One document matched: draft-ietf-dime-diameter-qos-04.xml
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<rfc category="std" docName="draft-ietf-dime-diameter-qos-04.txt"
ipr="full3978">
<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>600-700 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>dongsun@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 initials="H." surname="Tschofenig" fullname="Hannes 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@nsn.com</email>
<uri>http://www.tschofenig.com</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.W." surname="Zorn">
<organization>Aruba Networks</organization>
<address>
<postal>
<street>1322 Crossman Avenue</street>
<city>Sunnyvale</city>
<region>CA</region>
<code>94089-1113</code>
<country>USA</country>
</postal>
<email>gwz@arubanetworks.com</email>
</address>
</author>
<date year="2008" />
<area>Operations and Management Area</area>
<keyword>AAA, QoS, VoIP, SIP</keyword>
<abstract>
<t>This document describes 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 - Pull and Push are defined.</t>
</abstract>
</front>
<middle>
<!-- ====================================================================== -->
<section anchor="introduction" title="Introduction">
<t>This document describes framework, messages and procedures for the
Diameter 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>In particular, two modes of operation are defined. In the first,
called "Pull Mode", the network element pro-actively sends a command to
the Diameter server for QoS authorization 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
SIP-based (Session Initiation Protocol) call control.</t>
<t>A set of command codes pertinent to this QoS application are
specified that allows a single Diameter application to support both Pull
and Push modes based on the requirements of network technologies,
deployment scenarios and end-host's capabilities. In conjunction with
parameters defined in <xref
target="I-D.ietf-dime-qos-attributes"></xref> and in <xref
target="I-D.ietf-dime-qos-parameters"></xref>, this document depicts
basic call flow procedures to establish, modify and terminate a Diameter
QoS application session.</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="Diameter QoS Application Server"><vspace
blankLines="1" /> A Diameter QoS application server is a logical
Diameter node that supports the protocol interaction for QoS
authorization. The Diameter QoS application server resides in the
authorizing entity (AE). In the Pull mode, it responds to a Diameter
session initiated by a Diameter QoS application client; in the Push
mode, it initiates a Diameter session to a Diameter QoS application
client triggered by application signaling or local events.<vspace
blankLines="1" /></t>
<t hangText="Diameter QoS Application Client"><vspace
blankLines="1" /> A Diameter QoS application client is a logical
Diameter node that supports the protocol interaction for QoS
enforcement. The Diameter QoS client resides in the network element.
In the Pull mode, it initiates a Diameter session to the Diameter
QoS application server triggered by a QoS signaling or other events;
in the Push mode, it responds to a Diameter session initiated by a
Diameter QoS server.<vspace blankLines="1" /></t>
<t hangText="Resource Requesting Entity"><vspace blankLines="1" /> A
resource requesting entity is a logical entity that supports the
protocol interaction for QoS resources. The resource requesting
entity resides in the end-host and is able to communicate with peer
logical entities in Authorizing Entity or Network element to trigger
the QoS authorization process.<vspace blankLines="1" /></t>
<t hangText="Application Server"><vspace blankLines="1" /> An
application server is a network entity that exchanges signaling
messages with an application endpoint. 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="Application Endpoint"><vspace blankLines="1" /> 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="Authorizing Entity"><vspace blankLines="1" /> The
authorizing entity acts as a Diameter server (and may collocate with
a subscriber database) responsible for authorizing QoS requests for
a particular application flow or aggregate. It may be a standalone
entity or integrated with an application server. This entity
corresponds to the Policy Decision Point (PDP) (see <xref
target="RFC2753"></xref>).<vspace blankLines="1" /></t>
<t hangText="AAA Cloud"><vspace blankLines="1" /> An infrastructure
of AAA entities (clients, agents, servers) based on a AAA protocol,
which provides trusted secure connections between them. It offers
authentication, authorization and accounting services to
applications in flexible local and roaming scenarios. Diameter <xref
target="RFC3588"></xref> and RADIUS <xref target="RFC2865"></xref>
are both widely deployed AAA protocols. <vspace
blankLines="1" /></t>
<t hangText="Network Element (NE)"><vspace blankLines="1" /> QoS
aware router that acts as Diameter client that implements the
Diameter QoS application in the context of this document. For almost
all scenarios this entity triggers the protocol interaction
described in this document. This entity corresponds to the Policy
Enforcement Point (PEP) (see <xref target="RFC2753"></xref>).<vspace
blankLines="1" /></t>
