Exchange-Request and Capabilities-Exchange-Answer commands,
see <xref target="RFC3588"></xref>.</t>
<t>The value of {TBD5] MUST be used as the Application-Id in all QAR/QAA
and QIR/QIA commands.</t>
<t>The value of zero (0) SHOULD be used as the Application-Id in all
STR/STA, ASR/ASA, and RAR/RAA commands.</t>
<section anchor="QAR" title="QoS-Authorization Request (QAR)">
<t>The QoS-Authorization-Request message (QAR) indicated by the
Command-Code field (see Section 3 of <xref target="RFC3588"></xref>)
set to [TBD1] and 'R' bit set in the Command Flags field is used by
NEs to request quality of service related resource authorization for a
given flow.</t>
<t>The QAR message MUST carry information for signaling session
identification, AE identification, information about the requested
QoS, and the identity of the QoS requesting entity. In addition,
depending on the deployment scenario, an authorization token and
credentials of the QoS requesting entity SHOULD be included.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<QoS-Request> ::= < Diameter Header: [TBD1], REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ Destination-Host ]
[ User-Name ]
* [ QoS-Resources ]
[ QoS-Authorization-Data ]
[ Bound-Auth-Session-Id ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section anchor="QAA" title="QoS-Authorization Answer (QAA)">
<t>The QoS-Authorization-Answer message (QAA), indicated by the
Command- Code field set to [TBD2] and 'R' bit cleared in the Command
Flags field is sent in response to the QoS-Authorization-Request
message (QAR). If the QoS authorization request is successfully
authorized, the response will include the AVPs to allow authorization
of the QoS resources and transport plane gating information.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<QoS-Answer> ::= < Diameter Header: [TBD2], PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Request-Type }
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
* [ QoS-Resources ]
[ Acct-Multisession-Id ]
[ Session-Timeout ]
[ Authorization-Session-Lifetime ]
[ Authorization-Grace-Period ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section anchor="QIR" title="QoS-Install Request (QIR)">
<t>The QoS-Install Request message (QIR), indicated by the
Command-Code field set to [TBD3] and 'R' bit set in the Command Flags
field is used by AE to install or update the QoS parameters and the
flow state of an authorized flow at the transport plane element.</t>
<t>The message MUST carry information for signaling session
identification or identification of the flow to which the provided QoS
rules apply, identity of the transport plane element, description of
provided QoS parameters, flow state and duration of the provided
authorization.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<QoS-Install-Request> ::= < Diameter Header: [TBD3], REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ Destination-Host ]
* [ QoS-Resources ]
[ Session-Timeout ]
[ Authorization-Session-Lifetime ]
[ Authorization-Grace-Period ]
[ Authorization-Session-Volume ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section anchor="QIA" title="QoS-Install Answer (QIA)">
<t>The QoS-Install Answer message (QIA), indicated by the Command-Code
field set to [TBD4] and 'R' bit cleared in the Command Flags field is
sent in response to the QoS-Install Request message (QIR) for
confirmation of the result of the installation of the provided QoS
reservation instructions.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<QoS-Install-Answer> ::= < Diameter Header: [TBD4], PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Result-Code }
* [ QoS-Resources ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section anchor="RAR" title="Re-Auth-Request (RAR)">
<t>The Re-Auth-Request message (RAR), indicated by the Command-Code
field set to 258 and the 'R' bit set in the Command Flags field, is
sent by the AE to the NE in order to initiate the QoS re-authorization
from DQA server side.</t>
<t>If the RAR command is received by the NE without any parameters of
the re-authorized QoS state, the NE MUST initiate a QoS
re-authorization by sending a QoS-Authorization-Request (QAR) message
towards the AE.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<RAR> ::= < Diameter Header: 258, REQ, PXY >
< Session-Id >
