wdiff draft-ietf-mboned-maccnt-req-04.txt draft-ietf-mboned-maccnt-req-05.txt

Tsunemasa Hayashi, NTT
Internet Draft Haixiang He, Nortel
Document:draft-ietf-mboned-maccnt-req-04.txt
Document:draft-ietf-mboned-maccnt-req-05.txt Hiroaki Satou, NTT
Expires: August 12, 2006
Intended Status: Informational Hiroshi Ohta, NTT
Expires: March 22, 2008 Susheela Vaidya, Cisco Systems

February 8, 2006

September 19, 2007

Requirements for Accounting, Authentication Multicast AAA coordinated between Content
Provider(s) and Authorization in
Well Managed IP Multicasting Services
<draft-ietf-mboned-maccnt-req-04.txt> Network Service Provider(s) <draft-ietf-mboned-
maccnt-req-05.txt>

Status of this Memo
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Copyright (C) The Internet Society (2006) IETF Copyright (C) The IETF Trust (2007). This
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Abstract

This memo presents requirements in the area of accounting and
access control for IP multicasting. The scope of the requirements
is limited to cases that Authentication, Accounting and
Authorization (AAA) functions are coordinated between Content
Provider(s) and Network Service Provider(s). General requirements
for

Hayashi, He, Satou, Ohta and Vaidya [Page 1.] accounting and admission control capabilities including
quality-of-service (QoS) related issues are listed. This memo
assumes that these capabilities can be realized by functions
implemented at edges of a network based on IGMP or MLD. Finally,
cases for Content Delivery Services (CDS) are described as
application examples which could benefit from multicasting
accounting and access control capabilities as described in the I-D. It is proposed that this I-D be used
memo.

This memo defines requirements related to AAA issues for multi-
entity provider models in which the network service provider and
content provider cooperate to provide CDS and various related AAA
functions for purposes such as a
starting point protecting and accounting for further discussion on these issues. the
access to content and network resources. The requirements are
generally not relevant to cases in which there is not a reason to
share AAA functions between separate entities.

Table of Contents

Copyright Notice..................................................1 Notice.................................................1
1. Introduction...................................................2 Introduction..................................................3
2. Definitions and Abbreviations..................................4 Abbreviations.................................5
2.1 Definitions...................................................4 Definitions..................................................5
2.2 Abbreviations.................................................4 Abbreviations................................................6
3. Problem Statement..............................................5 Statement.............................................6
3.1 Accounting Issues............................................5 Issues...........................................6
3.2 Relationship with Secure Multicasting (MSEC).................7 (MSEC)................8
3.3 Regarding Access Media and User Separation...................7 Separation..................8
4. General AAA-related Functional Requirements for IP Multicast...7 Multicasting
.................................................................9
5. Application Example and its Specific Requirements.............13 Requirements............14
5.1 IP Multicast-based Content Delivery Service (CDS): CP and NSP
are different entities (companies)...............................13 (companies)..............................14
5.1.1 Network Model for Multicast Content Delivery Service.......13 Service......15
5.1.2 Content Delivery Service Requirements......................15 Requirements.....................17
5.1.2.1 Accounting Requirements..................................15 Requirements.................................17
5.1.2.2 Authorization Requirements...............................16 Requirements..............................18
5.1.2.3 Authentication Requirements..............................17 Requirements.............................19
5.2 IP Multicast-based Content Delivery Service (CDS): CP and NSP
are the same entities (companies)................................17 (companies)...............................19
6. Acknowledgments...............................................18 Acknowledgments..............................................21
7. IANA Considerations...........................................19 Considerations..........................................21
8. Security Considerations.......................................19 Considerations......................................21
9. Conclusion....................................................19 Privacy considerations.......................................21
10. Conclusion..................................................21
Normative References.............................................19 References............................................22
Authors' Addresses...............................................20 Addresses..............................................23
Full Copyright Statement.........................................21 Statement........................................24
Intellectual Property............................................21 Property...........................................24
Expiration......................................................25
Acknowledgement.................................................25

1. Introduction

This I-D memo will present general functional requirements related to
accounting, authentication access control and authorization admission control issues in IP
multicasting networks. A multicast network which fulfills all of

Hayashi, He, Satou, Ohta and Vaidya [Page 2.]
these requirements will be called a "fully AAA and QoS enabled" IP
multicasting network. Fulfillment of all or some of the
requirements will make possible more robust management of IP
multicasting networks, and as such these capabilities contribute
to the provision of well-managed IP multicasting services. networks.

