draft-ietf-rap-session-auth-00.txt   draft-ietf-rap-session-auth-01.txt 
RAP Working Group L-N. Hamer RAP Working Group L-N. Hamer
Internet Draft B. Gage Internet Draft B. Gage
Document: draft-ietf-rap-session-auth-00.txt Nortel Networks
Category: Informational April 2001 Document: draft-ietf-rap-session-auth-01.txt Nortel Networks
Category: Informational July 2001
Framework for session set-up with media authorization Framework for session set-up with media authorization
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [1]. all provisions of Section 10 of RFC2026 [1].
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Please send comments to the authors. Please send comments to the authors.
Abstract Abstract
Establishing multimedia streams must take into account requirements Establishing multimedia streams must take into account requirements
for end-to-end QoS, authorization of network resource usage and for end-to-end QoS, authorization of network resource usage and
accurate accounting for resources used. During session set up, accurate accounting for resources used. During session set up,
policies may be enforced to ensure that the media streams being policies may be enforced to ensure that the media streams being
requested lie within the bounds of the service profile established requested lie within the bounds of the service profile established
for the requesting host. Similarly, when a host requests resources for the requesting host. Similarly, when a host requests resources
skipping to change at page 2, line 20 skipping to change at page 2, line 20
Abstract...........................................................1 Abstract...........................................................1
Contents...........................................................2 Contents...........................................................2
1. Introduction....................................................3 1. Introduction....................................................3
2. Conventions used in this document...............................4 2. Conventions used in this document...............................4
3. Definition of terms.............................................5 3. Definition of terms.............................................5
4. The Coupled Model...............................................7 4. The Coupled Model...............................................7
4.1 Coupled Model Message Flows..................................7 4.1 Coupled Model Message Flows..................................7
4.2 Coupled Model Authorization Token............................9 4.2 Coupled Model Authorization Token............................9
4.3 Coupled Model Protocol Impacts...............................9 4.3 Coupled Model Protocol Impacts...............................9
5. The Associated Model <<using One Policy Server>>...............10 5. The Associated Model <<using One Policy Server>>...............10
5.1 Associated Model Message Flows <<using One PS>>.............11 5.1 Associated Model Message Flows <<using One Policy Server>>..11
5.2 Associated Model Authorization Token <<using One PS>>.......12 5.2 Associated Model Authorization Token <<using One PS>>.......12
5.3 Associated Model Protocol Impacts <<using One PS>>..........12 5.3 Associated Model Protocol Impacts <<using One PS>>..........12
5.4 Associated Model Network Impacts <<using One PS>>...........13
6. The Associated Model <<using Two Policy Servers>>..............14 6. The Associated Model <<using Two Policy Servers>>..............14
6.1 Associated Model Message Flows <<using Two PS>>.............15 6.1 Associated Model Message Flows <<using Two PS>>.............15
6.2 Associated Model Authorization Token <<using Two PS>>.......16 6.2 Associated Model Authorization Token <<using Two PS>>.......16
6.3 Associated Model Protocol Impacts <<using Two PS>>..........17 6.3 Associated Model Protocol Impacts <<using Two PS>>..........17
7. The Non-Associated Model.......................................18 7. The Non-Associated Model.......................................18
7.1 Non-Associated Model Call Flow..............................18 7.1 Non-Associated Model Call Flow..............................18
7.2 Non-Associated Model Authorization Token....................20 7.2 Non-Associated Model Authorization Token....................20
7.3 Non-Associated Model Protocol Impacts.......................20 7.3 Non-Associated Model Protocol Impacts.......................20
8. Conclusions....................................................21 8. Conclusions....................................................21
9. Security Considerations........................................22 9. Security Considerations........................................22
References........................................................22 References........................................................22
Acknowledgments...................................................23 Acknowledgments...................................................23
Authors' Addresses................................................23 Authors' Addresses................................................23
Full Copyright Statement..........................................23 Full Copyright Statement..........................................23
Expiration Date...................................................23 Expiration Date...................................................24
Framework for session set-up with media authorization Framework for session set-up with media authorization
1. Introduction 1. Introduction
Establishing multimedia streams must take into account requirements Establishing multimedia streams must take into account requirements
for end-to-end QoS, authorization of network resource usage and for end-to-end QoS, authorization of network resource usage and
accurate accounting for resources used. During session set up, accurate accounting for resources used. During session set up,
policies may be enforced to ensure that the media streams being policies may be enforced to ensure that the media streams being
requested lie within the bounds of the service profile established requested lie within the bounds of the service profile established
for the requesting host. Similarly, when a host requests resources for the requesting host. Similarly, when a host requests resources
to provide a certain QoS for a packet flow, policies may be enforced to provide a certain QoS for a packet flow, policies may be enforced
to ensure that the required resources lie within the bounds of the to ensure that the required resources lie within the bounds of the
resource profile established for the requesting host. resource profile established for the requesting host.