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Destination-Host }
{ Auth-Application-Id }
{ Re-Auth-Request-Type }
[ User-Name ]
[ Origin-State-Id ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ QoS-Resources ]
[ Session-Timeout ]
[ Authorization-Session-Lifetime ]
[ Authorization-Grace-Period ]
[ Authorization-Session-Volume ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section anchor="RAA" title="Re-Auth-Answer (RAA)">
<t>The Re-Auth-Answer message (RAA), indicated by the Command-Code
field set to 258 and the 'R' bit cleared in the Command Flags field,
is sent by the NE to the AE in response to the RAR command.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<RAA> ::= < Diameter Header: 258, PXY >
< Session-Id >
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ User-Name ]
[ Origin-State-Id ]
[ Error-Message ]
[ Error-Reporting-Host ]
* [ Failed-AVP ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Host-Cache-Time ]
* [ Proxy-Info ]
* [ QoS-Resources ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="QoS_state_machine" title="QoS Application State Machine">
<t>The QoS application defines its own state machine that is based on
the authorization state machine defined in Section 8.1 of the Base
Protocol (<xref target="RFC3588"></xref>). The Qos state machine uses
own messages as defined in <xref target="qos_messages"></xref> and QoS
AVPs as defined in <xref target="avps"></xref>.</t>
<section anchor="state_supplement"
title="Supplemented States for Push Mode">
<t>Using the Base Protocol state machine as a basis, the following
states are supplemented to first 2 state machines in which the session
state is maintained on the Server. These MUST be supported in any QoS
application implementations in support of server initiated push mode
(<xref target="push_setup">see</xref>).</t>
<t>The following states are supplemented to the state machine on the
Server when state is maintained on the client as defined in Section
8.1 of the Base Protocol <xref target="RFC3588"></xref>:</t>
<t><figure align="left">
<artwork><![CDATA[ SERVER, STATEFUL
State Event Action New State
-------------------------------------------------------------
Idle An application or local Send Pending
event triggers an initial QIR initial
QoS request to the server request
Pending Received QIA with a failed Cleanup Idle
Result-Code
Pending Received QIA with Result-Code Update Open
= SUCCESS session
Pending Error in processing received Send Discon
QIA with Result-Code = SUCCESS ASR
]]></artwork>
</figure></t>
<t>The following states are supplemented to the state machine on the
client when state is maintained on the server as defined in Section
8.1 of the Base Protocol <xref target="RFC3588"></xref>:</t>
<t><figure align="left">
<artwork><![CDATA[ CLIENT, STATEFUL
State Event Action New State
-------------------------------------------------------------
Idle QIR initial request Send Open
received and successfully QIA initial
processed answer,
reserve resources
Idle QIR initial request Send Idle
received but not QIA initial
successfully processed answer with
Result-Code
!= SUCCESS
]]></artwork>
</figure></t>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="avps" title="QoS Application AVPs">
<t>Each of the AVPs identified in the QoS-Authorization-Request/Answer
and QoS-Install-Request/Answer messages and the assignment of their
value(s) is given in this section.</t>
<section anchor="diameter-base-avps" title="Reused Base Protocol AVPs">
<t>The QoS application uses a number of session management AVPs,
defined in the Base Protocol (<xref target="RFC3588"></xref>).</t>
<t><figure>
<artwork><![CDATA[
Attribute Name AVP Code Reference [RFC3588]
Origin-Host 264 Section 6.3
Origin-Realm 296 Section 6.4
Destination-Host 293 Section 6.5
Destination-Realm 283 Section 6.6
Auth-Application-Id 258 Section 6.8
Result-Code 268 Section 7.1
Auth-Request-Type 274 Section 8.7
Session-Id 263 Section 8.8
Authorization-Lifetime 291 Section 8.9
Authorization-Grace-Period 276 Section 8.10
Session-Timeout 27 Section 8.13
User-Name 1 Section 8.14
]]></artwork>
</figure></t>
<t>The Auth-Application-Id AVP (AVP Code 258) is assigned by IANA to
Diameter applications. The value of the Auth-Application-Id for the
Diameter QoS application is TBD.</t>
</section>
