RAP Working Group                                            L-N. Hamer
Internet Draft                                                  B. Gage
Expires August 31, 2002
                                                               M. Broda
Document: draft-ietf-rap-rsvp-authsession-03.txt        Nortel Networks
                                                            B. Kosinski
                                                  University of Alberta
                                                             Hugh Shieh
                                                          AT&T Wireless
                                                           February
                                                              June 2002

                          Session Authorization for RSVP

                   draft-ietf-rap-rsvp-authsession-02.txt

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026 [1]. RFC2026.

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   The distribution of this memo is unlimited. This memo is filed as
   <draft-ietf-rap-rsvp-authsession-02.txt>,
   <draft-ietf rap-rsvp-authsession-03.txt>, and expires August 31, November,
   2002. Please send comments to the authors.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document describes the representation of session authorization
   information in the POLICY_DATA object [POL-EXT] (RFC 2750) for supporting
   policy-based per-session authorization and admission control in
   RSVP.  The goal of session authorization is to allow the exchange of
   information between network elements in order to authorize the use
   of resources for a service and to co-ordinate actions between the
   signaling and transport planes.  This document describes how a
   process on a system authorizes the reservation of resources by a
   host and then provides that host with a session authorization policy
   element which can be inserted into the RSVP PATH message to
   facilitate proper and secure reservation of those resources within
   the network. We describe the encoding of media authorization
   information as RSVP policy elements and provide details relating to
   operations, processing rules and error scenarios.

   Contents

   Status of this Memo................................................1
   Copyright Notice...................................................1
   Abstract...........................................................1
   1. Conventions used in this document...............................3
   2. Introduction....................................................3
   3. Policy Element for Session Authorization Data...................4
   3.1 Policy Data Object Format......................................4
   3.2 Session Authorization Data Policy Element......................4
   3.3 Session Authorization Attributes...............................4
   3.3.1 Authorizing Entity Identifier................................6
   3.3.2 Session Identifier...........................................7
   3.3.3 Source Address...............................................7
   3.3.4 Destination Address..........................................9
   3.3.5 Start time..................................................10
   3.3.6 End time....................................................11
   3.3.7 Resources Authorized........................................11
   3.3.8 Authentication data.........................................12
   4. Integrity of the AUTH_SESSION policy element...................13
   4.1 Shared private keys...........................................13
   4.1.1 Operational Setting using shared private keys...............13
   4.2 Kerberos......................................................14
   4.2.1. Operational Setting using Kerberos.........................14
   4.3 Public Key....................................................15
   4.3.1. Operational Setting for public key based authentication....15
   5. Framework......................................................16
   5.1 The coupled model.............................................16
   5.2 The associated model with one policy server...................16
   5.3 The associated model with two policy servers..................17
   5.4 The non-associated model......................................17
   6. Message Processing Rules.......................................17
   6.1 Message Generation (RSVP Host)................................17
   6.2 Message Reception (Router)....................................18
   6.3 Authorization (Router/PDP)....................................18
   7. Error Signaling................................................18
   8. IANA Considerations............................................19
   9. Security Considerations........................................20
   10. Acknowledgments...............................................21
   11. Normative References..........................................21
   12. Informative References........................................23
   13. Author Information............................................23
   14. Full Copyright Statement......................................24
   15. Notices.......................................................24
   16. RFC Editor Considerations.....................................25

1. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in
   this document are to be interpreted as described in [RFC-2119].

2. Introduction

   RSVP [RFC-2205] is a resource reservation setup protocol designed
   for an integrated services [RFC-1633] or DiffEdge [RFC-2998]
   Internet. Integrated Services over
   Diffserv networks [RFC-2998]. The RSVP protocol is used by a host to
   request specific
   qualities of service services from the network for particular
   application data streams or flows.  RSVP is also used by routers to deliver
   quality-of-service (QoS) requests to all nodes routers along the path(s)
   of the flows and to establish and maintain state to provide the
   requested quality of service.  RSVP requests will generally result
   in resources being reserved in each node router along the data path.
   RSVP allows users to obtain preferential access to network
   resources, under the control of an admission control mechanism.
   Such admission control is often based on user or application
   identity
   [I-REP], [RFC-3182], however, it is also valuable to provide the
   ability for per-session admission control.

   In order to allow for per-session admission control, it is necessary
   to provide a mechanism for ensuring an RSVP request from use of resources by a host has
   been properly pre-authorized authorized before allowing the reservation of those
   resources.  In order to meet this requirement, there must be
   information in the RSVP message which may be used to verify the
   validity of the RSVP request.  This may can be done by providing the
   host with a token upon authorization which may be is inserted into the RSVP
   PATH message and verified by the network.

   We describe

   This document describes the session authorization element
   (AUTH_SESSION) contained in the POLICY_DATA object.  The user
   process must obtain an AUTH_SESSION object from an authorizing
   entity, which it may then
   pass passes to the RSVP process (service) on the
   originating host.  The RSVP service then inserts the AUTH_SESSION
   object into the RSVP PATH message to allow verification of the
   network resource request. Network elements, such as routers, elements verify the request and
   then admit process the RSVP message based on admission policy.

   [S-AUTH] describes a framework in which a session authorization
   policy element may be utilized to contain information relevant to
   the network's decision to grant a reservation request.

3. Policy Element for Session Authorization Data

3.1 Policy Data Object Format

   POLICY_DATA objects contain policy information and are carried by
   RSVP messages. A detail detailed description of the format of POLICY_DATA
   object can be found in "RSVP Extensions for Policy Control" [POL-
   EXT]. [RFC-
   2750].

3.2 Session Authorization Data Policy Element

   In this section we describe a policy element (PE) called session
   authorization data (AUTH_SESSION).  The AUTH_SESSION policy element
   contains a list of fields which describe the session, along with
   other attributes.

          +-------------+-------------+-------------+-------------+
          | Length                    | P-Type = AUTH_SESSION     |
          +-------------+-------------+-------------+-------------+
          // Session Authorization Attribute List                //
          +-------------------------------------------------------+

   Length

   Length: 16 bits
      The length of the policy element (including the Length and
      P-Type) is in number of octets (MUST be in multiples of 4) and
      indicates the end of the session authorization information block.

