draft-ietf-rap-session-auth-01.txt   draft-ietf-rap-session-auth-02.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-02.txt Nortel Networks
Hugh Shieh
AT&T Wireless
Document: draft-ietf-rap-session-auth-01.txt Nortel Networks Category: Informational November 2001
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].
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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six months and may be updated, replaced, or obsoleted by other six months and may be updated, replaced, or obsoleted by other
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reference material or to cite them other than as "work in progress." reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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The distribution of this memo is unlimited. This memo is filed as The distribution of this memo is unlimited. This memo is filed as
<draft-ietf-rap-session-auth-01.txt>, and expires December 31, 2001. <draft-ietf-rap-session-auth-02.txt>, and expires June 31, 2002.
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
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.
To prevent fraud and to ensure accurate billing, we describe various To prevent fraud and to ensure accurate billing, we describe various
scenarios and mechanisms that provide the linkage required to verify scenarios and mechanisms that provide the linkage required to verify
that the resources being used to provide a requested QoS are in-line that the resources being used to provide a requested QoS are in-line
with the media streams requested (and authorized) for the session. with the media streams requested (and authorized) for the session.
Framework for session set-up with media authorization Framework for session set-up with media authorization
Framework for session set-up with media authorization
Contents Contents
Status of this Memo................................................1 Status of this Memo................................................1
Abstract...........................................................1 Abstract...........................................................1
Contents...........................................................2 Contents...........................................................3
1. Introduction....................................................3 1. Introduction....................................................4
2. Conventions used in this document...............................4 2. Conventions used in this document...............................5
3. Definition of terms.............................................5 3. Definition of terms.............................................6
4. The Coupled Model...............................................7 4. The Coupled Model...............................................8
4.1 Coupled Model Message Flows..................................7 4.1 Coupled Model Message Flows..................................8
4.2 Coupled Model Authorization Token............................9 4.2 Coupled Model Authorization Token...........................10
4.3 Coupled Model Protocol Impacts...............................9 4.3 Coupled Model Protocol Impacts..............................10
5. The Associated Model <<using One Policy Server>>...............10 5. The Associated Model <<using One Policy Server>>...............11
5.1 Associated Model Message Flows <<using One Policy Server>>..11 5.1 Associated Model Message Flows <<using One Policy Server>>..12
5.2 Associated Model Authorization Token <<using One PS>>.......12 5.2 Associated Model Authorization Token <<using One PS>>.......13
5.3 Associated Model Protocol Impacts <<using One PS>>..........12 5.3 Associated Model Protocol Impacts <<using One PS>>..........13
5.4 Associated Model Network Impacts <<using One PS>>...........13 5.4 Associated Model Network Impacts <<using One PS>>...........14
6. The Associated Model <<using Two Policy Servers>>..............14 6. The Associated Model <<using Two Policy Servers>>..............15
6.1 Associated Model Message Flows <<using Two PS>>.............15 6.1 Associated Model Message Flows <<using Two PS>>.............16
6.2 Associated Model Authorization Token <<using Two PS>>.......16 6.2 Associated Model Authorization Token <<using Two PS>>.......17
6.3 Associated Model Protocol Impacts <<using Two PS>>..........17 6.3 Associated Model Protocol Impacts <<using Two PS>>..........18
7. The Non-Associated Model.......................................18 7. The Non-Associated Model.......................................19
7.1 Non-Associated Model Call Flow..............................18 7.1 Non-Associated Model Call Flow..............................19
7.2 Non-Associated Model Authorization Token....................20 7.2 Non-Associated Model Authorization Token....................21
7.3 Non-Associated Model Protocol Impacts.......................20 7.3 Non-Associated Model Protocol Impacts.......................21
8. Conclusions....................................................21 8. Conclusions....................................................22
9. Security Considerations........................................22 9. Security Considerations........................................23
References........................................................22 References........................................................23
Acknowledgments...................................................23 Acknowledgments...................................................24
Authors' Addresses................................................23 Authors' Addresses................................................24
Full Copyright Statement..........................................23 Full Copyright Statement..........................................25
Expiration Date...................................................24 Expiration Date...................................................25
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
skipping to change at page 7, line 51 skipping to change at page 8, line 51
+--------+ +--------+
Figure 2: The Coupled Model Figure 2: The Coupled Model
4.1 Coupled Model Message Flows 4.1 Coupled Model Message Flows
In this model, it is assumed that there is one Policy Server serving In this model, it is assumed that there is one Policy Server serving
both the Service Control and Resource Control districts and that both the Service Control and Resource Control districts and that
there are pre-defined trust relationships between the PS and SMS and there are pre-defined trust relationships between the PS and SMS and
between the PS and ER. Communications between these entities are between the PS and ER. Communications between these entities are
then possible as described below: then possible as described below. Only the originating side flows
are described for simplicity. The same concepts apply to the
terminating side.