<t hangText="Pull Mode"><vspace blankLines="1" />In this mode, the
QoS authorization process is invoked by the QoS reservation request
received from the endpoint. The Network Element then requests the
QoS authorization decision from the Authorizing entity.<vspace
blankLines="1" /></t>
<t hangText="Push Mode"><vspace blankLines="1" />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>
</list></t>
</section>
<!-- ====================================================================== -->
<section anchor="architecture" title="Framework">
<t>The Diameter QoS application runs between a network element (acting
as a Diameter client) and the resource authorizing entity (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 network elements through
which media flows need to pass, a cloud of AAA servers, and an
authorizing entity. 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, QoS aware network elements may request
authorization through the AAA cloud based on an incoming QoS reservation
request. The network element will route the request to a designated
authorizing entity. The authorizing entity 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 application servers. After receiving the authorization request from
the application server or the network element, the authorizing entity
decides the appropriate mode (i.e. Push or Pull). The Push or Pull mode
can be dynamically determined based on the information received from the
request of the application server and/or the information (e.g. policy)
in the authorizing entity, or statically configured according to
operator's demand, or the messages between AE and NE. The Authorizing
Entity may identify the access network through the use of some
out-of-band signaling, such as SIP, Diameter, which may be sent from the
application server to Authorizing Entity, and then select appropriate
resource admission and control policies.</t>
<t>If defined properly, the interface between the routers and AAA cloud
would be identical in both cases. Routers are therefore insulated from
the details of particular applications and need not know that
application servers are involved at all. Also, the AAA cloud would
naturally encompass business relationships such as those between network
operators and third-party application providers, enabling 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 for available
resources and determines whether there are enough resources to fulfill
the request. Authorization is performed by the Diameter client
function 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 requested QoS
(depending on the authorization decision). Once the requested resource
is granted, the Resource Management function provides accounting
information to the Authorizing entity using the Diameter client
function.</t>
</section>
<!-- ====================================================================== -->
<section anchor="Implication"
title="Implications of Endpoint QoS Capabilities">
<t></t>
<section title="Category">
<t>The QoS capabilities of endpoints are varied, which can be
categorized as follows: <list style="symbols">
<t>Category 1 endpoint: Has no QoS capability at both
application and network levels. This type of endpoint may set up
a connection through application signaling, but it is unable to
specify any resource/QoS requirements either through application
signaling or does not support network signaling at all.</t>
<t>Category 2 endpoint: Only has QoS capability at the
application level. This type of endpoint is able to set up a
connection through application signaling with certain
resource/QoS requirements (e.g., application attributes), but it
is unable to specify any network level resource/QoS requirements
(e.g., network QoS class) through network signaling e.g., RSVP
or NSIS (or does not support network layer signaling at
all).</t>
<t>Category 3 endpoint: Has QoS capability at the network level.
This type of endpoint may set up a connection through
application signaling and translate service characteristics into
network resource/QoS requirements (e.g., network QoS class)
locally, and request the resources through network signaling,
e.g., RSVP or NSIS.</t>
</list></t>
</section>
<section title="Interaction modes between authorizing entity and network element">
<t>Different QoS mechanisms are employed in packet networks. Those
QoS mechanisms can be categorized into two schemes: IntServ and
DiffServ. In the IntServ scheme, network signaling (e.g., RSVP,
NSIS, or link specific signaling) is commonly used to initiate a
request from endpoint for desired QoS resource of media flow. In the
DiffServ scheme, the QoS resources are provisioned based on some
predefined QoS service classes instead of endpoint initiated per
flow based QoS request.</t>
<t>It is obvious that the eligible QoS scheme is correlated to the
endpoint's capability in the context of QoS authorization. Since
category 1 and 2 endpoints cannot initiate the QoS resource requests
through the network signaling, the IntServ model is not applicable
to them in general. Depending on network technology and
operator’s demand, a category 3 endpoint may either make use
of the network signaling for requesting the resource or not perform
the request.</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 network elements.