   P-Type

   P-Type: 16 bits (Session Authorization Type)
      AUTH_SESSION = TBD-by-IANA
      The Policy element type (P-type) of this element.  The
      Internet Assigned Numbers Authority (IANA) acts as a registry
      for policy element types for identity as described in
        [POL-EXT].  The definition for AUTH_SESSION is currently to be
        defined.
      [RFC-2750].

   Session Authorization Attribute List List: variable length
      The session authorization attribute list is a collection of
      objects which describes the session and provides other
      information necessary to verify the RSVP request. An initial set
      of valid objects is described in Section 3.

3.3 Session Authorization Attributes

   A session authorization attribute may contain a variety of
   information and has both an attribute type and subtype.  The
   attribute itself MUST be a multiple of 4 octets in length, and any
   attributes that are not a multiple of 4 octets long MUST be padded
   to a 4-octet boundary. All padding bytes MUST have a value of zero.

      +--------+--------+--------+--------+
      | Length          | S-Type |SubType |
      +--------+--------+--------+--------+
      | Value ...
      +--------+--------+--------+--------+

   Length

   Length: 16 bits
        The length field is two octets and indicates the actual length
        of the attribute (including Length, S-Type and SubType fields)
        in number of octets.  The length does NOT include any bytes
        padding to the value field to make the attribute a multiple of
        4 octets long.

   S-Type

   S-Type: 8 bits
        Session authorization attribute type (S-Type) field is one
        octet.  IANA SHALL act acts as a registry for S-Types as described
        in section 7, IANA Considerations.  Initially, the registry
        contains the following S-Types:

        1  AUTH_ENT_ID          The unique identifier of the entity
                                which authorized the session.

        2  AUTH_ENT_CRED        The credentials of the authorizing
                                    entity, such as a digital
                                    certificate.

            3  SESSION_ID           Unique identifier for this session.

            4

        3  SOURCE_ADDR          Address specification for the
                                session originator.

            5

        4  DEST_ADDR            Address specification for the
                                session end-point.

            6

        5  START_TIME           The starting time for the session.

            7

        6  END_TIME             The end time for the session.

            8

        7  RESOURCES            The resources which the user is
                                authorized to request.

            9  DIGITAL_SIGNATURE    Digital signature

        8  AUTHENTICATION_DATA  Authentication data of the session
                                authorization policy element.

   SubType

   SubType: 8 bits
        Session authorization attribute sub-type is one octet in
        length.  The value of the SubType depends on the S-Type.

   Value

   Value: variable length
        The attribute specific information.

3.3.1 Authorizing Entity Identifier

   AUTH_ENT_ID is used to identify the entity which authorized the
   initial service request and generated the session authorization
   policy element.  The AUTH_ENT_ID may be represented in various
   formats, and the SubType is used to define the format for the ID.
   The format for AUTH_ENT_ID is as follows:

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
      AUTH_ENT_ID

   SubType
      The following sub-types for AUTH_ENT_ID are defined.  IANA
        SHALL act
      acts as a registry for AUTH_ENT_ID sub-types as described
      in section 7, IANA Considerations.  Initially, the registry
      contains the following sub-types of AUTH_ENT_ID:

      1  IPV4_ADDRESS        IPv4 address represented in 32 bits

      2  IPV6_ADDRESS        IPv6 address represented in 128 bits

      3  FQDN                Fully Qualified Domain Name as defined
                             in RFC-1034 as an ASCII string.

      4  ASCII_DN            X.500 Distinguished name as defined
                             in RFC-2253 as an ASCII string.

      5  UNICODE_DN          X.500 Distinguished name as defined
                             in RFC-2253 as a UNICODE string.

      6  URI                 Universal Resource Identifier, as
                             defined in RFC-2396.

      7  KRB_PRINCIPAL      Fully Qualified Kerberos Principal name
                            represented by the ASCII string of a
                            principal followed by the @ realm name as
                            defined in
                                   RFC-1510. RFC-1510 (e.g.
                            principalX@realmY).

      8  KRB_REALM	   Kerberos realm as defined in RFC-1510.

   OctetString
        Contains the authorizing entity identifier.

3.3.2 Authorizing Entity Credentials

   AUTH_ENT_CRED contains the credentials of the authorizing entity,
   which can then be used by the network to ensure that the entity
   which generated this session authorization policy element is a
   valid trusted entity.

   +-------+-------+-------+-------+
   | Length        |S-Type |SubType|
   +-------+-------+-------+-------+
   | OctetString ...
   +-------+-------+-------+-------+

   Length
        Length of the attribute, which MUST be >= 4.

   S-Type
        AUTH_ENT_CRED

   SubType
        The type of credentials contained in this attribute.  IANA
        SHALL act as a registry for AUTH_ENT_CRED sub-types as
        described in section 7, IANA Considerations.  Initially, the
        registry contains the following sub-types:

            1  ASCII_ID      The authorizing entity identification in a
                             plain ASCII text string.

            2  UNICODE_ID    The authorizing entity identification in a
                             plain UNICODE text string.

            3  X509_V3_CERT  A chain  X509_V3_CERT        A chain of authorizing entity's X.509 V3
                             digital certificates.

            4

      9  PGP_CERT            The PGP digital certificate of the
                             authorizing entity.

   OctetString
      Contains the authorizing entity credentials.

3.3.3 identifier.

3.3.2 Session Identifier

   SESSION_ID is a unique identifier for this session. used by the authorizing entity to
   identify the request.  It may be used for a number of purposes,
   including replay detection, or even
   mapping to correlate this request to a policy
   decision entry made by the authorizing entity. The For example, the
   SESSION_ID can be based on simple sequence number or on a standard
   NTP timestamp.

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.
        Dependant on the environment, the session identifier will have
        different lengths in order to ensure uniqueness during the
        lifetime of a token (equal to the lifetime of the session).
        We recommend using an octet string of a minimum of 32 bit, but
        a value of 64 bit may be required in some environments.