Reference [5] defines a mechanism through which end hosts can use a Reference [5] defines a mechanism through which end hosts can use a
session control protocol (SIP) to indicate that QoS requirements session control protocol (e.g. SIP [10]) to indicate that QoS
must be met in order to successfully set up a session. However, a requirements must be met in order to successfully set up a session.
separate protocol (e.g. RSVP) is used to request the resources However, a separate protocol (e.g. RSVP [11]) is used to request the
required to meet the end-to-end QoS of the media stream. To prevent resources required to meet the end-to-end QoS of the media stream.
fraud and to ensure accurate billing, some linkage is required to To prevent fraud and to ensure accurate billing, some linkage is
verify that the resources being used to provide the requested QoS required to verify that the resources being used to provide the
are in-line with the media streams requested (and authorized) for requested QoS are in-line with the media streams requested (and
the session. authorized) for the session.
This document describes such a linkage through use of a "token" that This document describes such a linkage through use of a "token" that
provides capabilities similar to that of a gate in [8] and of a provides capabilities similar to that of a gate in [8] and of a
ticket in the push model of [2]. The token is generated by a policy ticket in the push model of [2]. The token is generated by a policy
server (or a session manager) and is transparently relayed through server (or a session manager) and is transparently relayed through
the end host to the edge router where it is used as part of the the end host to the edge router where it is used as part of the
policy-controlled flow admission process. policy-controlled flow admission process.
In some environments, authorization of media streams can exploit the In some environments, authorization of media streams can exploit the
fact that pre-established relationships exist between elements of fact that pre-established relationships exist between elements of
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or due to the different business entities involved (e.g. service or due to the different business entities involved (e.g. service
provider and access provider), or due to the dynamic nature of these provider and access provider), or due to the dynamic nature of these
associations (e.g. in a mobile environment). associations (e.g. in a mobile environment).
In this document, we describe these various scenarios and the In this document, we describe these various scenarios and the
mechanisms used for exchanging information between network elements mechanisms used for exchanging information between network elements
in order to authorize the use of resources for a service and to co- in order to authorize the use of resources for a service and to co-
ordinate actions between the session and resource management ordinate actions between the session and resource management
entities. Specific extensions to session control protocols (e.g. SIP entities. Specific extensions to session control protocols (e.g. SIP
[6], H.323), to resource reservation protocols (e.g. RSVP [7], [6], H.323), to resource reservation protocols (e.g. RSVP [7],
YESSIR) and to policy managements protocols (e.g. COPS-SIP, COPS- YESSIR) and to policy managements protocols (e.g. COPS-SIP [12],
RSVP [4]) required to realize these scenarios and mechanisms are COPS-RSVP [4]) required to realize these scenarios and mechanisms
beyond the scope of this document. are beyond the scope of this document.
Framework for session set-up with media authorization Framework for session set-up with media authorization
For clarity, this document will illustrate the media authorization For clarity, this document will illustrate the media authorization
concepts using SIP for session signalling, RSVP for resource concepts using SIP for session signalling, RSVP for resource
reservation and COPS for interaction with the policy servers. Note, reservation and COPS for interaction with the policy servers. Note,
however, that the framework could be applied to a multimedia however, that the framework could be applied to a multimedia
services scenario using different signalling protocols. services scenario using different signalling protocols.
