One document matched: draft-lefaucheur-tsvwg-rsvp-multiple-preemption-00.txt




TSVWG                                                     F. Le Faucheur
Internet-Draft                                                  A. Kudur
Intended status: Standards Track                            A. Narayanan
Expires: January 4, 2010                                           Cisco
                                                            July 3, 2009


          Multiple Preemption Priority Policy Element for RSVP
         draft-lefaucheur-tsvwg-rsvp-multiple-preemption-00.txt

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Abstract

   RSVP Extensions are being defined allowing an endpoint to signal
   alternate "bandwidths" of interest in case the preferred bandwidth is
   not available and allowing the RSVP routers to collectively establish
   the reservation with the highest currently achievable bandwidth among
   the signaled set.  This can be used to achieve efficient dynamic
   endpoint codec adjustment.  The present document presents a
   complementary set of extensions, allowing the dynamic bandwidth
   selection to reflect a different reservation priority for each of the
   multiple "bandwidth" associated with a reservation.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Conventions Used in This Document  . . . . . . . . . . . .  4
   2.  Overview of RSVP Extensions and Operations . . . . . . . . . .  5
     2.1.  Policy Example 1 . . . . . . . . . . . . . . . . . . . . .  6
     2.2.  Policy Example 2 . . . . . . . . . . . . . . . . . . . . .  7
   3.  Multiple Preemption Priority Policy Element Format . . . . . .  9
   4.  Processing Rules . . . . . . . . . . . . . . . . . . . . . . . 11
     4.1.  Default Handling . . . . . . . . . . . . . . . . . . . . . 11
     4.2.  Associating Priorities With TSPECs and FLOWSPECs . . . . . 11
     4.3.  Merging Rules  . . . . . . . . . . . . . . . . . . . . . . 12
   5.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
     5.1.  Use of RSVP Authentication between RSVP neighbors  . . . . 13
     5.2.  Use of INTEGRITY object within the POLICY_DATA object  . . 13
   6.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 15
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 16
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 17
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 17
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19

















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1.  Introduction

   Guaranteed QoS for some applications with tight QoS requirements may
   be achieved by reserving resources in each node on the end-to-end
   path.  The Resource ReSerVation Protocol (RSVP) ([RFC2205]) is a
   protocol specified by the IETF supporting such on-path QoS signaling
   and resource reservation.

   Today, real-time applications and endpoints have evolved such that
   they are very often capable of transmitting at different bandwidth
   rates.  This is achieved by various techniques including the use of
   layered coding (and transmission of only a subset of these layers) or
   by reducing frame rates, resolution or quality at a given resolution.
   Endpoints also often have the ability to adjust their transmission
   rate dynamically mid-session with little or no artifact.

   Typically, a higher bandwidth allows to achieve higher quality of
   experience so that it is desirable to take advantage of higher
   bandwidth when available.  However, when only lower bandwidth is
   available, it is desirable that the endpoints adjust their
   transmission rate accordingly, to avoid generating excess traffic
   that is likely to create congestion that will affect even the base
   quality layer of that session as well as the quality of other
   sessions sharing the same network resources.  Thus, network resource
   reservation mechanisms such as RSVP ( [RFC2205]) can provide a lot of
   value to real time applications by facilitating dynamic encoding/
   bandwidth adjustment.

   It is possible to use RSVP and Intserv in their present form to
   achieve dynamic encoding/bandwidth adjustment through an iterative
   trial-and-error approach: i.e. attempt to reserve bandwidth for the
   highest quality; if that fails, attempt to reserve bandwidth for the
   next quality level down, and so on.  However, extensions to RSVP/
   Intserv are required to support a more efficient approach that allows
   determination and reservation, within a single signaling round-trip,
   of the highest currently achievable quality level.
   [I-D.polk-tsvwg-intserv-multiple-tspec] proposes a first set of
   extensions to IntServ to that effect.  To put it simply, these
   extensions allow:

   o  a sender to signal the multiple "bandwidth" (or more precisely,
      multiple sender traffic specifications) at which it can transmit

   o  a receiver to convey multiple "bandwidth" (or more precisely,
      multiple flow specifications) in a preference order when making
      the reservation request





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   o  RSVP routers to collectively establish the reservation with the
      highest currently achievable "bandwidth" among the ones signaled
      by the receiver.