When the IntServ scheme is employed by category 3 endpoint, the
authorization process is typically initiated by network element when
a trigger such as the network signaling is received from the
endpoint. In the DiffServ scheme, since the network element is
unable to request the resource authorization on its own initiative,
the authorization process is typically triggered upon either the
request of application servers 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="symbols">
<t>Push mode: The QoS authorization process is triggered by
application servers or local network conditions (e.g., time of
day on resource usage and QoS classes), and the authorization
decisions are installed by the authorizing entity to the network
element on its own initiative without explicit request. In order
to support the push mode, the authorizing entity (i.e., Diameter
server) should be able to initiate a Diameter authorization
session to communicate with the network element (i.e., Diameter
client) without any pre-established connection from the network
element.</t>
<t>Pull mode: The QoS authorization process is triggered by the
network signaling received from end user equipments or by the
local event in the network element according to pre-configured
policies, and authorization decisions are produced upon the
request of the network element. In order to support the pull
mode, the network element (i.e., Diameter client) will initiate
a Diameter authorization session to communicate with authorizing
entity (i.e., Diameter server).</t>
</list></t>
<t>For category 1 and 2 endpoints, the Push mode is required, in
particular, category 1 endpoint requires network initiated push mode
and category 2 endpoint may use both them. For category 3 endpoint,
either push mode or pull mode is doable.</t>
<t>The Push mode is applicable to certain networks, for example,
Cable network, DSL, Ethernet, Diffserv enabled IP/MPLS as defined by
other SDOs, e.g., ETSI TISPAN and ITU-T. The Pull mode is more
appropriate to IntServ enabled IP networks or certain wireless
networks such as GPRS networks as defined by 3GPP/PP2. Some
networks, e.g., WiMAX may require both Push and Pull modes.</t>
</section>
</section>
<section title="Schemes">
<t></t>
<section anchor="authz_models" title="Schemes for pull mode">
<t>Three basic authorization schemes for pull mode exist: one
two-party and two three-party schemes. The notation adopted here is
in respect to the entity that performs the QoS authorization. The
authentication of the QoS requesting entity might be done at the
network element as part of the QoS signaling protocol, or by an
off-path protocol run (on the application layer or for network
access authentication) or the authorizing entity 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 '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>). With the 'two
party scheme' the QoS resource requesting entity is authenticated by
the Network Element and the authorization decision is made either
locally at the Network Element itself or offloaded to a trusted
entity (most likely within the same administrative domain). In the
former case no Diameter QoS protocol interaction is required.</t>
<t><figure anchor="fig-three-party-approach"
title="Three Party Scheme">
<artwork><![CDATA[
+--------------+
| 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>With the 'three party scheme' a QoS reservation request that
arrives at the Network Element is forwarded to the Authorizing
Entity (e.g., in the user's home network), where the authorization
decision is made. 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 Network Element or the Authorizing Entity.</t>
<t>The QoS resource requesting entity may be involved in an
application layer protocol interaction, for example using SIP, with
the Authorizing Entity. 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 Authorizing Entity (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
Network Element 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 the authorization decision performed
at the application layer protocol run to 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 of the Authorizing Entity (for example, of an
application server) 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 Authorizing entity, 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 resource requesting entity where it might receive media
streams, for example in SIP/SDP signalling these port numbers are
advertised. The QoS resource requesting entity 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
Authorizing entity in the QoS authz. request. The Authorizing entity
will use the QoS resource requesting entity'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 authz.