2. Conventions used in this document 2. Conventions used in this document
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4.3 Coupled Model Protocol Impacts 4.3 Coupled Model Protocol Impacts
The use of a media authorization token in the Coupled Model requires The use of a media authorization token in the Coupled Model requires
the addition of new fields to several protocols: the addition of new fields to several protocols:
- Resource reservation protocol. A new protocol field or object - Resource reservation protocol. A new protocol field or object
must be added to the resource reservation protocol to must be added to the resource reservation protocol to
transparently transport the token from the End Host to the Edge transparently transport the token from the End Host to the Edge
Router. The content and internal structure (if any) of this Router. The content and internal structure (if any) of this
object should be opaque to the resource reservation protocol. object should be opaque to the resource reservation protocol. For
example, this is achieved in RSVP with the Policy Data object
defined in [13].
- Policy management protocol. A new protocol field or object must - Policy management protocol. A new protocol field or object must
be added to the policy management protocol to transparently be added to the policy management protocol to transparently
transport the token from the Policy Server to the Session transport the token from the Policy Server to the Session
Management Server and from the Edge Router to the Policy Server. Management Server and from the Edge Router to the Policy Server.
The content and internal structure (if any) of this object should The content and internal structure (if any) of this object should
be opaque to the policy management protocol. be opaque to the policy management protocol. For example, this is
achieved in COPS-RSVP with the Policy Data object defined in
[13].
- Session management protocol. A new protocol field or object must - Session management protocol. A new protocol field or object must
be added to the session management protocol to transparently be added to the session management protocol to transparently
transport the media authorization token from the Session transport the media authorization token from the Session
Management Server to the End Host. The content and internal Management Server to the End Host. The content and internal
structure (if any) of this object should be opaque to the session structure (if any) of this object should be opaque to the session
management protocol. management protocol. For example, this is achieved in SIP with
the proposed header extensions in [6].
Framework for session set-up with media authorization Framework for session set-up with media authorization
5. The Associated Model <<using One Policy Server>> 5. The Associated Model <<using One Policy Server>>
In this scenario, there are multiple instances of the Session In this scenario, there are multiple instances of the Session
Management Servers, Edge Routers and Policy Servers. This leads to a Management Servers, Edge Routers and Policy Servers. This leads to a
network of sufficient complexity that it precludes distributing network of sufficient complexity that it precludes distributing
knowledge of network topology to all network entities. The key knowledge of network topology to all network entities. The key
aspects of this scenario are the following: aspects of this scenario are the following:
- Policy decisions, including media authorization, are made by a - Policy decisions, including media authorization, are made by a
the same Policy Server for both the Session Manager and the Edge the same Policy Server for both the Session Manager and the Edge
Router. Basically, the SCD and RCD outsource policy decisions to Router. However, the Policy Server may change on per-transaction
the same policy server. However, the Policy Server may change on basis.
per-transaction basis.
- The Edge Router, Session Manager and Policy Server involved in - The Edge Router, Session Manager and Policy Server involved in
establishing the session are not known a priori. For example, the establishing the session are not known a priori. For example, the
End Host may be dynamically configured to use one of a pool of End Host may be dynamically configured to use one of a pool of
Session Managers and each of the Session Managers may be Session Managers and each of the Session Managers may be
statically configured to use one of a pool of Policy Servers. statically configured to use one of a pool of Policy Servers.
In another example, the End Host may be mobile and continually In another example, the End Host may be mobile and continually
changing the Edge Router that its point of attachment uses to changing the Edge Router that its point of attachment uses to
communicate with the rest of the network. communicate with the rest of the network.
- There are pre-defined trust relationships between the SMS and the - There are pre-defined trust relationships between the SMS and the
PS and between the ER and the PS. PS and between the ER and the PS.