<section anchor="qos-new-avps" title="QoS Application Defined AVPs">
<t></t>
<t>This document reuses the AVPs defined in Section 4 of <xref
target="I-D.ietf-dime-qos-attributes"></xref>.</t>
<t>This section lists the AVPs that are introduced specifically for
the QoS application. The following new AVPs are defined:
Bound-Auth-Session-Id and the QoS-Authorization-Data AVP.</t>
<t>The following table describes the Diameter AVPs newly defined in
this document for usage with the QoS Application, their AVP code
values, types, possible flag values, and whether the AVP may be
encrypted.</t>
<t><figure>
<artwork><![CDATA[
+-------------------+
| AVP Flag rules |
+----------------------------------------------|----+--------+-----+
| AVP Section | | SHLD| MUST|
| Attribute Name Code Defined Data Type |MUST| NOT| NOT|
+----------------------------------------------+----+--------+-----+
|QoS-Authorization-Data TBD 7.2 OctetString| M | | V |
|Bound-Auth-Session-Id TBD 7.2 UTF8String | M | | V |
+----------------------------------------------+----+--------+-----+
|M - Mandatory bit. An AVP with "M" bit set and its value MUST be |
| supported and recognized by a Diameter entity in order the |
| message, which carries this AVP, to be accepted. |
|V - Vendor specific bit that indicates whether the AVP belongs to |
| a address space. |
+------------------------------------------------------------------+
]]></artwork>
</figure></t>
<t></t>
<t><list style="hanging">
<t hangText="QoS-Authorization-Data"><vspace blankLines="0" /> The
QoS-Authorization-Data AVP (AVP Code TBD) is of type OctetString.
It is a container that carries application session or user
specific data that has to be supplied to the AE as input to the
computation of the authorization decision. <vspace
blankLines="1" /></t>
<t hangText="Bound-Authentication-Session-Id"><vspace
blankLines="0" /> The Bound-Authentication-Session AVP (AVP Code
TBD) is of type UTF8String. It carries the id of the Diameter
authentication session that is used for the network access
authentication (NASREQ authentication session). It is used to tie
the QoS authorization request to a prior authentication of the end
host done by a co-located application for network access
authentication (Diameter NASREQ) at the QoS NE. <vspace
blankLines="1" /></t>
</list></t>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="accounting" title="Accounting">
<t>A NE MAY start an accounting session by sending an Accounting-Request
message (ACR) after successful QoS reservation and activation of the
data flow (see <xref target="fig-initial-qos-request-pull"></xref> and
<xref target="fig-initial-qos-request-push"></xref>). After every
successful re-authorization procedure (see <xref
target="fig-qos-request-re-authz"></xref> and <xref
target="fig-qos-re-auth-server-side"></xref>), the NE MAY initiate an
interim accounting message exchange. After successful session
termination (see <xref target="fig-client-termination"></xref> and <xref
target="fig-server-termination"></xref>), the NE may initiate a final
exchange of accounting messages for terminating of the accounting
session and reporting final records for the usage of the QoS resources
reserved. It should be noted that the two sessions (authorization and
accounting) have independent management by the Diameter base protocol,
which allows for finalizing the accounting session after the end of the
authorization session.</t>
<t>The detailed QoS accounting procedures are out of scope in this
document.</t>
</section>
<!-- ====================================================================== -->
<section anchor="examples" title="Examples">
<section anchor="example_pull" title="Example Call Flow for Pull Mode">
<t>This section presents an example of the interaction between the end
host and Diameter QoS application entities using Pull mode. The
application layer signaling is, in this example, provided using SIP.
Signaling for a QoS resource reservation is done using the QoS NSLP.
The authorization of the QoS reservation request is done by the
Diameter QoS application (DQA).<figure anchor="fig-example-pull"
title="QoS Authorization Example - Pull Mode">
<artwork><![CDATA[
End-Host SIP Server Correspondent
requesting QoS (DQA Server) Node
| | |
..|....Application layer SIP signaling.......|..............|..