response.</t>
</section>
<section title="Schemes for push mode">
<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 application server upon
explicit QoS request from endpoints through application signaling,
e.g. SIP; in the latter case, the authorization process is triggered
by application server without explicit QoS request from
endpoint.</t>
<t>In the endpoint initiated scheme, the QoS resource requesting
entity (i.e. endpoint) determines the required application level QoS
and sends the QoS request through application signaling message, the
Application Server will extract application level QoS information
and trigger the authorization process to Authorizing entity. In the
network initiated scheme, the Authorizing entity and/or Application
server should derive and determine the QoS requirement according to
application attribute, subscription and endpoint's capability when
the endpoint does not explicitly indicate the QoS attributes. The
authorizing entity makes authorization decision based on application
level QoS information, network policies, end user subscription and
network resource availability etc., and installs the decision to
network element directly.</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
compliant with different deployment scenarios with 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="Inter-domain support"><vspace blankLines="1" /> In
particular, users may roam outside their home network, leading to
a situation where the network element and authorizing entity are
in different administrative domains.<vspace blankLines="1" /></t>
<t hangText="Identity-based Routing"><vspace blankLines="1" /> The
QoS AAA protocol MUST route AAA requests to the Authorizing
Entity, based on the provided identity of the QoS requesting
entity or the identity of the Authorizing entity encoded in the
provided authorization token.<vspace blankLines="1" /></t>
<t hangText="Flexible Authentication Support"><vspace
blankLines="1" /> The QoS AAA protocol 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="1" /> The QoS AAA protocol MUST exchange sufficient
information between the authorizing entity 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="1" /> The QoS AAA protocol MUST allow periodic and
event triggered execution of the authorization process, originated
at the enforcing entity or even at the authorizing entity.<vspace
blankLines="1" /></t>
<t
hangText="Associating QoS Reservations and Application State"><vspace
blankLines="1" /> The QoS AAA protocol MUST carry information
sufficient for an application server to identify the appropriate
application session and associate it with a particular QoS
reservation.<vspace blankLines="1" /></t>
<t hangText="Dynamic Authorization"><vspace blankLines="1" /> It
MUST be possible for the QoS AAA protocol to push updates towards
the network element(s) from authorizing entities.<vspace
blankLines="1" /></t>
<t hangText="Bearer Gating"><vspace blankLines="1" /> The QoS AAA
protocol MUST allow the authorizing entity 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="1" /> The QoS
AAA protocol 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="1" />
The network element 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="1" /> The
QoS AAA protocol MUST allow the network element 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="1" /> The
QoS AAA protocol may support the exchange of sufficient
information to allow for correlation between accounting records
generated by the network elements and accounting records generated
by an application server.<vspace blankLines="1" /></t>
<t hangText="Interaction with other AAA Applications"><vspace
blankLines="1" /> Interaction with other AAA applications such as
Diameter Network Access (NASREQ) application <xref
target="RFC4005"></xref> is 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
Authorizing Entity 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) handshake in
the General Internet Signaling Transport (GIST) protocol, see <xref
target="I-D.ietf-nsis-ntlp"></xref>).</t>
<t>Authentication of the QoS reservation requesting entity to the
Authorizing Entity is necessary if a particular Diameter QoS
application protocol run cannot be related (or if there is no
intention to relate it) to a prior authentication. In this case the
Authorizing Entity 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="1" /> The
time period during which a QoS signaling protocol establishes,
maintains and deletes a QoS reservation state at the QoS network
element is referred 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="1" /> 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="1" />
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 network elements. It
is included in the authorization request message sent to the
Authorizing entity 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 network element correlates the QoS
signaling session with the Diameter authorization sessions. The
Authorizing entity 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 resource requesting entity 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 resource requesting entity may communicate with the
Authorizing Entity 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 Network Element 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 and a tight coupling with these protocols is not
desirable since this applications aims to be generic.</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 Pull mode or Push mode operation is invoked based on the
trigger of QoS Authorization session. When a QAR with a new session ID
is received, the Authorizing Entity operates in the pull mode; when
other triggers are received, the Authorizing Entity operates in the
push mode. Similarly, when a QIR with new session ID is received, the
Network Element operates in the push mode; when other triggers are
received, the Network Element operation in the pull mode.</t>
<section title="Session establishment for pull mode">
<t>A request for a QoS reservation or local events received by a
Network Element can trigger the initiation of a Diameter QoS
authorization session. The Network Element generates a
QoS-Authorization-Request (QAR) message in which it maps required