Framework for session set-up with media authorization Framework for session set-up with media authorization
1. The End Host issues a session set-up request (e.g. SIP INVITE) to 1. The End Host issues a session set-up request (e.g. SIP INVITE) to
the Session Manager indicating, among other things, the media the Session Manager indicating, among other things, the media
streams to be used in the session. As part of this step, the End streams to be used in the session. As part of this step, the End
Host may authenticate itself to the Session Manager. Host may authenticate itself to the Session Manager.
2. The Session Manager, possibly after waiting for negotiation of 2. The Session Manager, possibly after waiting for negotiation of
the media streams to be completed, sends a policy decision the media streams to be completed, sends a policy decision
skipping to change at page 10, line 42 skipping to change at page 11, line 42
+---------------------+ +---------+ +---------------------+ +---------+
| SMS 'n' |<-->| PS 'm' | | 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 | | | | | ER 'n' | | 1 | |
| | 5 +--------------------+ 6 | | | | | 5 +-+------------------+ | | | |
| |-------->| Edge |----->| | | | |-------->| Edge |-+ 6 | | |
| |<--------| Router |<-----| | | | |<--------| Router |----->| | |
| | 8 +--------------------+ 7 | | | | | 8 +--------------------+ 7 | | |
+------+ | |-+ +------+ <-----| |-+
+--------+ +--------+
Figure 3: The Associated Model using One Policy Server Figure 3: The Associated Model using One Policy Server
Framework for session set-up with media authorization Framework for session set-up with media authorization
5.1 Associated Model Message Flows <<using One Policy Server>> 5.1 Associated Model Message Flows <<using One Policy Server>>
In this model, it is assumed that a Policy Server can make decisions In this model, it is assumed that a Policy Server can make decisions
for both the Service Control and Resource Control districts and that for both the Service Control and Resource Control districts and that
there are pre-defined trust relationships between the PS and SMS and there are pre-defined trust relationships between the PS and SMS and
between the PS and ER. Communications between these entities are between the PS and ER. Communications between these entities are
then possible as described below: then possible as described below. Only the originating side flows
are described for simplicity. The same concepts apply to the
terminating side.
1. The End Host issues a session set-up request (e.g. SIP INVITE) to 1. The End Host issues a session set-up request (e.g. SIP INVITE) to
the Session Manager indicating, among other things, the media the Session Manager indicating, among other things, the media
streams to be used in the session. As part of this step, the End streams to be used in the session. As part of this step, the End
Host may authenticate itself to the Session Manager. Host may authenticate itself to the Session Manager.
2. The Session Manager, possibly after waiting for negotiation of 2. The Session Manager, possibly after waiting for negotiation of
the media streams to be completed, sends a policy decision the media streams to be completed, sends a policy decision
request (e.g. COPS-SIP REQ) to the Policy Server in order to request (e.g. COPS-SIP REQ) to the Policy Server in order to
determine if the session set-up request should be allowed to determine if the session set-up request should be allowed to
skipping to change at page 11, line 43 skipping to change at page 12, line 45
progressing. Included in this response is a description of the progressing. Included in this response is a description of the
negotiated media along with the token from the Policy Server. negotiated media along with the token from the Policy Server.
5. The End Host issues a request (e.g. RSVP PATH) to reserve the 5. The End Host issues a request (e.g. RSVP PATH) to reserve the
resources necessary to provide the required QoS for the media resources necessary to provide the required QoS for the media
stream. Included in this request is the token from the Policy stream. Included in this request is the token from the Policy
Server provided via the Session Manager. Server provided via the Session Manager.
6. The Edge Router intercepts the reservation request and inspects 6. The Edge Router intercepts the reservation request and inspects
the token to learn which Policy Server authorized the media. It the token to learn which Policy Server authorized the media. It
then sends a policy decision request (e.g. COPS-RSVP REQ) to that then sends a policy decision request to that Policy Server in
Policy Server in order to determine if the resource reservation order to determine if the resource reservation request should be
request should be allowed to proceed. Included in this request is allowed to proceed. Included in this request is the token from
the token from the Policy Server provided by the End Host. The the Policy Server provided by the End Host. The Policy Server
Policy Server uses this token to correlate the request for uses this token to correlate the request for resources with the
resources with the media authorization previously provided to the media authorization previously provided to the Session Manager.