+---------------------+ +---------+ +---------------------+ +---------+
| SMS ænÆ |<-->| PS æmÆ | | SMS 'n' |<-->| PS 'm' |
+---------------------+ +--------+ | +---------------------+ +--------+ |
+------+ : : : | | | +------+ : : : | | |
| | 1 +--------------------+ 2 | | | | | 1 +--------------------+ 2 | | |
| |-------->| Session Management |----->| | | | |-------->| Session Management |----->| | |
| |<--------| Server 1 |<-----| | | | |<--------| Server 1 |<-----| | |
| | 4 +--------------------+ 3 | | | | | 4 +--------------------+ 3 | | |
| End | | Policy | | | End | | Policy | |
| Host | | Server | | | Host | | Server | |
| | | 1 | | | | | 1 | |
| | 5 +--------------------+ 6 | | | | | 5 +--------------------+ 6 | | |
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within its domain. In order to protect against redirection of within its domain. In order to protect against redirection of
authorization requests to a bogus authorizing entity, the token authorization requests to a bogus authorizing entity, the token
should also include: should also include:
- An authentication signature. This signature is calculated over - An authentication signature. This signature is calculated over
all other fields of the token using an agreed mechanism. The Edge all other fields of the token using an agreed mechanism. The Edge
Router must be able to verify the signature using credentials of Router must be able to verify the signature using credentials of
the signer to confirm a trust relationship. The mechanism used by the signer to confirm a trust relationship. The mechanism used by
the Edge Router is beyond the scope of this document. the Edge Router is beyond the scope of this document.
The detailed semantics of the token are defined in [7].
5.3 Associated Model Protocol Impacts <<using One Policy Server>> 5.3 Associated Model Protocol Impacts <<using One Policy Server>>
The use of a media authorization token in this version of the The use of a media authorization token in this version of the
Associated Model requires the addition of new fields to several Associated Model requires the addition of new fields to several
protocols: protocols:
- Resource reservation protocol. A new protocol field or object - Resource reservation protocol. A new protocol field or object
must be added to the resource reservation protocol to must be added to the resource reservation protocol to
transparently transport the token from the End Host to the Edge transparently transport the token from the End Host to the Edge
Router. The content and internal structure of this object must be Router. The content and internal structure of this object must be
specified so that the Edge Router can distinguish between the specified so that the Edge Router can distinguish between the
elements of the token described in Section 5.2.
Framework for session set-up with media authorization Framework for session set-up with media authorization
elements of the token described in Section 5.2. For example, this
is achieved in RSVP with the Policy Data object defined in [13].
- Policy management protocol. A new protocol field or object must - Policy management protocol. A new protocol field or object must
be added to the policy management protocol to transparently be added to the policy management protocol to transparently
transport the token -- or at least the correlation identifier -- transport the token -- or at least the correlation identifier --
from the Edge Router to the Policy Server. The content and from the Edge Router to the Policy Server. The content and
internal structure of this object should be opaque to the policy internal structure of this object should be opaque to the policy
management protocol. management protocol. For example, this is achieved in COPS-RSVP
with the Policy Data object defined in [13].
- Session management protocol. A new protocol field or object must - Session management protocol. A new protocol field or object must
be added to the session management protocol to transparently be added to the session management protocol to transparently
transport the media authorization token from the Session transport the media authorization token from the Session
Management Server to the End Host. The content and internal Management Server to the End Host. The content and internal
structure of this object should be opaque to the session structure of this object should be opaque to the session
management protocol. management protocol. For example, this is achieved in SIP with
the proposed header extensions in [6].
5.4 Associated Model Network Impacts <<using One Policy Server>>
The use of a media authorization token in this version of the
Associated Model requires that the Edge Router inspect the token to
learn which Policy Server authorized the media. In some
environments, it may not be possible for the Edge Router to perform
this function; in these cases, an Associated Model using Two Policy
Servers (section 6) is required.
This version of the Associated Model also requires that the Edge
Router interact with multiple Policy Servers. Policy decisions are
made by the same Policy Server for both the Session Manager and the
Edge Router, however the Policy Server may change on per-transaction
basis. This implies that the Policy Servers are able to interact
and/or make decisions for the Edge Router in a consistent manner
(e.g. as though there is only a single RCD Policy Server). How this
is accomplished is beyond the scope of this document.