objects from the QoS signaling message to Diameter payload
objects.</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 Authorizing Entity'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 to the Authorizing Entity. The QAR is sent to
a Diameter server that can either be the home server of the QoS
requesting entity or an application server.</t>
<figure>
<artwork><![CDATA[
+----------------------------------+-------------------------------+
| QoS specific Input Data | Diameter QoS AVPs |
+----------------------------------+-------------------------------+
| Authorizing entity ID (e.g., | Destination-Host |
| taken from authorization token | Destination-Realm |
| or derived based on Network | |
| Access ID (NAI) [RFC4282] | |
| of the QoS requesting entity) | |
+----------------------------------+-------------------------------+
| Authorization Token | QoS-Authz-Data |
| Credentials of | User-Name |
| the QoS requesting entity | |
+----------------------------------+-------------------------------+
| QoS parameters | QoS-Resources |
+----------------------------------+-------------------------------+
]]></artwork>
</figure>
<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">
<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==============....===>|
| |
| +- - - - - QAR - - - - - >|
| |(START,QoS-Resources) |
| | |
| | +--------+--------------+
| | | Report for successful |
| | | QoS reservation |
| | |Update of reserved QoS |
| | | resources |
| | +--------+--------------+
| |< - - - - QAA - - - - - -+
| | |
]]></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 Network Element. The value
DIAMETER_LIMITED_SUCCESS indicates that the Authorizing entity
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 Network Element 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 an 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 Authorizing Entity 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 Authorizing Entity, a Network
Element and a resource requesting entity.</t>
<t>The Network Element'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
Authorizing Entity has knowledge of specific information for
allocating and identifying the Network Element 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 Section 3.2.3 for details.</t>
<figure>
<artwork><![CDATA[
+----------------------------------+-------------------------------+
| QoS specific Input Data | Diameter QoS AVPs |
+----------------------------------+-------------------------------+
| Network Element ID (e.g., from | Destination-Host |
| static configuration | Destination-Realm |
| or dynamically discovered, see | |
| Section 3.2.3 for details) | |
+----------------------------------+-------------------------------+
| Authorization Token | QoS-Authz-Data |
| Credentials of | User-Name |
| the QoS requesting entity | |
+----------------------------------+-------------------------------+
| QoS parameters | QoS-Resources |
+----------------------------------+-------------------------------+
]]></artwork>
</figure>
<t></t>
<t>Authorization processing starts at the Diameter QoS server when
it receives the request from a resource requesting entity through
application server (e.g., SIP Invite) or the trigger by local events
(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">
<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==============....===>|
| |
| (+- - - - - QAR - - - - - >|)
| (|(START,QoS-Resources) |)
| (|< - - - - QAA - - - - - -+)
| | |
]]></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 decision is provided in the
QoS-Resources AVP of the QIR message sent by the Authorizing Entity.
The QoS information provided via the QIR is installed by the QoS
Traffic Control function of the Network Element.</t>
<t>One important piece of information from the Authorizing Entity is
the authorization lifetime (carried inside the QIR). The
authorization lifetime allows the Network Element 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
is 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. When path coupled signaling is used
for QoS reservation along the data path, QAR/QAA may be used to
update the results of QoS reservation and enforcement following the
establishment of data flows.</t>
</section>
<section title="Discovery and selection of peer Diameter QoS application node">
<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 <xref target="RFC3588"></xref>. In
particular, the Network Element shall perform the relevant operation
for Pull mode; the Authorizing Entity shall perform the relevant
operations for Push mode.</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 and based on
some index information provided by the resource requesting entity.
For instance, it can be the Authorization Entity's ID stored in the
authorization token, the end-host's identity (e.g., NAI <xref
target="RFC2486"></xref>) or 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 Authorizing Entity for
re-authorization. These rules depend on the semantics and contents of
the QAA message sent by the Authorizing Entity:</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 Authorizing Entity 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 Authorizing Entity 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 Authorizing Entity.</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 Authorizing entity 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 Authorizing Entity may use RAR 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 Authorizing Entity 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
Authorizing Entity. The transmission of the QAR MAY be triggered,
such as, when the Network Element 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-Authz-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 Authorizing Entity 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 Network Element.</t>
<t>A Network Element 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
Authorizing entity.</t>
<t>If RAR does not include any parameters of the re-authorized QoS
state, the Network Element MUST initiate a QoS re-authorization by
sending a QoS-Authorization-Request (QAR) message towards the
Authorizing entity.</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.