Session Manager.
7. The Policy Server sends a decision (e.g. COPS-RSVP DEC) to the 7. The Policy Server sends a decision to the Edge Router, possibly
Edge Router, possibly after modifying the parameters of the after modifying the parameters of the resources to be reserved.
resources to be reserved.
8. The Edge Router, possibly after waiting for end-to-end
negotiation for resources to be completed, sends a response to
Framework for session set-up with media authorization Framework for session set-up with media authorization
8. The Edge Router, possibly after waiting for end-to-end
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.
5.2 Associated Model Authorization Token <<using One Policy Server>> 5.2 Associated Model Authorization Token <<using One Policy Server>>
Since the ER does not know which SMS and PS are involved in session Since the ER does not know which SMS and PS are involved in session
establishment, the token must include: establishment, the token must include:
- A correlation identifier. This is information that the Policy - A correlation identifier. This is information that the Policy
Server can use to correlate the resource reservation request with Server can use to correlate the resource reservation request with
skipping to change at page 12, line 41 skipping to change at page 13, line 44
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]. The detailed semantics of an example 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
specified so that the Edge Router can distinguish between the
Framework for session set-up with media authorization Framework for session set-up with media authorization
Router. The content and internal structure of this object must be
specified so that the Edge Router can distinguish between the
elements of the token described in Section 5.2. For example, this elements of the token described in Section 5.2. For example, this
is achieved in RSVP with the Policy Data object defined in [13]. 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. For example, this is achieved in COPS-RSVP management protocol. For example, this is achieved in COPS-RSVP
with the Policy Data object defined in [13]. with the Policy Data object defined in [13].
skipping to change at page 13, line 38 skipping to change at page 14, line 40
Associated Model requires that the Edge Router inspect the token to Associated Model requires that the Edge Router inspect the token to
learn which Policy Server authorized the media. In some learn which Policy Server authorized the media. In some
environments, it may not be possible for the Edge Router to perform environments, it may not be possible for the Edge Router to perform
this function; in these cases, an Associated Model using Two Policy this function; in these cases, an Associated Model using Two Policy
Servers (section 6) is required. Servers (section 6) is required.
This version of the Associated Model also requires that the Edge This version of the Associated Model also requires that the Edge
Router interact with multiple Policy Servers. Policy decisions are Router interact with multiple Policy Servers. Policy decisions are
made by the same Policy Server for both the Session Manager and the made by the same Policy Server for both the Session Manager and the
Edge Router, however the Policy Server may change on per-transaction Edge Router, however the Policy Server may change on per-transaction
basis. This implies that the Policy Servers are able to interact basis. Note that COPS does not currently allow PEPs to change PDP on
and/or make decisions for the Edge Router in a consistent manner a per-transaction basis. To use this model, a new framework and
(e.g. as though there is only a single RCD Policy Server). How this protocol must be defined for policy decision outsourcing. This model
is accomplished is beyond the scope of this document. also 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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- There is a pre-defined trust relationship between the SMS and the - There is a pre-defined trust relationship between the SMS and the
SCD PS. SCD PS.
- There is a pre-defined trust relationship between the ER and the - There is a pre-defined trust relationship between the ER and the
RCD PS. RCD PS.
- There is a pre-defined trust relationship between the RCD and SCD - There is a pre-defined trust relationship between the RCD and SCD
Policy Servers. Policy Servers.