Framework for session set-up with media authorization Framework for session set-up with media authorization
6. The Associated Model <<using Two Policy Servers>> 6. The Associated Model <<using Two Policy Servers>>
In this scenario, there are multiple instances of the Session In this scenario, there are multiple instances of the Session
Management Servers, Edge Routers and Policy Servers. This leads to a Management Servers, Edge Routers and Policy Servers. This leads to a
network of sufficient complexity that it precludes distributing network of sufficient complexity that it precludes distributing
knowledge of network topology to all network entities. The key knowledge of network topology to all network entities. The key
aspects of this scenario are the following: aspects of this scenario are the following:
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Server provided via the Session Manager. Server provided via the Session Manager.
6. The Edge Router intercepts the reservation request and sends a 6. The Edge Router intercepts the reservation request and sends a
policy decision request (e.g. COPS-RSVP REQ) to the RCD Policy policy decision request (e.g. COPS-RSVP REQ) to the RCD Policy
Server in order to determine if the resource reservation request Server in order to determine if the resource reservation request
should be allowed to proceed. Included in this request is the should be allowed to proceed. Included in this request is the
token from the SCD Policy Server provided by the End Host. token from the SCD Policy Server provided by the End Host.
7. The RCD Policy Server uses this token to learn which SCD Policy 7. The RCD Policy Server uses this token to learn which SCD Policy
Server authorized the media. It then sends an authorization Server authorized the media. It then sends an authorization
request (e.g. DIAMETER AA-Request) to that SCD Policy Server in request [3] to that SCD Policy Server in order to determine if
order to determine if the resource reservation request should be the resource reservation request should be allowed to proceed.
allowed to proceed. Included in this request is the token from Included in this request is the token from the SCD Policy Server
the SCD Policy Server provided by the End Host. provided by the End Host.
Framework for session set-up with media authorization Framework for session set-up with media authorization
8. The SCD Policy Server uses this token to correlate the request 8. The SCD Policy Server uses this token to correlate the request
for resources with the media authorization previously provided to for resources with the media authorization previously provided to
the Session Manager. The SCD Policy Server sends a decision (e.g. the Session Manager. The SCD Policy Server sends a decision [3]
DIAMETER AA-Answer) to the RCD Policy Server on whether the to the RCD Policy Server on whether the requested resources are
requested resources are within the bounds authorized by the SCD within the bounds authorized by the SCD Policy Server.
Policy Server.
9. The RCD Policy Server sends a decision (e.g. COPS-RSVP DEC) to 9. The RCD Policy Server sends a decision (e.g. COPS-RSVP DEC) to
the Edge Router, possibly after modifying the parameters of the the Edge Router, possibly after modifying the parameters of the
resources to be reserved. resources to be reserved.
10. The Edge Router, possibly after waiting for end-to-end 10. The Edge Router, possibly after waiting for end-to-end
negotiation for resources to be completed, sends a response to negotiation for resources to be completed, sends a response to
the End Host (e.g. RSVP RESV) indicating that resource the End Host (e.g. RSVP RESV) indicating that resource
reservation is complete or is progressing reservation is complete or is progressing
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Policy Server must be able to verify the signature using Policy Server must be able to verify the signature using
credentials of the signer to confirm a trust relationship. The credentials of the signer to confirm a trust relationship. The
mechanism used by the RCD Policy Server is beyond the scope of mechanism used by the RCD Policy Server is beyond the scope of
this document. this document.
Framework for session set-up with media authorization Framework for session set-up with media authorization
Note that the information in this token is the same as that in Note that the information in this token is the same as that in
Section 5.2 for the "One Policy Server" scenario. Section 5.2 for the "One Policy Server" scenario.
The detailed semantics of the token are defined in [7].
6.3 Associated Model Protocol Impacts <<using Two Policy Servers>> 6.3 Associated Model Protocol Impacts <<using Two Policy Servers>>
The use of a media authorization token in this version of the The use of a media authorization token in this version of the
Associated Model requires the addition of new fields to several Associated Model requires the addition of new fields to several
protocols: protocols:
- Resource reservation protocol. A new protocol field or object - Resource reservation protocol. A new protocol field or object
must be added to the resource reservation protocol to must be added to the resource reservation protocol to
transparently transport the token from the End Host to the Edge transparently transport the token from the End Host to the Edge
Router. The content and internal structure of this object should Router. The content and internal structure of this object should
be opaque to the resource reservation protocol. be opaque to the resource reservation protocol. For example, this
is achieved in RSVP with the Policy Data object defined in [13].