IP multicasting is becoming widely used as a method to save
network resources such as bandwidth or CPU processing power of the
sender's server for cases where a large volume of information
needs to be distributed to a very large number of receivers. receivers at a
given data speed. This trend can be observed both in enterprise
use and in broadband services provided by network operator/service
providers.

Distance learning within a university and in-house (in-company)
sharing of multimedia information are examples of enterprise use.
In these examples, sources generate high-bit rate (e.g., 6Mbit/s)
streaming information. When the number of receivers becomes
large, such systems do not scale well without multicasting.

On the other hand, a Content Delivery Service (CDS) is an example
of a broadband service provided by network operators/service
providers. Distribution of movies and other video programs to
each user are typical services. Each channel requires large
bandwidth (e.g., 6Mbit/s) and operator/service providers need to
provide many channels to make their service attractive. In
addition, the number of receivers is large (e.g., more than a few
thousands). The system to provide this service does not scale
well without multicasting.

As such, multicasting can be useful to make the network more
scalable when a large volume of information needs to be
distributed to a large number of receivers. However, multicasting
according to current standards (e.g., IGMPv3[1] and MLDv2[2]) has
drawbacks compared to unicasting when one applies it to commercial
services. Accounting of each user's actions is not possible with
multicasting as it is with unicasting. Accounting consists of
grasping each user's behavior, when she/he starts/stops to receive
a channel, which channel she/he receives, etc.

IP multicasting can be used to distribute free material
efficiently, but there

There are limitations to the application of multicasting in usage

Hayashi, He, Satou, Ohta and Vaidya [Page 3.]
models where usage user-based accounting is necessary, such as is the
case with many commercial applications. These limitations have
prevented the widespread deployment of multicasting. Alternatively, one could
develop Development
and use a of proprietary solution solutions to address this issue. such issues is an
alternative to providing standardized solutions. However, non-standard non-
standard solutions have drawbacks in terms of interoperability or
cost of development and maintenance.

Without accounting capability in multicasting, information
providers desiring accounting capability are forced to use
unicasting even when multicasting would otherwise be desirable
from a bandwidth/server resource perspective. If multicasting
could be used with user-based accounting capabilities, its
applicability would be greatly widened.

This I-D memo first describes problems on accounting issues in
multicasting. Then the general requirements for this capability
including QoS related issues are listed. Finally, application
examples which could benefit from multicasting with accounting
capabilities are shown. It is proposed that this I-D be used as a
starting point for a discussion on these issues.

2. Definitions and Abbreviations

2.1 Definitions

Authentication: action for identifying a user as a genuine one.

Authorization: action for giving permission for a user to access
content or the network.

Eligible user: Users may be eligible (permitted) to access
resources because of the attributes they have (e.g., delivery may
require possession of the correct password or digital
certificate), their equipment has (e.g., content may only be
eligible to players that can decode H.264 or 3GPP streams), their edge
access network has (e.g., HD HDTV content may only be eligible to
users with 10 Mbps or faster edge connections), access line), or because of where
they are in network topology (e.g., HD HDTV content may not be
eligible for users across congested links) or in actual geography
(e.g., content may only be

Hayashi, He, Satou, Ohta and Vaidya [Page 4.] licensed for distribution to certain
countries), and, of course, a mix of attributes may be required
for eligibility or ineligibility.

User: In this document user refers to a requester and a recipient
of multicast data, termed a viewer in CDS.

User-based accounting: actions for grasping each user's behavior,
when she/he starts/stops to receive a channel, which channel
she/he receives, etc.