   S-Type
      SESSION_ID

   SubType
        The following sub-types
      No subtypes for SESSION_ID SESSION ID are defined.  IANA
        SHALL act as a registry for SESSION_ID sub-types as described
        in section 7, IANA Considerations.  Initially, currently defined; this field MUST
   be set to zero. The authorizing entity is the registry
        contains only network entity
   that needs to interpret the following sub-types contents of SESSION_ID:

            1  ASCII_ID        Simple plain ASCII string identifier.

            2  UNICODE_ID      Simple plain UNICODE string identifier.

            3  OCTET_ID        Raw octet string identifier.

            4  NTP_TIMESTAMP   NTP Timestamp Format as defined in
                               RFC-1305. the SESSION ID therefore the
   contents and format are implementation dependent.

   OctetString
      Contains the actual session identifier.

3.3.4

3.3.3 Source Address

   SOURCE_ADDR is used to identify the source address specification of
   the authorized session. This S-Type MAY may be useful in some scenarios
   to make sure the resource request has been authorized for that
   particular source IP address and/or port.

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+
   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
      SOURCE_ADDR

   SubType
      The following sub types for SOURCE_ADDR are defined. IANA
        SHALL act
      acts as a registry for SOURCE_ADDR sub-types as
      described in section 7, IANA Considerations. Initially, the
      registry contains the following sub types for SOURCE_ADDR:

      1  IPV4_ADDRESS        IPv4 address represented in 32 bits

      2  IPV6_ADDRESS        IPv6 address represented in 128 bits

      3  UDP_PORT            UDP port specification  FQDN                Fully Qualified Domain Name as defined
                             in RFC-1034 as an ASCII string.

      4  TCP_PORT            TCP port specification

   OctetString
        The OctetString  ASCII_DN            X.500 Distinguished name as defined
                             in RFC-2253 as an ASCII string.

      5  UNICODE_DN          X.500 Distinguished name as defined
                             in RFC-2253 as a UNICODE string.

      6  UDP_PORT LIST       list of UDP port specifications,
                             represented as 16 bits per list entry.

      7  TCP_PORT LIST       list of TCP port specifications,
                             represented as 16 bits per list entry.

   OctetString
      The OctetString contains the source address information.

3.3.5

   In scenarios where a source address is required (see Section 5), at
   least one of the subtypes 1 through 5 (inclusive) MUST be included
   in every Session Authorization Data Policy Element. Multiple SOURCE
   ADDR attributes MAY be included if multiple addresses have been
   authorized. The source address field of the RSVP datagram MUST match
   one of the SOURCE ADDR attributes contained in this Session
   Authorization Data Policy Element when resolved to an IP address.

   At most, one instance of subtype 6 MAY be included in every Session
   Authorization Data Policy Element. At most, one instance of subtype
   7 MAY be included in every Session Authorization Data Policy
   Element. Inclusion of a subtype 6 attribute does not prevent
   inclusion of a subtype 7 attribute (i.e. both UDP and TCP ports may
   be authorized).

   If no PORT attributes are specified, then all ports are considered
   valid; otherwise, only the specified ports are authorized for use.

   Every source address and port list must be included in a separate
   SOURCE_ADDR attribute.

3.3.4 Destination Address

   DEST_ADDR is used to identify the destination address of the
   authorized session. This S-Type MAY may be useful in some scenarios to
   make sure the resource request has been authorized for that
   particular destination IP address and/or port.

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
      DEST_ADDR

   SubType
      The following sub types for DEST_ADDR are defined. IANA SHALL
        act
      acts as a registry for DEST_ADDR sub-types as described in
      section 7, IANA Considerations. Initially, the registry
      contains the following sub types for DEST_ADDR:

      1  IPV4_ADDRESS        IPv4 address represented in 32 bits

      2  IPV6_ADDRESS        IPv6 address represented in 128 bits

      3  FQDN                Fully Qualified Domain Name as defined
                             in RFC-1034 as an ASCII string.

      4  ASCII_DN            X.500 Distinguished name as defined
                             in RFC-2253 as an ASCII string.

      5  UNICODE_DN          X.500 Distinguished name as defined
                             in RFC-2253 as a UNICODE string.

      6  UDP_PORT LIST       list of UDP port specification

            4 specifications,
                             represented as 16 bits per list entry.

      7  TCP_PORT LIST       list of TCP port specification specifications,
                             represented as 16 bits per list entry.

   OctetString
      The OctetString contains the destination address specification.

3.3.6 Start time

   START_TIME

   In scenarios where a destination address is used to identify the start time required (see Section
   5), at least one of the authorized
   session. This S-Type MAY subtypes 1 through 5 (inclusive) MUST be useful
   included in some scenarios every Session Authorization Data Policy Element.
   Multiple DEST ADDR attributes MAY be included if multiple addresses
   have been authorized. The destination address field of the RSVP
   datagram MUST match one of the DEST ADDR attributes contained in
   this Session Authorization Data Policy Element when resolved to specify an
   IP address.

   At most, one instance of subtype 6 MAY be included in every Session
   Authorization Data Policy Element. At most, one instance of subtype
   7 MAY be included in every Session Authorization Data Policy
   Element. Inclusion of a subtype 6 attribute does not prevent
   inclusion of a subtype 7 attribute (i.e. both UDP and TCP ports may
   be authorized).

   If no PORT attributes are specified, then all ports are considered
   valid; otherwise, only the specified ports are authorized for use.

   Every destination address and port list must be included in a
   separate DEST_ADDR attribute.

3.3.5 Start time

   START_TIME is used to identify the start time for of the authorized session.
   Session and can be used to prevent replay attacks. If the
   AUTH_SESSION policy element is presented in a resource request, the
   network SHOULD reject the request if it is not received within a few
   seconds of the start time specified.

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
      START_TIME

   SubType
      The following sub types for START_TIME are defined. IANA SHALL
        act
      acts as a registry for START_TIME sub-types as described in
      section 7, IANA Considerations. Initially, the registry
      contains the following sub types for START_TIME:
      1  NTP_TIMESTAMP        NTP Timestamp Format as defined in
                              RFC-1305.

   OctetString
      The OctetString contains the start time.