. | Invite (SDP) | | .
. +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-> | .
. | 100 Trying | | .
. <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ Invite (SDP)| .
. | +-.-.-.....-.-.> .
. | | 180 SDP' | .
. | <-.-.-.....-.-.+ .
. | +--------+--------+ | .
. | |Authorize session| | .
. | | parameters | | .
. | 180 (Session parameters) +--------+--------+ | .
. <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-+ | .
..|..........................................|... ..........|..
| | |
| +------------+ | |
| | NE | | |
| |(DQA Client)| | |
| +------+-----+ | |
| | | |
|QoS NSLP Reserve | | |
+------------------> QAR | |
| (POLICY_DATA>v +- - - - -<<AAA>>- - - -> |
| QSPEC) v >===>(Destination-Host, | |
| v >=======>QoS-Authorization-Data++------------+ |
| >===========>QoS-Resources) |Authorize | |
| | |QoS resources| |
| | ++------------+ |
| | QAA | |
| <- - - - -<<AAA>>- - - -+ |
| |(Result-Code, | |
| |QoS-Resources, | |
| |Authorization-Lifetime)| |
| +---------+--------+ | |
| |Install QoS state1| | |
| |+ Authz. session | | |
| +---------+--------+ | |
| |QoS NSLP Reserve |
| +---------------..............--------->
| | |
| | QoS NSLP Response|
|QoS NSLP Response <---------------..............---------+
<------------------+ |
| | QoS NSLP Query|
|QoS NSLP Query <---------------..............---------+
<------------------+ |
|QoS NSLP Reserve | |
+------------------> QAR | |
| +- - - - -<<AAA>>- - - -> |
| | +---+---------+ |
| | |Authorize | |
| | |QoS resources| |
| | QAA +---+---------+ |
| <- - - - -<<AAA>>- - - -+ |
| +---------+--------+ | |
| |Install QoS state2| |
| |+ Authz. session | |
| +---------+--------+ |
| | QoS NSLP Reserve |
| +---------------..............--------->
| | QoS NSLP Response|
|QoS NSLP Response <---------------..............---------+
<------------------+ |
| | |
/------------------+--Data Flow---------------------------\
\------------------+--------------------------------------/
| | |
.-.-.-.-. SIP signaling
--------- QoS NSLP signaling
- - - - - Diameter QoS Application messages
========= Mapping of objects between QoS and AAA protocol
]]></artwork>
</figure></t>
<t>The communication starts with SIP signaling between the two end
points and the SIP server for negotiation and authorization of the
requested service and its parameters (see <xref
target="fig-example-pull"></xref>). As a part of the process, the SIP
server verifies whether the user at Host A is authorized to use the
requested service (and potentially the ability to be charged for the
service usage). Negotiated session parameters are provided to the end
host.</t>
<t>Subsequently, Host A initiates a QoS signaling message towards Host
B. It sends a QoS NSLP Reserve message, in which it includes
description of the required QoS (QSPEC object) and authorization data
for negotiated service session (part of the POLICY_DATA object).
Authorization data includes, as a minimum, the identity of the AE
(e.g., the SIP server) and an identifier of the application service
session for which QoS resources are requested.</t>
<t>A QoS NSLP Reserve message is intercepted and processed by the
first QoS aware Network Element. The NE uses the Diameter QoS
application to request authorization for the received QoS reservation
request. The identity of the AE (in this case the SIP server that is
co-located with a Diameter server) is put into the Destination-Host
AVP, any additional session authorization data is encapsulated into
the QoS-Authorization-Data AVP and the description of the QoS
resources is included into QoS-Resources AVP. These AVPs are included
into a QoS Authorization Request message, which is sent to the AE.</t>
<t>A QAR message will be routed through the AAA network to the AE. The
AE verifies the requested QoS against the QoS resources negotiated for
the service session and replies with QoS-Authorization answer (QAA)
message. It carries the authorization result (Result-Code AVP) and the
description of the authorized QoS parameters (QoS-Resources AVP), as
well as duration of the authorization session (Authorization-Lifetime
AVP).</t>
<t>The NE interacts with the traffic control function and installs the
authorized QoS resources and forwards the QoS NSLP Reserve message
further along the data path. Moreover, the NE may serve as a signaling
proxy and process the QoS signaling (e.g., initiation or termination of
QoS signaling) based on the QoS decision received from the authorizing
entity.</t>
</section>
<section anchor="example_push" title="Example Call Flow for Push Mode">
<t>This section presents an example of the interaction between the
end-host and Diameter QoS application entities using Push mode. The
application layer signaling is, in this example, provided using SIP.