2.2 Abbreviations

AAA: Authentication, Accounting and Authorization

ASM: Any-Source Multicast

CDS: Content Delivery Service

CP: Content Provider

IGMP: Internet Group Management Protocol

MLD: Multicast Listener Discovery

NSP: Network Service Provider

SSM: Single-Source Source Specific Multicast

QoS: Quality of Service

3. Problem Statement

3.1 Accounting Issues

In unicast communications, the server (information source) can
identify the client (information receiver) and only permits
connection by an eligible client when this type of access control
is necessary. In addition, when necessary, the server can grasp
what the client is doing (e.g., connecting to the server, starting
reception, what information the client is receiving, terminating
reception, disconnecting from the server).

Hayashi, He, Satou, Ohta and Vaidya [Page 5.]

On the other hand, in multicast communication with current
standards (e.g., IGMPv3[1] or MLDv2[2]) the server just feeds its
information to the multicast router [as in Fig.1]. Then, the
multicast router replicates the data to any link which has at
least one client requesting the information. In this process,
no eligibility check is conducted. Any client can receive
information just by requesting it. In other words, the

It is envisioned that there are many large-scale content
distribution applications transferred over IP-based networks that
can leverage multicasting technologies to meet their scalability
requirements for clients and data volume, and that some of these
applications require user-based accounting capabilities similar to
available with unicast networks. For example, accounting is needed
if one wants to charge for distributed information on a non-flat-
fee basis. The current standards do not provide multicasting with
authorization or access control capabilities sufficient to meet
the requirements of accounting.

|--- user ----|------------NSP------------------|-----CP---|

+--------+
| user |\
+--------+ \
\+------+ +------+ +------+ +------+
+--------+ |Multi-| |Multi-| |Multi-| | |
| user |---|cast |----|cast |----|cast |----|Server|
+--------+ |router| |router| |router| | |
/+------+ +------+ +------+ +------+
+--------+ /
| user |/
+--------+

Fig.1 Example network for multicast communication

This is the major reason why multicasting is only used for cases
where no user-based accounting capabilities are necessary.
However, since more and more information is transferred over IP-
based networks and some of these applications may require
accounting capabilities, it is easy to envision the requirement of
supporting such cases. For example, accounting is needed if one
wants to charge for distributed information on a non-flat-fee
basis. If the volume of information and number of clients are
large, it is beneficial to use multicasting for purposes of
network resource efficiency.

As such, the same level of user-based accounting capabilities as
provided in unicast networks should be provided in multicast
networks.

Hayashi, He, Satou, Ohta and Vaidya [Page 6.]

3.2 Relationship with Secure Multicasting (MSEC)

In many cases, content encryption (e.g. MSEC) is an effective
method for preventing unauthorized access to original content (in
other words, the ability to decode data to return it to its
generally usable form.) This I-D memo presents requirements for
multicasting networks in the areas of 1) access control to prevent
unauthorized access to the network, usage of network resources (link bandwidth, router's
processing power, etc.) , and 2) accounting to grasp user activity. activity
in a NSP. The functional requirements do not require content
encryption although it might solve some of the content related
problems. At this point, it is not yet clear whether encryption
would be part of a solution and if so, what other components (if
any) would also be required. required. Multicast streams generally consume
large amounts of bandwidth for extended periods of time.
Additionally, some multicast streams may have high-priority
depending on a NSP's policy. NSP does not want to let ineligible
users waste large amounts of bandwidth: for example encryption
protects against content viewing but NSP desires protection
against DoS attacks of ineligible users wasting network resources,
even if it is encrypted. Content encryption and multicast access
control should both be able to coexist for more robust security.

3.3 Regarding Access Media and User Separation

The requirements defined in this memo apply to solutions that
provide user separation either through physical separation
provided by dedicated access media between the user and multicast
router (see Fig. 1) or else through logical separation in cases
of shared physical access media (e.g. using VLAN). However, IP
multicast solutions with shared Layer 2 access media between the
user and multicast router and no logical user separation (e.g.
Ethernet with shared links and no VLAN) are out of scope of this
memo. Nevertheless, some of the requirements in this memo defined
for multicasting may also be relevant to multicasting over links
without either physical or logical user separation. Therefore in
the interest of modularity and flexibility, solutions addressing
the requirements of this memo may also take into account
application to multicasting without such user separation.