   This document presents a complementary set of extensions, allowing
   the dynamic bandwidth selection to reflect a different reservation
   priority for each of the multiple "bandwidth" associated with a
   reservation.

   With these two complementary set of extensions, it is possible to
   enforce sophisticated cross-session policies during dynamic
   bandwidth/codec adjustment.  For example, the network operator can
   ensure that the "base" encoding layer of any session be given higher
   priority than "enhancement layers" of any session.  This may be
   desirable if the policy is to maximize the number of sessions that
   can be supported (with their minimum quality/resolution guaranteed).
   As another example, the network operator can ensure that the "base
   layer" and "mid layer" of a premium session are given high priority,
   while base layer of normal sessions are given medium priority, while
   every else is given low priority.  This may be desirable if the
   policy is to ensure that granting good resolution to premium sessions
   is favored over accepting more regular sessions, but establishing
   more regular sessions is favored over granting highest resolution to
   premium sessions.

1.1.  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 [RFC2119].





















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2.  Overview of RSVP Extensions and Operations

   [RFC2750] presents a set of extensions for supporting generic policy
   based admission control in RSVP.  These extensions include the
   standard format of POLICY_DATA objects, and a description of RSVP's
   handling of policy events.  These extensions are consistent with the
   framework for policy-based admission control presented in [RFC2753].
   POLICY_DATA objects are carried by RSVP messages and contain policy
   information.  The exchange of POLICY_DATA objects between policy-
   capable nodes along the data path, supports the generation and
   enforcement of consistent end-to-end admission control policies.

   POLICY_DATA objects contain a list of Policy Elements that each
   contain a single unit of information necessary for the evaluation of
   policy rules.  Multiple policy elements are already specified.  For
   example, [RFC2872] specifies the Application and Sub Application
   Identity policy element for use with RSVP.

   [RFC3181] specifies another policy element, the Preemption Priority
   Policy Element, that can be signaled in RSVP so that network node may
   take into account this policy element in order to preempt some
   previously admitted low priority sessions in order to make room for a
   newer, higher priority session.  The Preemption Priority Policy
   Element contains:

   o  one Preemption Priority specifying the priority of the new flow
      compared with the defending priority of previously admitted flows.

   o  one Defending Priority that is used once this reservation is
      established to compare with the preemption priority of new flows.

   The present document specifies a new Policy Element called the
   Multiple Preemption Priority Policy Element.  The Multiple Preemption
   Priority Policy Element complements (and does not replace) the
   existing Preemption Priority Policy Element, so that a separate set
   of preemption priority and defending priority can be associated to
   each traffic specification or flow specification that may be signaled
   as per [I-D.polk-tsvwg-intserv-multiple-tspec].

   For example, imagine that (using the extensions defined in
   [I-D.polk-tsvwg-intserv-multiple-tspec]) a receiver R1 signals three
   flow specifications (corresponding to the three encoding rates
   supported by the corresponding sender).  And let us refer to those as
   Flowspec1 (say with rate r=12 Mb/s), Flowspec2 (say with r=4 Mb/s)
   and Flowspec3 (say with r=1.5 Mb/s).  In accordance with
   [I-D.polk-tsvwg-intserv-multiple-tspec], FlowSpec1 will be carried in
   the FLOWSPEC object, while Flowspec2 and FlowSpec3 will be carried in
   the MULTI-FLOWSPEC object.



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   With the extensions defined in the present document, the receiver can
   also:

   o  associate a pair of preemption priority and defending priority to
      the first FlowSpec (Flowspec1) using the existing Preemption
      Priority Policy Element (as per existing procedures)

   o  associate a different pair of preemption priority and defending
      priority to any other FlowSpec (Flowspec2 and Flowspec3) using the
      new Multiple Preemption Priority Policy Element (as per teh new
      procedures defined in the present document).

   Then, whenever an RSVP router performs admission control, it can
   enforce the preemption and defending priorities of each flow spec and
   therefore enforce sophisticated policies for dynamic bandwidth
   adjustment.  Example of policies and how they can be achieved using
   the present extensions are described in Section 2.1 and Section 2.2.