Signaling for a QoS resource reservation is done using the QoS NSLP.
The authorization of the QoS reservation request is done by the
Diameter QoS application (DQA).<figure anchor="fig-example-push"
title="QoS Authorization Example - Push Mode">
<artwork><![CDATA[
End-Host NE SIP Server Correspondent
requesting QoS (DQA Client) (DQA Server) Node
| | | |
..|....Application layer SIP signaling..........|..............|..
. | Invite(SDP offer)| | | .
. +.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.> | .
. | 100 Trying | | | .
. <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+ | .
. |.............................................|..............| .
| | +---------+-------------+|
| | | Authorize request ||
| | | Keep session data ||
| | |/Authz-time,Session-Id/||
| | +---------+-------------+|
| | | |
| |<-- - -- - QIR - -- - -- -+ |
| |(Initial Request,Decision | |
| |(QoS-Resources,Authz-time)| |
| +-------+---------+ | |
| |Install QoS state| | |
| | + | | |
| | Authz. session | | |
| | /Authz-time/ | | |
| +-------+---------+ | |
| + - - -- - QIA - - - - - ->| |
| | (Result-Code, | |
| | QoS-Resources) | |
| | +----------+------------+ |
| | | Report for successful | |
| | | QoS reservation | |
| | |Update of reserved QoS | |
| | | resources | |
| | +----------+------------+ |
. | | | Invite (SDP) | .
. | | +-.-.-.....-.-.> .
. | 180 (Ringing) | | .
. <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.<.-.-.-.-.-.-.-+ .
. | | | 200 OK (SDP)| .
. | | <-.-.-.....-.-.+ .
| | +--------+-----------+ |
| | |re-Authorize session| |
| | | parameters | |
| | +--------+-----------+ |
| <- - - - - - RAR - - - - - + |
| +---------+--------+ | |
| |Activate QoS state| | |
| +---------+--------+ | |
| +- - - - - - RAA - - - - - > |
. | 200 (SDP answer) | | | .
. <.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.+ | .
| | |
/------------------+-----Data Flow---------------------------\
\------------------+-----------------------------------------/
| | |
.-.-.-.-. SIP signaling
- - - - - Diameter QoS Application messages
]]></artwork>
</figure></t>
<t>The communication starts with SIP signaling between the two end
points and the SIP server for negotiation and authorization of the
requested service and its parameters (see <xref
target="fig-example-push"></xref>). As a part of the process, the SIP
server verifies whether the user at Host A is authorized to use the
requested service (and potentially the ability to be charged for the
service usage). The DQA server is triggered to authorize the QoS
request based on session parameters (i.e., SDP offer), initiate a
Diameter QoS authorization session and install authorized QoS state to
the Network Element via QIR message.</t>
<t>The DQA server may obtain the info of peer DQA client from
pre-configured information or query the DNS based on Host A's identity
or IP address (In this case a DQA server is co-located with a SIP
server and a DQA client is co-located with a NE). The identity of
Network Element is put into the Destination-Host AVP, the description
of the QoS resources is included into QoS-Resources AVP, as well as
duration of the authorization session (Authorization-Lifetime AVP).