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 |
|<--QoS-Response----+ | session state |
| | +--------+--------------+
|< - - - - STA - - - - - -+
+-------+--------+ |
|Delete QoS state|
+-------+--------+ QoS Responder
| Node
+----------QoS-Reserve-----....--->|
| (Delete QoS |
| reservation) |
|<---------QoS-Response----....----+
| |
]]></artwork>
</figure></t>
</section>
<section title="Server-Side Initiated Session Termination">
<t>At anytime during a session the Authorizing Entity MAY send an
Abort-Session-Request message (ASR) to the Network Element. 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 Network Element 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 Network Element 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="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>
<t><figure>
<artwork><![CDATA[
Command-Name Abbrev. Code Reference
QoS-Authz-Request QAR [TBD] Section 5.1
QoS-Authz-Answer QAA [TBD] Section 5.2
QoS-Install-Request QIR [TBD] Section 5.3
QoS-Install-Answer QIA [TBD] 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>
<t>Diameter nodes conforming to this specification MAY advertise support
by including the value of TBD 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 TBD 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, because these commands are
defined in the Diameter base protocol and no additional mandatory AVPs
for those commands are defined in this document.</t>
<section 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 TBD and 'R' bit set in the Command Flags field is used by
Network elements to request quality of service related resource
authorization for a given flow.</t>
<t>The QAR message MUST carry information for signaling session
identification, Authorizing Entity 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, presented in ABNF form <xref
target="RFC2234"></xref>, is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<QoS-Request> ::= < Diameter Header: XXX, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ Destination-Host ]
[ User-Name ]
* [ QoS-Resources ]
[ QoS-Authz-Data ]
[ Bound-Auth-Session-Id ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section title="QoS-Authorization Answer (QAA)">
<t>The QoS-Authorization-Answer message (QAA), indicated by the
Command- Code field set to TBD 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: XXX, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Request-Type }
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
* [ QoS-Resources ]
[ Acc-Multisession-Id ]
[ Session-Timeout ]
[ Authz-Session-Lifetime ]
[ Authz-Grace-Period ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section title="QoS-Install Request (QIR)">
<t>The QoS-Install Request message (QIR), indicated by the
Command-Code field set to TDB and 'R' bit set in the Command Flags
field is used by Authorizing entity 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: XXX, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ Destination-Host ]
* [ QoS-Resources ]
[ Session-Timeout ]
[ Authz-Session-Lifetime ]
[ Authz-Grace-Period ]
[ Authz-Session-Volume ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section title="QoS-Install Answer (QIA)">
<t>The QoS-Install Answer message (QIA), indicated by the Command-Code
field set to TBD 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: XXX, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Result-Code }
* [ QoS-Resources ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section 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 Authorizing Entity to the Network Element in order to
initiate the QoS re-authorization from DQA server side.</t>
<t>If the RAR command is received by the Network Element without any
parameters of the re-authorized QoS state, the Network Element MUST
initiate a QoS re-authorization by sending a QoS-Authorization-Request
(QAR) message towards the Authorizing entity.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<Re-Auth-Request> ::= < Diameter Header: 258, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ Destination-Host ]
* [ QoS-Resources ]
[ Session-Timeout ]
[ Authz-Session-Lifetime ]
[ Authz-Grace-Period ]
[ Authz-Session-Volume ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
<section 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 Network Element to the Authorizing Entity in response
to the RAR command.</t>
<t>The message format is defined as follows:</t>
<t><figure>
<artwork><![CDATA[
<Re-Auth-Answer> ::= < Diameter Header: 258, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Result-Code }
* [ QoS-Resources ]
* [ AVP ]
]]></artwork>
</figure></t>
</section>
</section>
<!-- ====================================================================== -->
<section anchor="QoS state machine" title="QoS Application State Machine">
<t>The QoS application reuses the authorization state machine defined in
Section 8.1 of the Base Protocol (<xref target="RFC3588"></xref>) with
its own messages as defined in <xref target="messages"></xref> and QoS
AVPs as defined in <xref target="avps"></xref>.</t>
<section anchor="state_supplement"
title="Supplemented states for push mode">
<t>In addition to the reused state machines, the following states are
supplemented to first 2 state machines in which the session state is
maintained on the Server, and 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:</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:</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
Authz-Lifetime 291 Section 8.9