3.3.7

3.3.6 End time

   END_TIME is used to identify the end time of the authorized
   session. This S-Type MAY
   session and can be useful in some scenarios used to specify a
   end time for limit the amount of time that resources
   are authorized session. for use (e.g. in prepaid session scenarios).

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
      END_TIME

   SubType
      The following sub types for END_TIME are defined. IANA SHALL
        act
      acts as a registry for END_TIME sub-types as described in
      section 7, IANA Considerations. Initially, the registry
      contains the following sub types for END_TIME:

      1  NTP_TIMESTAMP        NTP Timestamp Format as defined in
                              RFC-1305.

   OctetString
      The OctetString contains the end time.

3.3.8

3.3.7 Resources Authorized

   RESOURCES is used to define the characteristics of the authorized
   session. This S-Type MAY may be useful in some scenarios to specify the
   specific resources authorized to ensure the request fits the
   authorized specifications.

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
      RESOURCES

   SubType
      The following sub-types for RESOURCES are defined. IANA SHALL
        act
      acts as a registry for RESOURCES sub-types as described in
      section 7, IANA Considerations. Initially, the registry
      contains the following sub types for RESOURCES:

      1  BANDWIDTH     Maximum bandwidth (kbps) authorized.

      2  FLOW_SPEC     Flow spec specification as defined in
                       RFC-2205.

      3  SDP           SDP Media Descriptor as defined in
                       RFC-2327.

      4  DSCP          Differentiated services codepoint as
                       defined in RFC-2474.

   OctetString
      The OctetString contains the resources specification.

3.3.9 Digital Signature

   In scenarios where a resource specification is required (see Section
   5), at least one of the subtypes 1 through 4 (inclusive) MUST be
   included in every Session Authorization Data Policy Element.
   Multiple RESOURCE attributes MAY be included if multiple types of
   resources have been authorized (e.g. DSCP and BANDWIDTH).

3.3.8 Authentication data

   The DIGITAL_SIGNATURE AUTHENTICATION_DATA attribute contains the digital signature authentication data
   of the AUTH_SESSION policy element and signs all the data in the
   policy element up to the DIGITAL_SIGNATURE. AUTHENTICATION_DATA.  If the
   DIGITAL_SIGNATURE
   AUTHENTICATION_DATA attribute has been included in the AUTH_SESSION
   policy element, it MUST be the last attribute in the list. The
   algorithm used to compute the authentication data depends on the
   AUTH_ENT_ID SubType field. See Section 4 entitled Integrity of the
   AUTH_SESSION policy element.

   A summary of DIGITAL_SIGNATURE AUTHENTICATION_DATA attribute format is described
   below.

      +-------+-------+-------+-------+
      | Length        |S-Type |SubType|
      +-------+-------+-------+-------+
      | OctetString ...
      +-------+-------+-------+-------+

   Length
      Length of the attribute, which MUST be >= > 4.

   S-Type
        DIGITAL_SIGNATURE
      AUTHENTICATION_DATA

   SubType
        The following sub-types
      No sub types for DIGITAL_SIGNATURE AUTHENTICATION_DATA are currently defined. IANA SHALL act as a registry for DIGITAL_SIGNATURE
        sub-types as described in section 7, IANA
        Considerations. Initially, the registry contains the following
        sub types for DIGITAL_SIGNATURE:

            1  DSA_SHA1      DSA signature using SHA1 [X.509].

            2  RSA_SHA1      RSA signature using SHA1 [X.509].

            3  RSA_MD5       RSA signature using MD5 [X.509].

            4  HMAC_SHA1     HMAC with SHA1 [RFC 2104].

            5  HMAC_MD5      HMAC with MD5 [RFC 2104].  This
      field MUST be set to 0.

   OctetString
      OctetString contains the digital signature authentication data of the AUTH_SESSION.

4. Framework

   [S-AUTH] describes a framework in which Integrity of the session authorization AUTH_SESSION policy element may be utilized

   This section describes how to transport information for use in
   authorizing resource reservation for media flows.

5. Message Processing Rules

5.1 Message Generation (RSVP Host)

   An RSVP message ensure the integrity of the policy
   element is created as specified in [RFC-2205] with following
   modifications.

   1. RSVP message preserved.

4.1 Shared private keys

      In shared private key environments, the AUTH_ENT_ID MUST contain at most one be of
   subtypes: IPV4_ADDR, IPV6_ADDR, FQDN, ASCII_DN, UNICODE_DN or URI.
   An example AUTH_SESSION policy element.

   2. A Session Authorization policy element (AUTH_SESSION) is created shown below.

      +--------------+--------------+--------------+--------------+
      | Length                      | P-type = AUTH_SESSION       |
      +--------------+--------------+--------------+--------------+
      | Length                      |SESSION_ID    |     zero     |
      +--------------+--------------+--------------+--------------+
      | OctetString (The session identifier) ...
      +--------------+--------------+--------------+--------------+
      | Length                      |AUTH DATA.    |     zero     |
      +--------------+--------------+--------------+--------------+
      | OctetString (Authentication data) ...
      +--------------+--------------+--------------+--------------+

4.1.1 Operational Setting using shared private keys

   This assumes both the Authorizing Entity and the IdentityType field is set Network router/PDP
   are provisioned with shared private keys and with policies detailing
   which algorithm to indicate be used for computing the identity type
      in authentication data.

   Key maintenance is outside the policy element. Only scope of this document, but
   AUTH_SESSION implementations MUST at least provide the required Session Authorization
      attributes are added.

   3. POLICY_DATA object (containing ability to
   manually configure keys and their parameters locally. The key used
   to produce the AUTH_SESSION policy element) authentication data is inserted in identified by the RSVP message in AUTH_ENT_ID
   field. Each key must also be configured with lifetime parameters for
   the appropriate place.

5.2 Message Reception (Router)

   RSVP message time period within which it is processed valid as specified in [RFC-2205] with following
   modifications.

   1. If router is policy aware then it SHOULD send well as an associated
   cryptographic algorithm parameter specifying the RSVP
      message algorithm to be
   used with the PDP and wait key. At a minimum, all AUTH_SESSION implementations
   MUST support the HMAC-MD5-96 [RFC-2104][FRC-1321] cryptographic
   algorithm for response. If computing the router authentication data.