The NE interacts with the traffic control function and reserves the
authorized QoS resources accordingly, for instance, the NE may serve
as a signaling proxy and process the QoS signaling (e.g., initiation or
termination of QoS signaling) based on the QoS decision received from
the authorizing entity.</t>
<t>With successful QoS authorization, the SDP offer in SIP Invite is
forwarded to Host B. Host B sends back a 18x (ringing) message towards
Host A and processes the SDP. Once Host B accepts the call, it sends
back a 200 OK, in which it includes description of the accepted
session parameters (i.e., SDP answer).</t>
<t>The DQA server may verify the accepted QoS against the
pre-authorized QoS resources, and sends a Diameter RAR message to the
DQA client in the NE for activating the installed policies and commit
the resource allocation. With successful QoS enforcement, the 200 OK
is forwarded towards Host A.</t>
<t>Note that the examples above show a sender-initiated reservation
from the end host towards the corresponding node and a
receiver-initiated reservation from the correspondent node towards the
end host.</t>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="iana" title="IANA Considerations">
<t>This section contains the namespaces that have either been created in
this specification or had their values assigned to existing namespaces
managed by IANA.</t>
<section title="AVP Codes">
<t>IANA is requested to allocate two AVP codes to the registry defined in <xref target="RFC3588"/>:</t>
<t><figure>
<artwork><![CDATA[
Registry:
AVP Code AVP Name Reference
-----------------------------------------------------------
to be assigned QoS-Authorization-Data Section 7.2
to be assigned Bound-Auth-Session-Id Section 7.2
]]></artwork>
</figure></t>
</section>
<!--
<section title="AVP Specific Values">
<t>IANA is requested to allocate the following sub-registry
values.</t>
<t><figure>
<artwork><![CDATA[
Sub-registry: Auth-Application-Id AVP Values (code 258)
Registry:
AVP Values Attribute Name Reference
------------- -------------------------------------------
to be assigned DIAMETER-QOS-NOSUPPORT Section 5
to be assigned DIAMETER-QOS-SUPPORT Section 5
]]></artwork>
</figure></t>
<t><figure>
<artwork><![CDATA[
Sub-registry: Acct-Application-Id AVP Values (code 259)
Registry:
AVP Values Attribute Name Reference
------------- -------------------------------------------
to be assigned DIAMETER-QOS-NOSUPPORT Section 5
to be assigned DIAMETER-QOS-SUPPORT Section 5
]]></artwork>
</figure></t>
</section>
-->
<!--
<section title="AVP Flags">
<t>There are no new AVP flags defined for either the
QoS-Authorization-Data AVP or the Bound-Ath-Session-ID AVP.</t>
</section>
-->
<section title="Application IDs">
<t>IANA is requested to allocate the following application ID from the registry defined
in <xref target="RFC3588"/> (using
the next available value from the 7-16777215 range). <figure>
<artwork><![CDATA[
Registry:
ID values Name Reference
-----------------------------------------------------------
to be assigned Diameter QoS application Section 5
]]></artwork>
</figure></t>
</section>
<section title="Command Codes">
<t>IANA is requested to allocate command code values from the registry defined
in <xref target="RFC3588"/>.</t>
<t><figure>
<artwork><![CDATA[
Registry:
Code Value Name Reference
-----------------------------------------------------------
TBD QoS-Authorization-Request (QAR) Section 5.1
TBD QoS-Authorization-Answer (QAA) Section 5.2
TBD QoS-Install-Request (QIR) Section 5.3
TBD QoS-Install-Answer (QIA) Section 5.4
]]></artwork>
</figure></t>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="security" title="Security Considerations">
<t>This document describes a mechanism for performing authorization of a
QoS reservation at a third party entity. The Authorizing Entity needs sufficient information to make
such an authorization decision. Information may come from various
sources, including the application layer signaling, the Diameter
protocol (with its security mechanisms), from policy information stored
available with a AAA server and from a QoS signaling protocol.</t>
<t>Below there is a discussion about considerations for the Diameter QoS
interaction between an Authorizing Entity and a Network Element.