4. General AAA-related Functional Requirements for IP Multicasting

In consideration of the issues presented in section 3, the
following requirements have been derived:

(1) User identification

The network should be able to identify each user when they attempt
to access the service so that necessary access controlling actions

Hayashi, He, Satou, Ohta and Vaidya [Page 7.]
can be applied. Also, it is necessary to identify the source
(user) user's
receiver (e.g. IP address) of each request (e.g., join/leave) for user accounting
per host tracking purposes.

With current protocols (IGMP/MLD), the sender cannot distinguish
which receivers (end hosts) are actually receiving the
information. The sender must rely on the information from the
multicasting routers. This can be complicated if the sender and
routers are maintained by different entities.

(2) Issue of Network Resource Protection

In order to guarantee certain QoS it is important for network
providers to be able to protect their network resources from being
wasted, (either maliciously or accidentally).

For comparisons sake, in the case of for unicast this issue can be resolved e.g.
by using RSVP. RSVP in some cases.

(2.1) Access control

The network should be able to apply necessary access controlling
actions when an eligible user requests an action (such as a join
or a leave.) The network should be able to reject any action
requested from an ineligible user.

(2.2) Control mechanism to support bandwidth of multicast stream
from a physical port of edge router or switch
The network may need to control the combined bandwidth for all
groups
channels at the physical port of the edge router or switch so that
these given physical entities are not overflowed with traffic.

(2.3) Control mechanism of number of groups channels delivered from a
physical port of edge router and switch

Hayashi, He, Satou, Ohta and Vaidya [Page 8.]

If an NSP desires to guarantee a certain level of QoS to CP and
the receivers, it is necessary that the NSP be able to control the
number of groups channels delivered from a physical port of an edge
router and a switch so in cases that there is a limit to the combined bandwidth between content
servers and multicast routers number
of packet copies and/or number of channels that can be within the limit. handled by
multicast routers.

For comparisons sake, in the case of for unicast this issue can be resolved e.g.
by using RSVP. RSVP in some cases.

(3) User Authentication

The network should be able to authenticate a user.

(4) User Authorization

The network, at its option, should be able to authorize a user's
access to content or a multicast group, so as to meet any demands
by a CP to prevent content access by ineligible users. In the
case that the NSP may wish to provide a service based on
guaranteed delivery, the NSP would not want to waste its network
resources on ineligible users.

(5) Accounting and Billing

In many commercial multicast situations, NSPs would like to be
able to precisely grasp network resource consumption and CPs would
like to be able to precisely grasp the content consumption by end-
users. Such information might be used for identifying highly
viewed content for advertising revenue, ratings calculations,
programming decisions, etc., as well as billing and auditing
purposes. Also content and network providers may wish to provide
users with access to their usage history.

To assemble such an understanding of end-user user behavior, it is
necessary to precisely log information such as who (host/user) is
accessing what content at what time (join action) until what time
(leave action). The result of the access-control decision (e.g.
results of authorization) would also be valuable information. The

Hayashi, He, Satou, Ohta and Vaidya [Page 9.]
desired degree of logging precisions would depend on the
application used.

(5.1) How to share user information

For commercial multicast applications it is important for NSP and
CP to be able to share information regarding user's behaviour (as
described in (5) in standardized ways.

(6) Notification to Users of the Result of the Join Request

It should be possible to provide information to the user about the
status of his/her join request(granted/denied/other).

(7) Service and Terminal Portability

Depending on the service, networks should allow for a user to
receive a service from different places and/or with a different
terminal device.

(8) Support of ASM and SSM

Both ASM (G), and SSM (S,G) should be supported as multicast
models.