2.1.  Policy Example 1

   Assume an environment where all codecs support 3 levels of
   resolution/quality: base, medium, enhanced.

   Assume that the operator policy is characterized by the following
   rules:

   o  all sessions are of equal importance

   o  a reservation for a base layer is allowed to preempt a reservation
      for medium/enhanced layer if needed to be established

   o  a reservation for a medium layer is allowed to preempt a
      reservation for enhanced layer if needed to be established.

   Then the operator policy can be supported by signaling the following
   preemption priorities:















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                         +----------+
                         | All      |
                         | Sessions |
   +---------+-----------+----------+
   | Quality | Flowspec  | Prior(*) |
   +---------+-----------+----------+
   +---------+-----------+----------+
   | Base    | Flowspec1 | High     |
   +---------+----------+-----------+
   | Medium  | Flowspec2 | Mid      |
   +---------+-----------+----------+
   | Enhanced| Flowspec3 | Low      |
   +---------+-----------+----------+

   (*) Preemption Priority = Defending Priority

    Figure 1: Multiple Preemption Priority Values for Policy Example 1

2.2.  Policy Example 2

   Assume an environment where all codecs support 3 levels of
   resolution/quality: base, medium, enhanced.

   Assume that the operator policy is characterized by the following
   rules:

   o  there are two levels of importance for sessions: Premium and
      Normal

   o  a reservation for base/medium layer of Premium is allowed to
      preempt a reservation for enhanced layer of Premium and for medium
      and enhanced or Normal sessions, if needed to be established

   o  a reservation for a base layer of Normal is allowed to preempt a
      reservation for medium and enhanced layer of Normal, if needed to
      be established.

   o  a reservation for a medium layer of Normal is allowed to preempt a
      reservation for enhanced layer of Normal, if needed to be
      established.

   Then the operator policy can be supported by signaling the following
   preemption priorities:








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                         +----------+----------+
                         | Normal   | Premium  |
                         | Sessions | Sessions |
   +---------+-----------+----------+----------+
   | Quality | Flowspec  | Prior(*) | Prior(*) |
   +---------+-----------+----------+----------+
   +---------+-----------+----------+----------+
   | Base    | Flowspec1 | High     | High     |
   +---------+----------+-----------+----------+
   | Medium  | Flowspec2 | Mid      | High     |
   +---------+-----------+----------+----------+
   | Enhanced| Flowspec3 | Low      | Low      |
   +---------+-----------+----------+----------+

   (*) Preemption Priority = Defending Priority

    Figure 2: Multiple Preemption Priority Values for Policy Example 2


































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3.  Multiple Preemption Priority Policy Element Format

   [RFC2750] defines extensions for supporting generic policy based
   admission control in RSVP.  These extensions include the standard
   format of POLICY_DATA objects and a description of RSVP handling of
   policy events.

   The POLICY_DATA object contains one or more of Policy Elements, each
   representing a different (and perhaps orthogonal) policy.  As an
   example, [RFC3181] specifies the Preemption Priority Policy Element.
   This document defines one new Policy Elements called the Multiple
   Preemption Priority Policy Element.  The Multiple Preemption Priority
   Policy Element contains a series of Priority Sub-Elements; each Sub-
   Element contains a preemption priority and a defending priority.  The
   format of the Multiple Preemption Priority policy element is as shown
   in Figure 3.The format of the Priority Sub-Element is as shown in
   Figure 4.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     | Length                        | P-Type = MULTI_PREEMPTION_PRI |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Priority Sub-Element 1                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
               ...                             ...
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Priority Sub-Element N                  |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


           Figure 3: Multiple Preemption Priority Policy Element

   o  Length: 16 bits

      *  The overall length of the policy element, in bytes.

   o  P-Type: 16 bits

      *  MULTI_PREEMPTION_PRI = To be allocated by IANA (see "IANA
         Considerations" section)










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      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Preemption Priority       |       Defending Priority      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 4: Priority Sub-Element

   Preemption Priority N: 16 bits (unsigned)

   o  Preemption Priority of the Sub-Element.  Encoding is same as
      corresponding field in [RFC3181] Preemption Priority Policy
      Element.