Authz-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-Authz-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|MAY| NOT| NOT|
+----------------------------------------------+----+---+----+-----+
|QoS-Authz-Data TBD 6.4 Grouped | M | P | | V |
|Bound-Auth-Session-Id TBD 6.4 UTF8String | M | P | | 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. |
|P - Indicates the need for encryption for end-to-end security. |
|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-Authz-Data"><vspace blankLines="1" /> The
QoS-Authz-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 Authorizing entity as input to the
computation of the authorization decision. <vspace
blankLines="1" /></t>
<t hangText="Bound-Authentication-Session-Id"><vspace
blankLines="1" /> 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 Network Element 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 Network element 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 Network element
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-Authz-Data ++------------+ |
| >===========>QoS-Resources) |Authorize | |
| | |QoS resources| |
| | ++------------+ |
| | QAA | |
| <- - - - -<<AAA>>- - - -+ |
| |(Result-Code, | |
| |QoS-Resources, | |
| |Authz-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
authorizing entity (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 Authorizing Entity (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-Authz-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 Authorizing entity.</t>
<t>A QAR message will be routed through the AAA network to the
Authorizing Entity. The Authorizing Entity 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 Network element). 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 verifies the accepted QoS against the
pre-authorized QoS resources, and sends a Diameter RAR message to the
DQA client in the network element 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 following:</t>
<t><figure>
<artwork><![CDATA[
Registry:
AVP Code Attribute Name Reference
-----------------------------------------------------------
to be assigned QoS-Authz-Data Section 6.4
to be assigned Bound-Auth-Session-Id Section 6.4
]]></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-Authz-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 using
the next value from the 7-16777215 range. <figure>
<artwork><![CDATA[
Registry:
ID values Name Reference
-----------------------------------------------------------
to be asigned Diameter QoS application Section 5
]]></artwork>
</figure></t>
</section>
<section title="Command Codes">
<t>IANA is requested to allocate command code values for the following
from the range 289-299.</t>
<t><figure>
<artwork><![CDATA[
Registry:
Code Value Name Reference
-----------------------------------------------------------
to be assigned QoS-Authz-Request (QAR) Section 5.1
to be assigned QoS-Authz-Answer (QAA) Section 5.2
to be assigned QoS-Install-Request (QIR) Section 5.3
to be assigned 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. Therefore, it is necessary that
the QoS signaling application to carry sufficient information that
should be forwarded to the backend AAA server. This functionality is
particularly useful in roaming environments where the authorization
decision is most likely provided at an entity where the user can be
authorized, such as in the home realm.</t>
<t>QoS signaling application MAY re-use the authenticated identities
used for the establishment of the secured transport channel for the
signaling messages, e.g., TLS or IPsec between the end host and the
policy aware QoS NE. In addition, a collocation of the QoS NE with, for
example, the Diameter NASREQ application (see <xref
target="RFC4005"></xref>) may allow the QoS authorization to be based on
the authenticated identity used during the network access authentication
protocol run. If a co-located deployment is not desired then special
security protection is required to ensure that arbitrary nodes cannot
reuse a previous authentication exchange to perform an authorization
decision.</t>
<t>Additionally, QoS authorization might be based on the usage of
authorization tokens that are generated by the Authorizing Entity and
provided to the end host via application layer signaling.</t>
<t>The impact of the existence of different authorization models is
(with respect to this Diameter QoS application) the ability to carry
different authentication and authorization information.</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>
</section>
<!-- ====================================================================== -->
<section anchor="contributors" title="Contributors">
<t>The authors would like to thank Tseno Tsenov (tseno.tsenov@gmail.com)
and Frank Alfano (falfano@lucent.com) 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>
<t>[Editor's Note: A bit of history needs to be included here.]</t>
</section>
</middle>
<!-- ====================================================================== -->
<back>
<references title="Normative References">
&RFC2119;
&RFC2234;
&RFC3588;
&RFC4006;
&RFC4005;
&I-D.ietf-dime-qos-attributes;
&I-D.ietf-dime-qos-parameters;
</references>
<references title="Informative References">
&I-D.ietf-nsis-qos-nslp;
&RFC4566;
&RFC2749;
&RFC2210;
&RFC2753;
&RFC4027;
&RFC2865;
&RFC3521;
&RFC3313;
&I-D.ietf-nsis-ntlp;
&RFC3520;
&RFC2486;
</references>
<!-- ====================================================================== -->
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 04:58:15 |