(9) Admission Control for Join Action
In order to maintain a predefined QoS level, depending on the
NSP's policy, an a user edge router should be able to control the number of
streams it serves to a user, and total bandwidth consumed to that
user. For example if the number of streams being served to a
certain user has reached the limit defined by the NSP's policy,
then the user edge router should not accept a subsequent "join" until one
of the existing streams is terminated. Similarly, if the NSP is
controlling by per-user bandwidth consumption, then a subsequent
"join" should not be accepted if delivery of the

Hayashi, He, Satou, Ohta and Vaidya [Page 10.] requested stream
would push the consumed bandwidth over the NSP policy-defined
limit.

(10) Channel Join Latency and Leave Latency

Commercial implementations of IP multicasting are likely to have
strict requirements in terms of user experience. Join latency is
the time between when a user sends a "join" request and when the
requested data streaming first reaches the user. Leave latency is
the time between when a user sends a "leave" signal and when the
network stops streaming to the user.

Leave and Join latencies impact the acceptable end-user user experience for
fast channel surfing. In an IP-TV application, users are not going
to be receptive to a slow response time when changing channels.
If there are policies for controlling the number of simultaneous
streams a user may access then channel surfing will be determined
by the join and leave latencies.

Furthermore, leave affects resource consumption: with a low
"leave latency" network providers could minimize streaming content
when there are no audiences.

It is important that any overhead for authentication,
authorization, and access-control be minimized at the times of
joining and leaving multicast groups channels so as to achieve join and
leave latencies acceptable in terms of user experience. For
example this is important in an IP-TV application, because users
are not going to be receptive to a slow response time when
changing channels.

(11) Scalability

Solutions that are used for well managed AAA and QoS enabled IP multicasting
should scale enough to support the needs of content providers and
network operators. NSP's multicast access and QoS policies should
be manageable for large scale users. (e.g. millions of users,
thousands of edge-routers)

(12) Small Impact on the Existing Products

Hayashi, He, Satou, Ohta and Vaidya [Page 11.]

Impact on the existing products (e.g., protocols, software, etc.)
should be as minimal as possible.

Ideally the NSP should be able to use the same infrastructure
(such as access control) to support commercial multicast services
for the so called "triple play" services: voice (VoIP), video, and
broadband Internet access services.

When a CP requires the NSP to provide a level of QoS surpassing
"best effort" delivery or to provide special services (e.g., to
limited users with specific attributes), certain parameters of the
CDS may be defined by a contractual relation between the NSP and
the CP. However, just as for best-effort unicast, multicast
allows for content sourced by CPs without a contractual relation
with the NSP. Therefore, solutions addressing the requirements
defined in this memo should not make obsolete multicasting without that
does not include AAA features
obsolete. features. NSPs may offer tiered services,
with higher
QOS,accounting, QOS, accounting, authentication, etc., depending on
contractual relation with the CPs. It is therefore important that
Multicast AAA and QoS functions be as modular and flexible as
possible.

(13) Deployable as Alternative to Unicast

IP Multicasting would ideally be available as an alternative to IP
unicasting when the "on-demand" nature of unicasting is not
required. Therefore interfaces to multicasting should allow for
easy integration into CDS systems that support unicasting.

Especially equivalent interfaces for authorization, access control
and accounting capabilities should be provided.

(14) Multicast Replication

The above requirements should also apply if multicast replication
is being done on an access-node (e.g. DSLAMs or OLTs).

Specific functional requirements for each application can be
derived from the above general requirements. An example is shown
in the section 5.

Hayashi, He, Satou, Ohta and Vaidya [Page 12.]

5. Application Example and its Specific Requirements

This section shows an application example which could benefit from
multicasting. Then, specific functional requirements related to
user-based accounting capabilities are derived.

5.1 IP Multicast-based Content Delivery Service (CDS): CP and NSP are
different entities (companies)

Broadband access networks such as ADSL (Asymmetric Digital
Subscriber Line) or FTTH (Fiber to the Home) have been deployed
widely in recent years. Content Delivery Service (CDS) is expected
to be a major application provided through broadband access
networks. Because many services such as television broadcasting
require huge bandwidth (e.g., 6Mbit/s) and processing power at
content server, IP multicast is used as an efficient delivery
mechanism for CDS.