   Defending Priority N: 16 bits (unsigned)

   o  Defending Priority of the Sub-Element.  Encoding is same as
      corresponding field in [RFC3181] Preemption Priority Policy
      Element.
































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4.  Processing Rules

4.1.  Default Handling

   As specified in section 4.2 of [RFC2750], Policy Ignorant Nodes
   (PINs) implement a default handling of POLICY_DATA objects ensuring
   that those objects can traverse PIN nodes in transit from one PEP to
   another.  This applies to the situations where POLICY_DATA objects
   contain the Multiple Preemption Priority Policy Element specified in
   this document, so that those can traverse PIN nodes.

   Section 4.2 of [RFC2750] also defines a similar default behavior for
   policy-capable nodes that do not recognized a particular Policy
   Element.  This applies to the Multiple Preemption Priority Policy
   Element specified in this document, so that those can traverse
   policy-capable nodes that do not support the extensions defined in
   the present document.

4.2.  Associating Priorities With TSPECs and FLOWSPECs

   This section defines how the multiple priority sub-elements conveyed
   in the Preemption Priority Policy Element and the Multiple Preemption
   Priority Policy Element are to be associated with the multiple
   traffic specification (respectively flow specifications) of a Path
   (respectively Resv) message.

   Each POLICY object can contain at most a single Multiple Preemption
   Priority Policy Element.  If no Preemption Priority Policy Element is
   present in the same POLICY_DATA object then the Multiple Preemption
   Priority Policy Element MUST be ignored.

   The preemption priority and defending priority of the Preemption
   Priority Policy Element carried in a Resv message MUST be associated
   with the flow specification carried in the FLOWSPEC object.  The
   preemption priority and defending priority in each sub-element of the
   Multiple Preemption Priority Policy Element MUST be associated with
   the flow specification carried in the corresponding position in the
   MULTI_FLOWSPEC object.  If a Resv message contains no MULTI_FLOWSPEC
   object, but contains a Multiple Preemption Priority Policy Element in
   the POLICY_DATA object, then the Multiple Preemption Priority Policy
   Element MUST be ignored.  If there are more sub-elements in the
   Multiple Preemption Priority Policy Element than there are flow
   specifications in the MULTI_FLOWSPEC object, then the extra sub-
   elements MUST be ignored.  If there are fewer priorities in the
   Multiple Preemption Priority Policy Element than there are flow
   specifications in the MULTI_FLOWSPEC object, then the extra flow
   specifications SHOULD be associated with preempt and defend
   priorities of 0 (the lowest priorities).  This MAY be overridden by



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   local policy.  This rule also applies for a Resv message containing a
   MULTI_FLOWSPEC but no Multiple Preemption Priority Policy Element;
   all the flow specifications in the MULTI_FLOWSPEC SHOULD be
   associated with default preempt and defend priorities of 0.  It is
   important to note that this document places no restriction on the
   relative priorities of different flow specifications.  Indeed, it is
   possible for smaller flow specifications in a MULTI_FLOWSPEC to have
   a lower priority than larger flow specifications.

   For Multiple Preemption Priority Policy Elements carried in PATH
   messages, the same rules apply relating to the MULTI_SENDER_TSPEC
   object as they do to the MULTI_FLOWSPEC object described above.

   With some reservation styles (e.g.  Fixed Filter), the Resv message
   may contain more than one flow descriptor (and therefore more than
   one FLOWSPEC and MULTI_FLOWSPEC objects).  As specified in section
   3.2 of [RFC2750], the POLICY_DATA object can be associated with all
   flows of the session or associated with an explicit set of senders
   (e.g. by including a FILTER_SPEC object in the Options List preceding
   the Policy Element List).  This existing mechanisms are not modified
   and may be used to explicitly associate a Multiple Preemption
   Priority Policy Element with an explicit set of senders (and in turn
   with the corresponding FLOWSPEC and MULTI_FLOWSPEC).  The Preemption
   Priority and Multiple Preemption Priority Policy Elements contained
   in a POLICY_DATA object with no fields in the Options list MUST apply
   to all senders and/or receivers in the message, except for those
   which have been specifically overridden by policy elements in
   additional POLICY_DATA objects with their FILTER_SPEC in the Options
   list.