- Policy management protocol. A new protocol field or object must - Policy management protocol. A new protocol field or object must
be added to the policy management protocol to transport the token be added to the policy management protocol to transport the token
from the SCD Policy Server to the Session Management Server and from the SCD Policy Server to the Session Management Server and
from the Edge Router to the RCD Policy Server. The content and from the Edge Router to the RCD Policy Server. The content and
internal structure of this object must be specified so that the internal structure of this object must be specified so that the
Policy Servers can distinguish between the elements of the token Policy Servers can distinguish between the elements of the token
described in Section 6.2. described in Section 6.2. For example, this is achieved in COPS-
RSVP with the Policy Data object defined in [13].
- Session management protocol. A new protocol field or object must - Session management protocol. A new protocol field or object must
be added to the session management protocol to transparently be added to the session management protocol to transparently
transport the media authorization token from the Session transport the media authorization token from the Session
Management Server to the End Host. The content and internal Management Server to the End Host. The content and internal
structure of this object should be opaque to the session structure of this object should be opaque to the session
management protocol. management protocol. For example, this is achieved in SIP with
the proposed header extensions in [6].
Note that these impacts are the same as those discussed in Section Note that these impacts are the same as those discussed in Section
5.3 for the "One Policy Server" scenario. However the use of two 5.3 for the "One Policy Server" scenario. However the use of two
Policy Servers has one additional impact: Policy Servers has one additional impact:
- Authorization protocol. A new protocol field or object must be - Authorization protocol. A new protocol field or object must be
added to the authorization protocol to transport the token from added to the authorization protocol to transport the token from
the RCD Policy Server to the SCD Policy Server. The content and the RCD Policy Server to the SCD Policy Server. The content and
internal structure of this object must be specified so that the internal structure of this object must be specified so that the
Policy Servers can distinguish between the elements of the token Policy Servers can distinguish between the elements of the token
skipping to change at page 20, line 41 skipping to change at page 20, line 41
the token. the token.
- An authentication signature used to prevent tampering with the - An authentication signature used to prevent tampering with the
token and to provide the credentials of the authorizing entity. token and to provide the credentials of the authorizing entity.
This signature is calculated over all other fields of the token This signature is calculated over all other fields of the token
using an agreed mechanism. The RCD Policy Server must be able to using an agreed mechanism. The RCD Policy Server must be able to
verify the signature using credentials of the signer to confirm a verify the signature using credentials of the signer to confirm a
trust relationship. The mechanism used by the RCD Policy Server trust relationship. The mechanism used by the RCD Policy Server
is beyond the scope of this document. is beyond the scope of this document.
The detailed semantics of the token are defined in [7].
7.3 Non-Associated Model Protocol Impacts 7.3 Non-Associated Model Protocol Impacts
The use of a media authorization token in the Non-Associated Model The use of a media authorization token in the Non-Associated Model
requires the addition of new fields to several protocols: requires the addition of new fields to several protocols:
- Resource reservation protocol. A new protocol field or object - Resource reservation protocol. A new protocol field or object
must be added to the resource reservation protocol to must be added to the resource reservation protocol to
transparently transport the token from the End Host to the Edge transparently transport the token from the End Host to the Edge
Router. The content and internal structure of this object should Router. The content and internal structure of this object should
be opaque to the resource reservation protocol. be opaque to the resource reservation protocol. For example, this
is achieved in RSVP with the Policy Data object defined in [13].