+--------+ +--------------------+ +--------+
+------+ | | +------+ | SMS ćn╦ | | |
| | 1 +--------------------+ 2 | SCD | | | 1 +-+------------------+ | | SCD |
| |-------->| Session Management |----->| Policy | | |-------->| Session Management |-+ 2 | Policy |
| |<--------| Server |<-----| Server | | |<--------| Server |----->| Server |
| | 4 +--------------------+ 3 | | | | 4 +--------------------+<-----| |
| End | +--------+ | End | 3 +--------+
| | 7 ^ | | | 7 ^ |
| Host | | v 8 | Host | +--------------------+ | v 8
| | +--------+ | | | ER 'n' | +--------+
| | 5 +--------------------+ 6 | | | | 5 +-+------------------+ | | |
| |-------->| Edge |----->| RCD | | |-------->| Edge |-+ 6 | RCD |
| |<--------| Router |<-----| Policy | | |<--------| Router |----->| Policy |
| | 10 +--------------------+ 9 | Server | | | 10 +--------------------+<--- -| Server |
+------+ | | +------+ 9 | |
+--------+ +--------+
Figure 4: The Associated Model using Two Policy Servers Figure 4: The Associated Model using Two Policy Servers
Framework for session set-up with media authorization Framework for session set-up with media authorization
6.1 Associated Model Message Flows <<using Two Policy Servers>> 6.1 Associated Model Message Flows <<using Two Policy Servers>>
In this model, it is assumed that there is one Policy Server for the In this model, it is assumed that there is one Policy Server for the
Service Control District and a different Policy Server for the Service Control District and a different Policy Server for the
Resource Control District. There are pre-defined trust relationships Resource Control District. There are pre-defined trust relationships
between the SCD PS and SMS, between the RCD PS and ER and between between the SCD PS and SMS, between the RCD PS and ER and between
the RCD and SCD Policy Servers. Communications between these the RCD and SCD Policy Servers. Communications between these
entities are then possible as described below: entities are then possible as described below. Only the originating
side flows are described for simplicity. The same concepts apply to
the terminating side.
1. The End Host issues a session set-up request (e.g. SIP INVITE) to 1. The End Host issues a session set-up request (e.g. SIP INVITE) to
the Session Manager indicating, among other things, the media the Session Manager indicating, among other things, the media
streams to be used in the session. As part of this step, the End streams to be used in the session. As part of this step, the End
Host may authenticate itself to the Session Manager. Host may authenticate itself to the Session Manager.
2. The Session Manager, possibly after waiting for negotiation of 2. The Session Manager, possibly after waiting for negotiation of
the media streams to be completed, sends a policy decision the media streams to be completed, sends a policy decision
request (e.g. COPS-SIP REQ) to the SCD Policy Server in order to request (e.g. COPS-SIP REQ) to the SCD Policy Server in order to
determine if the session set-up request should be allowed to determine if the session set-up request should be allowed to
skipping to change at page 17, line 10 skipping to change at page 18, line 10
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]. The detailed semantics of an example 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
skipping to change at page 19, line 4 skipping to change at page 19, line 53
| | 8 +--------------------+ 7 | Server | | | 8 +--------------------+ 7 | Server |
+------+ | | +------+ | |
+--------+ +--------+
Figure 5: The Non-Associated Model Figure 5: The Non-Associated Model
7.1 Non-Associated Model Call Flow 7.1 Non-Associated Model Call Flow
In this model it is assumed that the policy servers make independent In this model it is assumed that the policy servers make independent
decisions for their respective districts, obviating the need for decisions for their respective districts, obviating the need for
information exchange between policy servers. This model also enables
Framework for session set-up with media authorization Framework for session set-up with media authorization
information exchange between policy servers. Communications between session authorization when communication between policy servers is
network entities in this model is described below: not possible for various reasons. It may also be used as a means to
speed up session setup and still ensure proper authorization is
performed.
This model does not preclude the possibility that the policy servers
may communicate at other times for other purposes (e.g. exchange of
accounting information).
Communications between network entities in this model is described
below. Only the originating side flows are described for simplicity.
The same concepts apply to the terminating side.
1. The End Host issues a session set-up request (e.g. SIP INVITE) to 1. The End Host issues a session set-up request (e.g. SIP INVITE) to
the Session Manager indicating, among other things, the media the Session Manager indicating, among other things, the media
streams to be used in the session. As part of this step, the End streams to be used in the session. As part of this step, the End
Host may authenticate itself to the Session Manager. Host may authenticate itself to the Session Manager.
2. The Session Manager, possibly after waiting for negotiation of 2. The Session Manager, possibly after waiting for negotiation of
the media streams to be completed, sends a policy decision the media streams to be completed, sends a policy decision
request (e.g. COPS-SIP REQ) to the SCD Policy Server in order to request (e.g. COPS-SIP REQ) to the SCD Policy Server in order to
determine if the session set-up request should be allowed to determine if the session set-up request should be allowed to
skipping to change at page 19, line 47 skipping to change at page 21, line 5
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 extract information 7. The RCD Policy Server uses this token to extract information
about the media that was authorized by the SCD Policy Server. The about the media that was authorized by the SCD Policy Server. The
RCD Policy Server uses this information in making its decision on RCD Policy Server uses this information in making its decision on
whether the resource reservation should be allowed to proceed. whether the resource reservation should be allowed to proceed.