One way to provide high quality CDS is to use closed networks
("walled-garden" model).

This subsection shows an example where CP and NSP are different
entities (companies).

5.1.1 Network Model for Multicast Content Delivery Service

As shown in Fig.2, networks for CDS contain three different types
of entities: Content Provider (CP), Network Service Provider
(NSP), and end user clients. An NSP owns the network resources
(infrastructure). It accommodates content providers on one side
and accommodates end user clients on the other side. NSP provides the
network for CDS to two other entities (i.e., CPs and end user
clients). A CP provides content to each end-user client user through the network
of NSPs. NSPs are responsible for delivering the content to end user
clients, and for controlling the network resources.

Hayashi, He, Satou, Ohta and Vaidya [Page 13.]

+-------------+ +-------------+ +-------------+
| CP | | CP | | CP |
| #1 | | #2 | | #3 |
| +---------+ | | +---------+ | | +---------+ |
| | content | | | | content | | | | content | |
| | server | | | | server | | | | server | |
| +-------+-+ | | +----+----+ | | +-+-------+ |
+----------\--+ +------|------+ +--/----------+
\ | /
\ | / <- network/network
\ | / interface
+------------- \ ------ | ------ / ----+
| \ | / |
| NSP +-+-----+-----+-+ |
| | Provider Edge | |
| +-------+-------+ | +-----------------+
| | |---| Information |
| | | | server |
| +--+------+---+ | +-----------------+
| | User Edge | |
| +--+---+---+--+ |
| / | \ |
+------------- / --- | --- \ ----------+
/ | \
/ | \ <- user/network interface
/ | \
+---------++ +-----+----+ ++---------+
|client #a | |client #b | |client #c |
+----------+ +----------+ +----------+
End user
User A End user User B End user User C

Fig.2 Example of CDS network configuration

The NSP provides the information server for all multicast
channels, and a CP gives detailed channel information (e.g., Time
table of each channel) to the information server. An end-user
client gets the information from the information server. In this
model,
multicast multicasting is used in the NSP's CDS network, and there
are two different contracts. One is the contract between the NSP
and the

Hayashi, He, Satou, Ohta and Vaidya [Page 14.]
end user which permits the user to access the basic network
resources of the NSP. Another contract is between the CP and end user
to permit the user to subscribe to multicast content. Because the
CP and NSP are different entities, and the NSP generally does not
allow a CP to control (operate) the network resources of the NSP,
user authorization needs to be done by the CP and NSP
independently. Since there is no direct connection to the
user/network interface, the CP cannot control the user/network
interface. An end A user may want to move to another place, or may want
to change her/his device (client) anytime any time without interrupting
her/his reception of services. As such, IP Multicast network
should support portability capabilities.

5.1.2 Content Delivery Service Requirements

To have a successful business providing multicast, there

Below are some listed specific requirements to support common business
cases/ contractual arrangements for the IP Multicast-based Content
Delivery Service.

5.1.2.1 Accounting Requirements

Since the CP and

An NSP are may have different contractual agreements with various CPs
or various legal obligations in different locations. One possible
business entities, they need to
share the revenue. Such relationship between a CP and NSP is that of a revenue
sharing business relationship which could be on a per content/usage-base. A solution
should support varied billing and charging methods to satisfy both
common legal and business/financial requirements to deploy
multicasting services: this requires accurate and near real-time
accounting information about the end user clients' activity on accessing
the content services.
The accounting information should be per content/usage-base to
enable varied billing and charging methods.

The user accessing particular content is represented by the user's
activities of joining or leaving the corresponding multicast
group/channel (<g> (<(*,g)> or <s,g>). (s,g)). In multicast networks, only NSPs
can collect group joining or leaving activities in real-time through
their last-hop multicast access edge devices. user edges. The NSPs can transfer the accounting information
to related CPs for them to generate end user billing information. The normal
Existing standard AAA technology
can may be used to transfer the
accounting information.