   It is
      policy unaware then it ignores the policy data objects and
      continues processing the RSVP message.

   2. Reject good practice to regularly change keys. Keys MUST be
   configurable such that their lifetimes overlap allowing smooth
   transitions between keys. At the message if midpoint of the response lifetime overlap
   between two keys, senders should transition from using the PDP is negative.

   3. Continue processing the RSVP message.

5.3 Authorization (Router/PDP)

   1. Retrieve the AUTH_SESSION policy element. Check current
   key to the PE type
      field next/longer-lived key. Meanwhile, receivers simply accept
   any identified key received within its configured lifetime and return an error if
   reject those that are not.

4.2 Kerberos

   In a Kerberos environment, the identity type is not supported.

   2. Verify AUTH_ENT_ID MUST be of the authorizing entity credentials and message integrity. subtype
   KRB_PRINCIPAL. Kerberos [RFC 1510] authentication uses a trusted
   third party (the Kerberos Distribution Center - Pre-shared key authentication: Get entity ID, identify
        appropriate pre-shared key KDC) to provide for
   authentication of the authorizing entity, AUTH_SESSION to a network server.  It is
   assumed that a KDC is present and
        validate signature.

      - Public Key: Validate the certificate chain against
        trusted Certificate Authority (CA) both host and valide verifier of
   authentication information (authorizing entity and router/PDP)
   implement Kerberos authentication.

   An example of the
        message signature Kerberos AUTH_DATA policy element is shown below.

      +--------------+--------------+--------------+--------------+
      | Length                      | P-type = AUTH_SESSION       |
      +--------------+--------------+--------------+--------------+
      | Length                      |SESSION_ID    |     zero     |
      +--------------+--------------+--------------+--------------+
      | OctetString (The session identifier) ...
      +--------------+--------------+--------------+--------------+
      | Length                      | AUTH_ENT_ID  | KERB_P.      |
      +--------------+--------------+--------------+--------------+
      | OctetString (The principal@realm name) ...
      +--------------+--------------+--------------+--------------+

4.2.1. Operational Setting using Kerberos

      An authorizing entity is configured to construct the AUTH_SESSION
   policy element that designates use of the public key.

      - Kerberos Ticket: Request authentication
   method (KRB_PRINCIPAL).  Upon reception of the RSVP request, the
   router/PDP contacts the local KDC to request a ticket for the
   authorizing entity
        from the local KDC. Use (principal@realm). The router/PDP uses the ticket
   to access the authorizing entity and obtain authentication data for
   the message (e.g. message.

   For cases where the authorizing entity is in a different realm (i.e.
   administrative domain, organizational boundary), the router/PDP
   needs to fetch a cross-realm Ticket Granting Ticket (TGT) from its
   local KDC. This TGT can be used to fetch authorizing entity tickets
   from the KDC in the remote realm. Note that for performance
   considerations, tickets are typically cached for extended periods.

4.3 Public Key

      In a public key environment, the AUTH_ENT_ID MUST be of the
   subtypes: X509_V3_CERT or PGP_CERT. The authentication data is used
   for authenticating the authorizing entity.  An example of the public
   key AUTH_SESSION policy element is shown below.

      +--------------+--------------+--------------+--------------+
      | Length                      | P-type = AUTH_SESSION       |
      +--------------+--------------+--------------+--------------+
      | Length                      |SESSION_ID    |     zero     |
      +--------------+--------------+--------------+--------------+
      | OctetString (The session identifier) ...
      +--------------+--------------+--------------+--------------+
      | Length                      | AUTH_ENT_ID  |   PGP_CERT   |
      +--------------+--------------+--------------+--------------+
      | OctetString (Authorizing entity Digital Certificate) ...
      +--------------+--------------+--------------+--------------+
      | Length                      |AUTH DATA.    |     zero     |
      +--------------+--------------+--------------+--------------+
      | OctetString (Authentication data) ...
      +--------------+--------------+--------------+--------------+

4.3.1. Operational Setting for public key based authentication

      Public key based authentication assumes following:

         -  Authorizing entities have a pair of keys (private key and
            public key).

         -  Private key is secured with the authorizing entity.

         -  Public keys are stored in digital certificates and a
            trusted party, certificate authority (CA) issues these
            digital certificates.

         -  The verifier (PDP or router) has the ability to verify the
            digital certificate.

   Authorizing entity uses its private key to generate
   AUTHENTICATION_DATA. Authenticators (router, PDP) use the
   authorizing entity's public key (stored in the digital certificate)
   to verify and authenticate the policy element.

5. Framework

   [S-AUTH] describes a framework in which the AUTH_SESSION
   policy element may be utilized to transport information required for
   authorizing resource reservation for media flows. [S-AUTH]
   introduces 4 different models:
   1- the coupled model
   2- the associated model with one policy server
   3- the associated model with two policy servers
   4- the non-associated model.

   The fields that are required in an AUTH SESSION policy element is
   dependent on which of the models is used.

5.1 The coupled model

   In the Coupled Model, the only information that MUST be included in
   the policy element is the SESSION ID; it is used by the Authorizing
   Entity to correlate the resource reservation request with the media
   authorized during session set up. Since the End Host is assumed to
   be untrusted, the Policy Server SHOULD take measures to ensure that
   the integrity of the SESSION ID is preserved in transit; the exact
   mechanisms to be used and the format of the SESSION ID are
   implementation dependent.

5.2 The associated model with one policy server

   In this model, the contents of the AUTH_SESSION policy element MUST
   include:

   -  A session identifier - SESSION_ID. This is information that the
      authorizing entity can use to correlate the resource reservation
      request with the media authorized during session set up.

   -  The identity of the authorizing entity _ AUTH_ENT_ID. This
      information is used by the Edge Router to determine which
      authorizing entity (Policy Server) should be used to solicit
      resource policy decisions.

   In some environments, an Edge Router may have no means for
   determining if the identity refers to a legitimate Policy Server
   within its domain. In order to protect against redirection of
   authorization requests to a bogus authorizing entity, the
   AUTH_SESSION MUST also include:

   -  AUTHENTICATION_DATA. This authentication data is calculated over
      all other fields of the AUTH_SESSION policy element.