- Policy management protocol. A new protocol field or object must
be added to the policy management protocol to transport the token
Framework for session set-up with media authorization Framework for session set-up with media authorization
- Policy management protocol. A new protocol field or object must
be added to the policy management protocol to transport the token
from the SCD Policy Server to the Session Management Server and from the SCD Policy Server to the Session Management Server and
from the Edge Router to the RCD Policy Server. The content and from the Edge Router to the RCD Policy Server. The content and
internal structure of this object must be specified so that the internal structure of this object must be specified so that the
Policy Servers can distinguish between the elements of the token Policy Servers can distinguish between the elements of the token
described in Section 7.2. described in Section 7.2. For example, this is achieved in COPS-
RSVP with the Policy Data object defined in [13].
- Session management protocol. A new protocol field or object must - Session management protocol. A new protocol field or object must
be added to the session management protocol to transparently be added to the session management protocol to transparently
transport the media authorization token from the Session transport the media authorization token from the Session
Management Server to the End Host. The content and internal Management Server to the End Host. The content and internal
structure of this object should be opaque to the session structure of this object should be opaque to the session
management protocol. management protocol. For example, this is achieved in SIP with
the proposed header extensions in [6].
8. Conclusions 8. Conclusions
In this document we have defined three models for authorizing media In this document we have defined three models for authorizing media
during session establishment: during session establishment:
- The Coupled Model which assumes a priori knowledge of network - The Coupled Model which assumes a priori knowledge of network
topology and where pre-established trust relationships exist topology and where pre-established trust relationships exist
between network entities. between network entities.
skipping to change at page 21, line 42 skipping to change at page 21, line 47
- The Non-Associated Model where knowledge of the network topology - The Non-Associated Model where knowledge of the network topology
is not known a priori, where there are different policy servers is not known a priori, where there are different policy servers
involved and where a trust relationship does not exist between involved and where a trust relationship does not exist between
the policy servers. the policy servers.
The Associated Model is applicable to environments where the network The Associated Model is applicable to environments where the network
elements involved in establishing a session have a pre-determined elements involved in establishing a session have a pre-determined
trust relationship but where their identities must be determined trust relationship but where their identities must be determined
dynamically during session set up. The Non-Associated Model is dynamically during session set up. The Non-Associated Model is
applicable to environments where there is a complex network topology applicable to environments where there is a complex network topology
and/or where trust relationships between domains do not exist. and/or where trust relationships between domains do not exist (e.g.
when they are different business entities).
In any given network, one or more of these models may be applicable. In any given network, one or more of these models may be applicable.
Indeed, the model to be used may be chosen dynamically during Indeed, the model to be used may be chosen dynamically during
session establishment based on knowledge of the end points involved session establishment based on knowledge of the end points involved
in the call. In all cases, however, there is no need for the End in the call. In all cases, however, there is no need for the End
Host, the Edge Router or the Session Management Server to understand Host, the Edge Router or the Session Management Server to understand
or interpret the authorization token - to them it is an opaque or interpret the authorization token - to them it is an opaque
Framework for session set-up with media authorization
protocol element that is simply copied from one container protocol protocol element that is simply copied from one container protocol
to another. to another.
Framework for session set-up with media authorization
Finally, the framework defined in this document is extensible to any Finally, the framework defined in this document is extensible to any
kind of session management protocol coupled to any one of a number kind of session management protocol coupled to any one of a number
of resource reservation and/or policy management protocols. of resource reservation and/or policy management protocols.
9. Security Considerations 9. Security Considerations
The purpose of this draft is to describe a mechanism for media The purpose of this draft is to describe a mechanism for media
authorization to prevent theft of service. It does not cover other authorization to prevent theft of service. It does not cover other
possible security breaches such as IP spoofing. possible security breaches such as IP spoofing.
skipping to change at page 22, line 34 skipping to change at page 22, line 36
the End Host. This can be achieved by using digital signatures. the End Host. This can be achieved by using digital signatures.
References References
[1] Bradner, S., "The Internet Standards Process -- Revision 3", [1] Bradner, S., "The Internet Standards Process -- Revision 3",
BCP 9, RFC 2026, October 1996. BCP 9, RFC 2026, October 1996.