To match the accounting information with a particular end-user
client, user, the end-user client
user has to be authenticated. Usually the

Hayashi, He, Satou, Ohta and Vaidya [Page 15.] account information of an end-user client a
user for content access is maintained by the CP. An end A user client may have
different user accounts for different CPs. CPs.(e.g. user_a@cp#1 and
user_b@cp#2) The account is usually in the format of (username,
password) so an end user client can access the content services from
anywhere. For example, an end user client can access the CP from different NSPs.
NSPs.(e.g. a fixed line NSP and a mobile NSP). It should be noted
that the user account used for content access can be different
from the one used for network access maintained by NSPs.

The NSP-CP model represents a multi-domain AAA environment. There
are plural cases of the model depending on the trust relationship
between the NSP and CP, and additional service requirements such
as a certain QoS level guarantee or service/terminal portability.

A mechanism is necessary to allow a CP and NSP to grasp each
user's behavior independently.

Another requirement related to accounting is the ability to notify
a user when accounting really starts. When a "free preview"
capability is supported, accounting may not start at the same time
as the user's joining of the stream.

Any solution addressing the requirements of this memo should
consider the Interdomain accounting issues presented in RFC-2975
[3]. It is especially important to consider that the CP and NSP
as separate administrative entities can not be assumed to trust
one another. The solution should be robust enough to handle
packet loss between entity domains and assure for data integrity.
In addition any solution should take into consideration common
legal or financial requirements requiring confidential archiving
of usage data.

5.1.2.2 Authorization Requirements

The NSPs are responsible for delivering content and are generally
required to meet certain QoS levels or SLA (service level
agreements). For example, video quality is very sensitive to packet
loss. So if an NSP cannot meet the quality requirements due --due to limited network resources -- cannot
meet quality requirements if it accepts an additional user request,
the NSP should reject that end user's access request to avoid charging
the existing (i.e., already joined) already-joined) user for bad services. For
example, if an access line is shared by several users, an
additional user's join may cause performance degradation for other
users. If the incoming user is the first user on an edge node, a user edge, this
will initiate the transmission of data between the multicast router provider edge
and the user edge
node and this extra network traffic may cause
performance degradation. There may also be policies that do not
necessarily give highest priority to the "first-come" users, and
these should also be considered.

Hayashi, He, Satou, Ohta and Vaidya [Page 16.]

In order to protect network resources against misuse/malicious
access and maintain a QoS level, appropriate admission control
function for traffic policing purposes is necessary so that the NSP
can accept or reject the request without degrading the QoS beyond
the specified level.

5.1.2.3 Authentication Requirements

There are two different aims of authentication. One is
authentication for network access, and another one is for content
access. For the first case of authentication, NSP has a AAA
server, and for the second case, each CP has a AAA server. In some
cases, CPs delegate (outsource) the operation of user
authentication to NSPs.

As such, in addition to network access, multicast group access by a user
also needs to be authenticated. Content authentication should
support the models where:
- authentication for multicast content is outsourced to the
NSP.
- authentication for multicast content access is operated by
the content provider CP

5.2 IP Multicast-based Content Delivery Service (CDS): CP and NSP are
the same entities (companies)

Another application example is the case where the content provider
(CP) and network service provider (NSP) are the same entity
(company) as shown in Fig. 3. In the case that the CP and NSP are
the same entity, some of the requirements indicated in 4.1 are not
required.

This model does not require the following items:

- Communication method between sender (server) (content server) and user (end
host).
user. Since they belong to the same company, they can use
all the available information.

Hayashi, He, Satou, Ohta and Vaidya [Page 17.]