4.3.  Merging Rules

   As mentioned above, each element of a MULTI_FLOWSPEC is associated
   with a single preempt and defend priority element from a Multiple
   Preemption Priority Policy Element.  When merging multiple
   reservations, the two component FLOWSPECs are merged into a single
   FLOWSPEC, and the two component MULTI_FLOWSPECs are merged into a
   single MULTI_FLOWSPEC.The merged FLOWSPEC object is composed as per
   [RFC2205], by computing the envelope of all flow specification
   components.  The merged MULTI_FLOWSPEC is composed by taking all the
   flow specification components from the individual MULTI_FLOWSPEC
   objects, in descending order of bandwidth.  If the component Resv
   messages contain POLICY_DATA objects with Multiple Preemption
   Priority policy elements, the merged reservation MUST contain a
   Multiple Preemption Priority policy element.  This element is
   composed by combining each of the individual preempt and defend
   priority sub-elements associated with each of the flow specification
   components in the merged MULTI_FLOWSPEC, in the same order.



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5.  Security Considerations

   As this document defines extensions to RSVP, the security
   considerations of RSVP apply.  Those are discussed in [RFC2205],
   [RFC4230] and [I-D.ietf-tsvwg-rsvp-security-groupkeying].  Approaches
   for addressing those concerns are discussed further below.

   A subset of RSVP messages are signaled with the Router Alert Option
   (RAO)([RFC2113],[RFC2711]).  The security aspects and common
   practices around the use of the current IP Router Alert option and
   consequences on the use of IP Router Alert by applications such as
   RSVP are discussed in [I-D.rahman-rtg-router-alert-considerations].

   The Multiple Preemption Priority Policy Element defined in this
   document are signaled by RSVP through encapsulation in a Policy Data
   object as defined in [RFC2750].  Therefore, like any other Policy
   Elements, its integrity can be protected as discussed in section 6 of
   [RFC2750] by two optional security mechanisms.  The first mechanism
   relies on RSVP Authentication as specified in [RFC2747] and [RFC3097]
   to provide a chain of trust when all RSVP nodes are policy capable.
   With this mechanism, the INTEGRITY object is carried inside RSVP
   messages.  The second mechanism relies on the INTEGRITY object within
   the POLICY_DATA object to guarantee integrity between RSVP Policy
   Enforcement Points (PEPs) that are not RSVP neighbors.

5.1.  Use of RSVP Authentication between RSVP neighbors

   RSVP authentication can be used between RSVP neighbors that are
   policy capable.  RSVP Authentication (defined in [RFC2747] and
   [RFC3097]) SHOULD be supported by an implementation of the present
   document.

   With RSVP authentication, the RSVP neighbors use shared keys to
   compute the cryptographic signature of the RSVP message.
   [I-D.ietf-tsvwg-rsvp-security-groupkeying] discusses key types, key
   provisioning methods as well as their respective applicability.

5.2.  Use of INTEGRITY object within the POLICY_DATA object

   The INTEGRITY object within the POLICY_DATA object can be used to
   guarantee integrity between non-neighboring RSVP PEPs.  This is
   useful only when some RSVP nodes are Policy Ignorant Nodes (PINs).
   The INTEGRITY object within the POLICY_DATA object MAY be supported
   by an implementation of the present document.

   Details for computation of the content of the INTEGRITY object can be
   found in Appendix B of [RFC2750].  This states that the Policy
   Decision Point (PDP), at its discretion, and based on destination



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   PEP/PDP or other criteria, selects an Authentication Key and the hash
   algorithm to be used.  Keys to be used between PDPs can be
   distributed manually or via standard key management protocol for
   secure key distribution.