Framework for session set-up with media authorization
The Policy Server sends a decision (e.g. COPS-RSVP DEC) to the The Policy Server sends a decision (e.g. COPS-RSVP DEC) to the
Edge Router, possibly after modifying the parameters of the Edge Router, possibly after modifying the parameters of the
resources to be reserved. resources to be reserved.
8. The Edge Router, possibly after waiting for end-to-end 8. 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
Framework for session set-up with media authorization
7.2 Non-Associated Model Authorization Token 7.2 Non-Associated Model Authorization Token
In this model, the token must contain sufficient information to In this model, the token must contain sufficient information to
allow the RCD Policy Server to make resource policy decisions allow the RCD Policy Server to make resource policy decisions
autonomously from the SCD Policy Server. The token is created using autonomously from the SCD Policy Server. The token is created using
information about the session received by the SMS. The information information about the session received by the SMS. The information
in the token must include: in the token must include:
- Calling party IP address and port number (e.g. from SDP "c=" - Calling party IP address and port number (e.g. from SDP "c="
skipping to change at page 20, line 44 skipping to change at page 22, line 4
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]. The detailed semantics of the token are defined in [7].
7.3 Non-Associated Model Protocol Impacts 7.3 Non-Associated Model Protocol Impacts
Framework for session set-up with media authorization
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. For example, this be opaque to the resource reservation protocol. For example, this
is achieved in RSVP with the Policy Data object defined in [13]. is achieved in RSVP with the Policy Data object defined in [13].
Framework for session set-up with media authorization
- 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 7.2. For example, this is achieved in COPS- described in Section 7.2. For example, this is achieved in COPS-
RSVP with the Policy Data object defined in [13]. 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
skipping to change at page 21, line 46 skipping to change at page 23, line 4
- 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
Framework for session set-up with media authorization
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 (e.g. and/or where trust relationships between domains do not exist (e.g.
when they are different business entities). 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.
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
skipping to change at page 22, line 43 skipping to change at page 23, line 53
[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] C. de Laat et al., "Generic AAA Architecture", RFC 2903, August [3] C. de Laat et al., "Generic AAA Architecture", RFC 2903, August
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-01, February Internet-Draft, draft-ietf-sip-manyfolks-resource-02, August
2001, Work in progress. 2001, Work in progress.
Framework for session set-up with media authorization
[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-02.txt, August 2001,
Work in progress. 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-ietf-rap-rsvp-authsession-00.txt, April2001, Work Draft, draft-ietf-rap-rsvp-authsession-01.txt, November 2001,
in progress. 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
[9] M. Handley and V. Jacobson, "SDP: session description [9] M. Handley and V. Jacobson, "SDP: session description
protocol," RFC 2327, Apr.1998. protocol," RFC 2327, Apr.1998.
[10] Handley, Schulzrinne, Schooler & Rosenberg, Internet-Draft, [10] Handley, Schulzrinne, Schooler & Rosenberg, Internet-Draft,
"SIP: Session Initiation Protocol", draft-ietf-sip-rfc2543bis- "SIP: Session Initiation Protocol", draft-ietf-sip-rfc2543bis-
skipping to change at page 23, line 30 skipping to change at page 24, line 38
[12] G. Gross et al., "COPS usage for SIP", Internet-Draft, draft- [12] G. Gross et al., "COPS usage for SIP", Internet-Draft, draft-
gross-cops-sip-01.txt, April 2001, Work in progress. gross-cops-sip-01.txt, April 2001, Work in progress.
[13] Herzog, S., "RSVP Extensions for Policy Control", RFC 2750, [13] Herzog, S., "RSVP Extensions for Policy Control", RFC 2750,
January 2000. 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: Kwok Ho Chan, Doug
Christie, Matt Broda, Brett Kosinski, Francois Audet, Reeves, Sam Christie, Matt Broda, Yajun Liu, Brett Kosinski,
Bill Marshall, Kwok Chan and many others. Francois Audet, Bill Marshall, Diana Rawlins 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
Nortel Networks Nortel Networks
Ottawa, ON Ottawa, ON
CANADA CANADA
Email: gageb@nortelnetworks.com Email: gageb@nortelnetworks.com
Framework for session set-up with media authorization
Hugh Shieh
AT&T Wireless
Redmond, WA
USA
Email: hugh.shieh@attws.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-01.txt>, and This memo is filed as <draft-ietf-rap-session-auth-02.txt>, and
expires December 31, 2001. expires June 31, 2002.
 End of changes. 

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