- Methods to share user-related information between network
providers NSPs and content providers.
CPs.
+-----------------------------------------------------+
| +---------+ |
| | content | |
| | server | |
| +----+----+ |
| | |
| CP+NSP +-------+-------+ |
| | Provider Edge | |
| +-------+-------+ +--------------------+ |
| | | Information server | |
| | +--------------------+ |
| +-------------+ |
| | User Edge | |
| +--+---+---+--+ |
| / | \ |
+----------- / --- | --- \ ---------------------------+
/ | \
/ | \ <- user/network interface
/ | \
+---------++ +-----+----+ ++---------+
|user
|Client #a | |user |client #b | |user |client #c |
+----------+ +----------+ +----------+
End user
User A End user User B End user User C

Fig.3 Example of CDS network configuration
6. Acknowledgments

The authors of this draft would like to express their appreciation
to Pekka Savola of Netcore Ltd., Daniel Alvarez, and Toerless
Eckert of Cisco Systems, Sam Sambasivan of AT&T, Sanjay Wadhwa of
Juniper, Tom Anschutz and Steven Wright of BellSouth, Nicolai
Leymann of T-Systems, Carlos Garcia Braschi of Telefonica
Empresas, Marshall Eubanks of Multicast Techno, Stephen Rife of
NTT and David Meyer in his role as mboned WG chair, as well as
their thanks to the participants of the MBONED WG in general.

Hayashi, He, Satou, Ohta and Vaidya [Page 18.]

Funding for the RFC Editor function is currently provided by the
Internet Society.

7. IANA Considerations

This I-D memo does not raise any IANA consideration issues.

8. Security Considerations

Accounting capabilities can be used to enhance the security of
multicast networks by excluding ineligible clients from the
networks.

These requirements are not meant to address encryption issues.
Any solution meeting these requirements should allow for the
implementation of encryption such as MSEC on the multicast data.

9. Privacy considerations

Any solution which meets these requirements should weigh the
benefits of user-based accounting with the privacy considerations
of the user. For example solutions are encouraged when applicable
to consider encryption of the content data between the content
provider and the user in such a way that the Network Provider does
not know the contents of the channel.

10. Conclusion
This I-D memo describes general requirements for providing "well
managed" AAA and QoS
enabled IP multicasting services. It lists issues related to
accounting, authentication, authorization and admission control
for multicast content delivery. Content Delivery Services with
different business models is are cited as an the type of application
which could benefit from the capabilities of "well managed" AAA and QoS enabled
IP multicasting described in this document.
It is proposed that this document be used as a starting point for
discussing requirements for "well managed" IP multicasting
services.

Normative References

[1] B. Cain, et. al., "Internet Group Management Protocol, Version
3", RFC3376, October 2002.

[2] R. Vida, et. al., "Multicast Listener Discovery Version 2
(MLDv2) for IPv6", RFC3810, June 2004.

Hayashi, He, Satou, Ohta and Vaidya [Page 19.]

[3] Aboba B , et. al., "Introduction to Accounting Management",
RFC 2975, October 2000.

Authors' Addresses

Tsunemasa Hayashi
NTT Network Innovation Laboratories
1-1 Hikarino'oka, Yokosuka-shi, Kanagawa, 239-0847 Japan
Phone: +81 46 859 8790
Email: hayashi.tsunemasa@lab.ntt.co.jp

Haixiang He
Nortel
600 Technology Park Drive Billerica, MA 01801, USA
Phone: +1 978 288 7482
Email: haixiang@nortel.com

Hiroaki Satou
NTT Network Service Systems Laboratories
3-9-11 Midoricho, Musashino-shi, Tokyo, 180-8585 Japan
Phone: +81 422 59 4683
Email: satou.hiroaki@lab.ntt.co.jp

Hiroshi Ohta
NTT Network Service Systems Laboratories
3-9-11 Midoricho, Musashino-shi, Tokyo, 180-8585 Japan
Phone: +81 422 59 3617
Email: ohta.hiroshi@lab.ntt.co.jp

Susheela Vaidya
Cisco Systems, Inc.
170 W. Tasman Drive San Jose, CA 95134
Phone: +1 408 525 1952
Email: svaidya@cisco.com

Hayashi, He, Satou, Ohta and Vaidya [Page 20.]
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Hayashi, He, Satou, Ohta and Vaidya [Page 21.]

Expiration

This Internet-Draft will expire on March 22, 2008.

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