5.3 The associated model with two policy servers

   The content of the AUTH_SESSION Policy Element is identical to the
   associated model with one policy server.

5.4 The non-associated model

   In this model, the AUTH_SESSION MUST contain sufficient information
   to allow the Policy Server to make resource policy decisions
   autonomously from the authorizing entity. The policy element is
   created using information about the session by the authorizing
   entity. The information in the AUTH_SESSION policy element MUST
   include:

   -  Calling party IP address or Identity (e.g. FQDN) - SOURCE_ADDR S-
      TYPE
   -  Called party IP address or Identity (e.g. FQDN) - DEST_ADDR S-
      TYPE
   -  The characteristics of (each of) the media stream(s) authorized
      for this session - RESOURCES S-TYPE
   -  The authorization lifetime - START_TIME S-TYPE
   -  The identity of the authorizing entity to allow for validation of
      the token in shared private key and Kerberos schemes -
      AUTH_ENT_ID S-TYPE
   -  The credentials of the authorizing entity in a public-key scheme
      - AUTH_ENT_ID S-TYPE
   -  Authentication data used to prevent tampering with the
      AUTH_SESSION policy element - AUTHENTICATION_DATA

   Furthermore, the AUTH_SESSION policy element MAY contain:

   -  The lifetime of (each of) the media stream(s) - END_TIME S-TYPE
   -  Calling party port number - SOURCE_ADDR S-TYPE
   -  Called party port number - DEST_ADDR S-TYPE

   All AUTH_SESSION fields MUST match with the resource request. If a
   field does not match, the request SHOULD be denied.

6. Message Processing Rules

6.1 Message Generation (RSVP Host)

   An RSVP message is created as specified in [RFC-2205] with following
   modifications.

   1. RSVP message MUST contain at most one AUTH_SESSION policy
   element.

   2. A Session Authorization policy element (AUTH_SESSION) is created
   and the IdentityType field is set to indicate the identity type
   in the policy element. Only the required Session Authorization
   attributes are added.

   3. POLICY_DATA object (containing the AUTH_SESSION policy element)
   is inserted in the RSVP message in the appropriate place.

6.2 Message Reception (Router)

   RSVP message is processed as specified in [RFC-2205] with following
   modifications.

   1. If router is policy aware then it SHOULD send the RSVP
   message to the PDP and wait for response. If the router is
   policy unaware then it ignores the policy data objects and
   continues processing the RSVP message.

   2. Reject the message if the response from the PDP is negative.

   3. Continue processing the RSVP message.

6.3 Authorization (Router/PDP)

   1. Retrieve the AUTH_SESSION policy element. Check the PE type
   field and return an error if the identity type is not supported.

   2. Verify the message integrity.

   - Shared private key authentication: Get authorizing entity ID,
     identify appropriate algorithm and shared private key for the
     authorizing entity, and validate signature.

   - Public Key: Validate the certificate chain against
     trusted Certificate Authority (CA) and validate the
     message signature using the public key.

   - Kerberos Ticket: If the AUTH_ENT_ID is of subtype KRB_PRINCIPAL,
     Request a ticket for the authorizing entity (principal@realm)
     from the local KDC. Use the ticket to access the authorizing
     entity and obtain authentication data for the message.

   3. Verify the requested resources do not exceed the authorized QoS.

7. Error Signaling

   If a PDP fails to verify the AUTH_SESSION policy element then it
   MUST return a policy control failure (Error Code = 02) to the PEP.
   The error values are described in [RFC-2205] and [RFC-2750]. Also
   the PDP SHOULD supply a policy data object containing an AUTH_DATA
   Policy Element with A-Type=POLICY_ERROR_CODE containing more
   details on the Policy Control failure [RFC-3182]. The PEP
   MUST include this Policy Data object in the outgoing RSVP Error
   message.

8. IANA Considerations

   Following the policies outlined in [IANA-CONSIDERATIONS], Standard
   RSVP Policy Elements (P-type values) are assigned by IETF Consensus
   action as described in [RFC-2750].

   P-Type AUTH_SESSION is assigned the value TBD-by-IANA.

   Following the policies outlined in [IANA-CONSIDERATIONS], session
   authorization attribute types (S-Type)in the range 0-127 are
   allocated through an IETF Consensus action; S-Type values between
   128-255 are reserved for Private Use and are not assigned by IANA.

   S-Type AUTH_ENT_ID is assigned the value 1.
   S-Type SESSION_ID is assigned the value 2.
   S-Type SOURCE_ADDR is assigned the value 3.
   S-Type DEST_ADDR is assigned the value 4.
   S-Type START_TIME is assigned the value 5.
   S-Type END_TIME is assigned the value 6.
   S-Type RESOURCES is assigned the value 7.
   S-Type AUTHENTICATION_DATA is assigned the value 8.

   Following the policies outlined in [IANA-CONSIDERATIONS],
   AUTH_ENT_ID SubType values in the range 0-127 are allocated through
   an IETF Consensus action, SubType values between 128-255 are
   reserved for Private Use and are not assigned by IANA.

   AUTH_ENT_ID SubType IPV4_ADDRESS is assigned the value 1.
   SubType IPV6_ADDRESS is assigned the value 2.
   SubType FQDN is assigned the value 3.
   SubType ASCII_DN is assigned the value 4.
   SubType UNICODE_DN is assigned the value 5.
   SubType URI is assigned the value 6.
   SubType KRB_PRINCIPAL is assigned the value 7.
   SubType X509_V3_CERT is assigned the value 8.
   SubType PGP_CERT is assigned the value 9.

   Following the policies outlined in [IANA-CONSIDERATIONS],
   SOURCE_ADDR SubType values in the range 0-127 are allocated through
   an IETF Consensus action, SubType values between 128-255 are
   reserved for Private Use and are not assigned by IANA.

   SOURCE_ADDR SubType IPV4_ADDRESS is assigned the value 1.
   SubType IPV6_ADDRESS is assigned the value 2.
   SubType FQDN is assigned the value 3.
   SubType ASCII_DN is assigned the value 4.
   SubType UNICODE_DN is assigned the value 5.
   SubType UDP_PORT_LIST is assigned the value 6.