[2] J. Vollbrecht et al., "AAA Authorization Framework", RFC 2904, [2] J. Vollbrecht et al., "AAA Authorization Framework", RFC 2904,
August 2000 August 2000
[3] P. Calhoun et al., "DIAMETER Base Protocol", Internet Draft [3] C. de Laat et al., "Generic AAA Architecture", RFC 2903, August
draft-calhoun-diameter-17.txt, September 2000. 2000
[4] S. Herzog et al., "COPS usage for RSVP", RFC 2749, January [4] S. Herzog et al., "COPS usage for RSVP", RFC 2749, January
2000. 2000.
[5] W.Marshall et al. "Integration of Resource Management and SIP", [5] W.Marshall et al. "Integration of Resource Management and SIP",
Internet-Draft, draft-ietf-sip-manyfolks-resource-00, November Internet-Draft, draft-ietf-sip-manyfolks-resource-01, February
2000. 2001, Work in progress.
[6] W. Marshall et al., "SIP Extensions for Media Authorization", [6] W. Marshall et al., "SIP Extensions for Media Authorization",
Internet-Draft, draft-ietf-sip-call-auth-01.txt, February 2001. Internet-Draft, draft-ietf-sip-call-auth-01.txt, February 2001,
Work in progress.
[7] L. Hamer et al. "Session Authorization for RSVP", Internet- [7] L. Hamer et al. "Session Authorization for RSVP", Internet-
Draft, draft-hkg-rap-rsvp-authsession-00.txt, February 2001. Draft, draft-ietf-rap-rsvp-authsession-00.txt, April2001, Work
in progress.
Framework for session set-up with media authorization
[8] "PacketCable Dynamic Quality of Service Specification", [8] "PacketCable Dynamic Quality of Service Specification",
CableLabs, December 1999. CableLabs, December 1999.
http://www.packetcable.com/specs/pkt-sp-dqos-I01-991201.pdf http://www.packetcable.com/specs/pkt-sp-dqos-I01-991201.pdf
Framework for session set-up with media authorization
[9] M. Handley and V. Jacobson, "SDP: session description
protocol," RFC 2327, Apr.1998.
[10] Handley, Schulzrinne, Schooler & Rosenberg, Internet-Draft,
"SIP: Session Initiation Protocol", draft-ietf-sip-rfc2543bis-
03.txt, May 2001, Work in progress.
[11] R. Braden et al.,"Resource ReSerVation protocol (RSVP) --
version 1 functional specification," RFC 2205, Sept.1997.
[12] G. Gross et al., "COPS usage for SIP", Internet-Draft, draft-
gross-cops-sip-01.txt, April 2001, Work in progress.
[13] Herzog, S., "RSVP Extensions for Policy Control", RFC 2750,
January 2000.
Acknowledgments Acknowledgments
The authors would like to thank to following people for their useful The authors would like to thank to following people for their useful
comments and suggestions related to this draft: Doug Reeves, Sam comments and suggestions related to this draft: Doug Reeves, Sam
Christie, Matt Broda, Yajun Liu, Brett Kosinski, Francois Audet, Christie, Matt Broda, Brett Kosinski, Francois Audet,
Jerry Chow, Joe Mierwa, Bill Marshall and many others. Bill Marshall, Kwok Chan and many others.
Authors' Addresses Authors' Addresses
Louis-Nicolas Hamer Louis-Nicolas Hamer
Nortel Networks Nortel Networks
Ottawa, ON Ottawa, ON
CANADA CANADA
Email: nhamer@nortelnetworks.com Email: nhamer@nortelnetworks.com
Bill Gage Bill Gage
skipping to change at page 23, line 34 skipping to change at page 24, line 4
CANADA CANADA
Email: gageb@nortelnetworks.com Email: gageb@nortelnetworks.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved. This Copyright (C) The Internet Society (2001). All Rights Reserved. This
document and translations of it may be copied and furnished to document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
Framework for session set-up with media authorization
kind, provided that the above copyright notice and this paragraph kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be copyrights defined in the Internet Standards process must be
followed, or as required to translate it into. followed, or as required to translate it into.
Expiration Date Expiration Date
This memo is filed as <draft-ietf-rap-session-auth-00.txt>, and This memo is filed as <draft-ietf-rap-session-auth-01.txt>, and
expires September 31, 2001. expires December 31, 2001.
 End of changes. 

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