Security between the Authorizing Entity and the Network Element has a
number of components: authentication, authorization, integrity and
confidentiality.</t>
<t>Authentication refers to confirming the identity of an originator for
all datagrams received from the originator. Lack of authentication of
Diameter messages between the Authorizing Entity and the Network Element
can seriously jeopardize the fundamental service rendered by the Network
Element. A consequence of not authenticating the message sender by the
Network Element would be that an attacker could spoof the identity of a
"legitimate" Authorizing Entity in order to allocate resources, change
resource assignments or free resources. The adversary can also
manipulate the state at the Network Element in such a way that it leads
to a denial of service attack by, for example, setting the allowed
bandwidth to zero or allocating the entire bandwidth available to a
single flow.</t>
<t>A consequence of not authenticating the Network Element to an
Authorizing Entity is that an attacker could impact the policy based
admission control procedure operated by the Authorizing Entity that
provides a wrong view of the resources used in the network. Failing to
provide the required credentials should be subject to logging.</t>
<t>Authorization refers to whether a particular Authorizing Entity is
authorized to signal a Network Element with requests for one or more
applications, adhering to a certain policy profile. Failing the
authorization process might indicate a resource theft attempt or failure
due to administrative and/or credential deficiencies. In either case,
the Network Element should take the proper measures to log such
attempts.</t>
<t>Integrity is required to ensure that a Diameter message has not been
maliciously altered. The result of a lack of data integrity enforcement
in an untrusted environment could be that an imposter will alter the
messages exchanged between a Network Entity and an Authorizing Entity
potentially causing a denial of service.</t>
<t>Confidentiality protection of Diameter messages ensures that the
signaling data is accessible only to the authorized entities. When
signaling messages from the Application Server, via the Authorizing
Entity towards the Network Element traverse untrusted networks, lack of
confidentiality will allow eavesdropping and traffic analysis.
Additionally, Diamater QoS messages may carry authorization tokens that
require confidentiality protection.</t>
<t>Diameter offers security mechanisms to deal with the functionality
demanded in the paragraphs above. In particular, Diameter offers
communication security between neighboring Diameter peers using
Transport Layer Security (TLS) or IPsec. Authorization capabilities are
application specific and part of the overal implementation.</t>
</section>
<!-- ====================================================================== -->
<section title="Acknowledgements">
<t>The authors would like to thank John Loughney and Allison Mankin for
their input to this document. In September 2005 Robert Hancock, Jukka
Manner, Cornelia Kappler, Xiaoming Fu, Georgios Karagiannis and Elwyn
Davies provided a detailed review. Robert also provided us with good
feedback earlier in 2005. Jerry Ash provided us review comments late
2005/early 2006. Rajith R provided some inputs to the document early
2007.</t>
<t>We would also like to thanks Alexey Melnikov, Adrian Farrel, and
Robert Sparks for their IESG reviews.</t>
</section>
<!-- ====================================================================== -->
<section anchor="contributors" title="Contributors">
<t>The authors would like to thank Tseno Tsenov and Frank Alfano for
starting the Diameter Quality of Service work within the IETF, for your
significant draft contributions and for being the driving force for the
first few draft versions.</t>
</section>
</middle>
<!-- ====================================================================== -->
<back>
<references title="Normative References">
&RFC2119;
&RFC3588;
&RFC4005;
&I-D.ietf-dime-qos-attributes;
&RFC5624;
</references>
<references title="Informative References">
&I-D.ietf-nsis-qos-nslp;
&RFC4566;
&RFC2211;
&RFC2212;
&RFC2205;
&RFC2753;
&RFC2865;
&RFC3521;
&RFC3313;
&I-D.ietf-nsis-ntlp;
&RFC3520;
&RFC2474;
&RFC5246;
&RFC4282;
&RFC3261;
</references>
<!-- ====================================================================== -->
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 09:32:24 |