   SubType TCP_PORT_LIST is assigned the value 7.

   Following the policies outlined in [IANA-CONSIDERATIONS],
   DEST_ADDR SubType values in the range 0-127 are allocated through an
   IETF Consensus action, SubType values between 128-255 are reserved
   for Private Use and are not assigned by IANA.

   DEST_ADDR SubType IPV4_ADDRESS is assigned the value 1.
   SubType IPV6_ADDRESS is assigned the signing key) or value 2.
   SubType FQDN is assigned the data itself. value 3. Verify
   SubType ASCII_DN is assigned the requested QoS does not exceed value 4.
   SubType UNICODE_DN is assigned the authorized QoS. value 5.
   SubType UDP_PORT_LIST is assigned the value 6. Error Signaling

   If PDP fails to verify
   SubType TCP_PORT_LIST is assigned the AUTH_SESSION policy element then it MUST
   return policy control failure (Error Code = 02) to value 7.

   Following the PEP. The
   error policies outlined in [IANA-CONSIDERATIONS],
   START_TIME SubType values are described in [RFC-2205] and [POL-EXT]. Also PDP
   SHOULD supply a policy data object containing an AUTH_DATA
   Policy Element with A-Type=POLICY_ERROR_CODE containing more
   details on the Policy Control failure [I-REP]. The PEP
   will include this Policy Data object in range 0-127 are allocated through
   an IETF Consensus action, SubType values between 128-255 are
   reserved for Private Use and are not assigned by IANA.

   START_TIME SubType NTP_TIMESTAMP is assigned the outgoing RSVP Error
   message.

7. IANA Considerations value 1.

   Following the policies outlined in [IANA-CONSIDERATIONS], session
   authorization attribute types (S-Type)in
   END TIME SubType values in the range 0-127 are allocated through an
   IETF Consensus action, S-Type SubType values between 128-255 are reserved
   for Private Use and are not assigned by IANA.

   END TIME SubType NTP_TIMESTAMP is assigned the value 1.

   Following the policies outlined in [IANA-CONSIDERATIONS],
   AUTH_ENT_ID, AUTH_ENT_CRED, SESSION_ID, START_TIME, STOP_TIME,
   SOURCE_IP, DEST_IP,
   RESOURCES and DIGITAL_SIGNATURE SubType values in the range 0-127 are allocated through an
   IETF Consensus action, SubType values between 128-255 are reserved
   for Private Use and are not assigned by IANA.

8.

   RESOURCES SubType BANDWIDTH is assigned the value 1.
   SubType FLOW_SPEC is assigned the value 2.
   SubType SDP is assigned the value 3.
   SubType DSCP is assigned the value 4.

9. Security Considerations

   The purpose of this draft is to describe a mechanism for session
   authorization to prevent theft prevent theft of service.

   Replay attacks MUST be prevented. In the non-associated model, the
   AUTH_SESSION policy element MUST include a START_TIME field. The
   start time is used to verify that the request is not being replayed
   at a later time. In all other models, the SESSION_ID is used by the
   Policy Server to ensure that the resource request successfully
   correlates with records of service.

   In order to an authorized session. If a AUTH_SESSION
   is replayed, it MUST be detected by the policy server (using
   internal algorithms) and the request MUST be rejected.

   To ensure that the integrity of the token policy element is preserved in
   some
   untrusted environments, the digital signature AUTHENTICATION_DATA attribute SHOULD MUST be used.
   included.

   In fact, since order to keep the token is AUTH_SESSION policy element size to a strict
   minimum, in environments where shared private keys are possible,
   they should be relayed through the end host,
   which used. This is usually considered untrusted, we strongly recommend the
   use of especially true in wireless
   environments where the digital signature attribute.

   Simple AUTH_SESSION policy element is sent over-the-
   air. The shared private keys authentication (e.g. plain ASCII or UNICODE) does not
   contain credential that can option MUST be securely authenticated and is
   inherently less secured.

   The supported
   by all AUTH_SESSION implementations.

   If shared private keys are not a valid option, the Kerberos
   authentication mechanism is reasonably well secured.
   Kerberos secured and efficient in
   terms of AUTH_SESSION size. The AUTH_SESSION only needs to contain
   the principal@realm name of the authorizing entity. This is much
   more efficient than the PKI mechanism from
   computational point of view. authentication option.

   PKI authentication option should provide highest provides a high level of security and good
   scalability, however it requires infrastructure
   support and may have performance impacts.

9. the presence of credentials in the
   AUTH_SESSION policy element which impacts its size.

10. Acknowledgments

   We would like to thank Louis LeVay, Francois Audet, Don Wade, Hamid
   Syed, Kwok Ho Chan and many others for their valuable comments.

   In addition, we would like to thank S. Yadav, et al, for their
   efforts on RFC 3182, as this document borrows from their work.

10.

11. Normative References

   [I-REP]               S. Yadav et al, "Identity Representation for
                         RSVP", RFC 3182, October 2001

    [S-AUTH]              L-N. Hamer et al.,              Hamer, L.-N., Gage, B., Shieh, H., "Framework
                          for session setup with media authorization",
                          Internet-Draft,
                         draft-hamer-rap-session-auth-03.txt,
                         February
                          draft-ietf-rap-session-auth-04.txt,
                          June 2002.

    [ASCII]               Coded Character Set -- 7-Bit    American
                          Standard Code for Information Interchange,
                          ANSI X3.4-
                         1986.

   [IANA-CONSIDERATIONS] Alvestrand, H. and T. Narten, "Guidelines for
                         Writing an IANA Considerations Section in
                         RFCs", BCP 26, RFC 2434, October 1998.

   [POL-EXT] X3.4-1986.

    [RFC-2750]             Herzog, S., "RSVP Extensions for Policy
                          Control", RFC 2750, January 2000.

   [POL-FRAME]

    [RFC-2753]           Yavatkar, R., Pendarakis, D. and R. Guerin, "A
                          Framework for Policy-based Admission Control
                          RSVP", RFC 2753, January 2000.