   Note that where non-RSVP hops may exist in between RSVP hops, as well
   as where RSVP capable Policy Ignorant Nodes (PINs) may exist in
   between PEPs, it may be difficult for the PDP to determine what is
   the destination PDP for a POLICY_DATA object contained in some RSVP
   messages (such as a Path message).  This is because in those cases
   the next PEP is not known at the time of forwarding the message.  In
   this situation, key shared across multiple PDPs may be used.  This is
   conceptually similar to the use of key shared across multiple RSVP
   neighbors discussed in [I-D.ietf-tsvwg-rsvp-security-groupkeying].
   We observe also that this issue may not exist in some deployment
   scenarios where a single (or low number of) PDP is used to control
   all the PEPs of a region (such as an administrative domain).  In such
   scenarios, it may be easy for a PDP to determine what is the next hop
   PDP, even when the next hop PEP is not known, simply by determining
   what is the next region that will be traversed (say based on the
   destination address).






























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6.  IANA Considerations

   As specified in [RFC2750], Standard RSVP Policy Elements (P-type
   values) are to be assigned by IANA as per "IETF Consensus" policy
   following the policies outlined in [RFC2434] (this policy is now
   called "IETF Review" as per [RFC5226]) .

   IANA needs to allocate one P-Type from the Standard RSVP Policy
   Element range to the Multiple Preemption Priority Policy Element.










































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7.  Acknowledgments

   This document benefited from discussions with Subha Dhesikan and
   James Polk.















































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8.  References

8.1.  Normative References

   [I-D.polk-tsvwg-intserv-multiple-tspec]
              Polk, J. and S. Dhesikan, "Integrated Services (IntServ)
              Extension to Allow Multiple TSPECs",
              draft-polk-tsvwg-intserv-multiple-tspec-00 (work in
              progress), March 2009.

   [RFC2113]  Katz, D., "IP Router Alert Option", RFC 2113,
              February 1997.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2205]  Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
              Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
              Functional Specification", RFC 2205, September 1997.

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 2434,
              October 1998.

   [RFC2711]  Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
              RFC 2711, October 1999.

   [RFC2747]  Baker, F., Lindell, B., and M. Talwar, "RSVP Cryptographic
              Authentication", RFC 2747, January 2000.

   [RFC2750]  Herzog, S., "RSVP Extensions for Policy Control",
              RFC 2750, January 2000.

   [RFC3097]  Braden, R. and L. Zhang, "RSVP Cryptographic
              Authentication -- Updated Message Type Value", RFC 3097,
              April 2001.

   [RFC3181]  Herzog, S., "Signaled Preemption Priority Policy Element",
              RFC 3181, October 2001.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.

8.2.  Informative References

   [I-D.ietf-tsvwg-rsvp-security-groupkeying]
              Behringer, M. and F. Faucheur, "Applicability of Keying



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              Methods for RSVP Security",
              draft-ietf-tsvwg-rsvp-security-groupkeying-05 (work in
              progress), June 2009.

   [I-D.rahman-rtg-router-alert-considerations]
              Faucheur, F., "IP Router Alert Considerations and Usage",
              draft-rahman-rtg-router-alert-considerations-01 (work in
              progress), March 2009.

   [RFC2753]  Yavatkar, R., Pendarakis, D., and R. Guerin, "A Framework
              for Policy-based Admission Control", RFC 2753,
              January 2000.

   [RFC2872]  Bernet, Y. and R. Pabbati, "Application and Sub
              Application Identity Policy Element for Use with RSVP",
              RFC 2872, June 2000.

   [RFC4230]  Tschofenig, H. and R. Graveman, "RSVP Security
              Properties", RFC 4230, December 2005.
































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Authors' Addresses

   Francois Le Faucheur
   Priority Cisco Systems
   Greenside, 400 Avenue de Roumanille
   Sophia Antipolis  06410
   France

   Phone: +33 4 97 23 26 19
   Email: flefauch@cisco.com


   Arun Kudur
   Cisco Systems
   SEZ Unit, Cessna Business Park, Kadubeesanahalli Village
   Bangalore, Karnataka  560 103
   India

   Email: akudur@cisco.com


   Ashok Narayanan
   Cisco Systems
   1414 Massachusetts Avenue
   Boxborough  01719
   USA

   Email: ashokn@cisco.com























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PAFTECH AB 2003-20262026-04-23 04:24:24