    [RFC-1034]           Mockapetris, P.V., "Domain names - concepts
                         and facilities", RFC 1034, November 1987.

    [RFC-1305]            Mills, David L., "Network Time Protocol
                         (Version 3) Specification, Implementation, and
                          Analysis", RFC 1305, March 1992.

    [RFC-1321]            Rivest, R., "The MD5 Message-Digest
                          Algorithm",RFC 1321, April 1992.

    [RFC-1510]            Kohl, J. and C. Neuman, "The Kerberos Network
                          Authentication Service (V5)", RFC 1510,
                          September 1993.

   [RFC-1633]            Braden, R., Clark, D., Shenker, S.,
                         "Integrated Services in the Internet
                         Architecture: An Overview",

    [RFC-2104]            Krawczyk, H., Bellare, M. and R. Canetti,
                          "HMAC: Keyed-Hashing for Message
                          Authentication", RFC 1633,
                         June 1994. 2104, February 1997.

    [RFC-2253]            Wahl, M. et al., "UTF-8 String
                          Representation of Distinguished Names",
                          RFC 2253, December 1997.

    [RFC-2205]            Braden, R., Zhang, L., Berson, S., Herzog, S.
                          and S. Jamin, "Resource ReSerVation Protocol
                          (RSVP) - Version 1 Functional Specification",
                           RFC 2205, September 1997.

    [RFC-2209]            Braden, R. and L. Zhang, "Resource
                          ReSerVation Protocol (RSVP) - Version 1
                          Message Processing Rules", RFC 2209,
                          September 1997.

    [RFC-2327]            Handley, M., Jacobson, V., "SDP: Session
                          Description Protocol", RFC 2327, October
                          1998.

    [RFC-2396]            Berners-Lee, T., Fielding, R., Irvine, U.C.,
                          Masinter, L., "Uniform Resource Identifiers
                          (URI): Generic Syntax", RFC 2396, August
                          1998.

    [RFC-2474]            Nichols, K., Blake, S., Baker, F., Black, D.,
                          "Definition of the Differentiated Services
                         Field (DS Field) in the IPv4 and IPv6
                         Headers", RFC 2474, December 1998.

   [RFC-2998]            Bernet, Y., Ford, P., Yavatkar, R., Baker, F.,
                         Zhang, L., Speer, M., Braden, R., Davie, B.,
                         Wroclawski, J., Felstaine, E., "A Framework
                         for Integrated Services Operation over
                         Diffserv Networks", Services
                          Field (DS Field) in the IPv4 and IPv6
                          Headers", RFC 2998, November 2000. 2474, December 1998.

    [UNICODE]             The Unicode Consortium, "The Unicode Standard,
                         Version
                          Standard,Version 2.0", Addison-Wesley,
                          Reading, MA, 1996.

    [X.509]               Housley, R., Ford, W., Polk, W. and D. Solo,
                          "Internet X.509 Public Key Infrastructure
                          Certificate and CRL Profile", RFC 2459,
                          January 1999.

    [X.509-ITU]           ITU-T (formerly CCITT) Information technology -
                          Open Systems Interconnection - The Directory:
                          Authentication Framework Recommendation X.509
                          ISO/IEC 9594-8

11.

12. Informative References

   [RFC-3182]            S. Yadav et al, "Identity Representation for
                         RSVP", RFC 3182, October 2001

   [RFC-2998]            Bernet, Y., Ford, P., Yavatkar, R.,
                         Baker, F.,Zhang, L., Speer, M., Braden, R.,
                         Davie, B., Wroclawski, J., Felstaine, E., "A
                         Framework for Integrated Services Operation
                         over Diffserv Networks", RFC 2998, November
                         2000.

   [RFC-1633]            Braden, R., Clark, D., Shenker, S.,
                         "Integrated Services in the Internet
                         Architecture: An Overview", RFC 1633,
                         June 1994.

   [IANA-CONSIDERATIONS] Alvestrand, H. and T. Narten, "Guidelines for
                         Writing an IANA Considerations Section in
                         RFCs", BCP 26, RFC 2434, October 1998.

13. Author Information

      Louis-Nicolas Hamer
      Nortel Networks
      PO Box 3511 Station C
      Ottawa, Ontario
      Canada K1Y 4H7
      Phone: +1 613.768.3409
      EMail: nhamer@nortelnetworks.com

      Brett Kosinski
      University of Alberta
      Edmonton, Alberta
      Canada T6G 2M7
      EMail: kosinski@cs.ualberta.ca
      Bill Gage
      Nortel Networks
      PO Box 3511 Station C
      Ottawa, Ontario
      Canada K1Y 4H7
      Phone: +1 613.763.4400
      EMail: gageb@nortelnetworks.com

      Matt Broda
      Nortel Networks
      PO Box 3511 Station C
      Ottawa, Ontario
      Canada K1Y 4H7
      Phone: +1 613.763.7399
      EMail: mbroda@nortelnetworks.com

      Hugh Shieh
      AT&T Wireless
      7277 164th Avenue NE
      Redmond, WA
      USA 98073-9761
      Phone: +1 425.580.6898
      Email: hugh.shieh@attws.com

12.

14. Full Copyright Statement

   Copyright (C) The Internet Society (2002). All Rights Reserved. This
   document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph
   are included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organisations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into.

Expiration Date

15. Notices

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   to  pertain to the implementation or use of the technology
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   under such rights might or might not be available; neither does
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   can be found in BCP-11.  Copies of claims of rights made
   available for publication and any assurances of licenses to
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   to obtain a general license or permission for the use of such
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   specification can be obtained from the IETF Secretariat."

   "The IETF invites any interested party to bring to its
   attention any copyrights, patents or patent applications, or
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   required to practice this standard.  Please address the
   information to the IETF Executive Director."

16. RFC Editor Considerations

   This memo document references an IETF Internet-Draft that is filed in the IESG
   last call stage. Please use the corresponding RFC number prior to
   publishing of this document as <draft-ietf-rap-rsvp-authsession-02.txt>, and
   expires August 31, 2002. a RFC.  The referenced IETF I-D is
   [S-AUTH].