Internet Draft                                            Shai Herzog
Expiration: July August 1999                                       IPHighway
File: draft-ietf-rap-rsvp-ext-02.txt draft-ietf-rap-rsvp-ext-03.txt

                  RSVP Extensions for Policy Control

                          January 22,

                           February 13, 1999

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Abstract

   This memo presents a set of extensions for supporting generic policy
   based admission control in RSVP. It should be perceived as an
   extension to the RSVP functional specifications [RSVP]

   These extensions include the standard format of POLICY_DATA objects,
   and a description of RSVP's handling of policy events.

   This document does not advocate particular policy control
   mechanisms;
   however, a Router/Server Policy Protocol description for these
   extensions can be found in [RAP, COPS, COPS-RSVP].

Table of Contents

Abstract...............................................................1

Abstract.............................................................1
Table of Contents......................................................2
1. Introduction........................................................3
2. Contents....................................................2
1 Introduction.......................................................3
2 Policy Data Object Format...........................................3
2.1. Format..........................................3
2.1  Base Format.......................................................4
2.2. Options...........................................................4
2.2.1.Native Format.....................................................4
2.2  Options.........................................................4
2.3  Native RSVP Options..............................................5
2.2.2.Other Options....................................................6
2.3. Options.............................................5
2.3.1 Other Options..................................................6
2.4  Policy Elements...................................................7
3. Elements.................................................7
3 Processing Rules....................................................7
3.1. Rules...................................................7
3.1  Basic Signaling...................................................7
3.2. Signaling.................................................7
3.2  Default Handling..................................................7
3.3. Handling................................................7
3.3  Error Signaling...................................................8
4. Signaling.................................................8
4 IANA Considerations.................................................8
5. References..........................................................9
6. Acknowledgments.....................................................9
7. Considerations................................................9
5 References.........................................................9
6 Acknowledgments....................................................9
7 Author Information..................................................9 Information.................................................9
A. Appendix: Policy Error Codes.......................................10

1. Codes......................................10

1  Introduction

  RSVP, by definition, discriminates between users, by providing some
  users with better service at the expense of others. Therefore, it is
  reasonable to expect that RSVP be accompanied by mechanisms for
  controlling and enforcing access and usage policies.  Historically,
  when RSVP Ver. 1 was developed, the knowledge and understanding of
  policy issues was in its infancy. As a result, Ver. 1 of the RSVP
  Functional Specifications [RSVP] left a place holder for policy
  support in the form of POLICY_DATA objects. However, it deliberately
  refrained from specifying mechanisms, message formats, or providing
  insight into how policy enforcement should be carried out. This
  document is intended to fill in this void.

  The current RSVP Functional Specification describes the interface to
  admission (traffic) control that is based "only" on resource
  availability. In this document we describe a set of extensions to
  RSVP for supporting policy based admission control as well. The
  scope of this document is limited to these extensions and does not
  advocate specific architectures for policy based controls.

  For the purpose of this document we do not differentiate between
  Policy Decision Point (PDP) and Local Decision Point (LDPs) as
  described in [RAP]. The term PDP should be assumed to include LDP as
  well.

2.

2  Policy Data Object Format

  The following replaces section A.13 in [RSVP].

  POLICY_DATA objects are carried by RSVP messages and contain policy
  information. All policy-capable nodes (at any location in the
  network) can generate, modify, or remove policy objects, even when
  senders or receivers do not provide, and may not even be aware of
  policy data objects.

  The exchange of POLICY_DATA objects between policy-capable nodes
  along the data path, supports the generation of consistent end-to-end end-to-
  end policies. Furthermore, such policies can be successfully
  deployed across multiple administrative domains when border nodes
  manipulate and translate POLICY_DATA objects according to
  established sets of bilateral agreements.

2.1.

2.1 Base Format

  POLICY_DATA class=14

  o   Type 1 POLICY_DATA object: Class=14, C-Type=1

      +-------------+-------------+-------------+-------------+
      |  Length                   | POLICY_DATA |      1      |
      +---------------------------+-------------+-------------+
      |  Data Offset              | 0 (reserved)              |
      +---------------------------+-------------+-------------+
      |                                                       |
      // Option List                                         //
      |                                                       |
      +-------------------------------------------------------+
      |                                                       |
      // Policy Element List                                 //
      |                                                       |
      +-------------------------------------------------------+

      Data Offset: 16 bits

          The offset in bytes of the data portion (from the first
          byte of the object header).

      Reserved: 16 bits

           Always 0.

      Option List: Variable length

          The list of options and their usage is defined in Section
          2.2.

      Policy Element List: Variable length

          The contents of policy elements is opaque to RSVP. See more
          details in Section 2.3.

2.2. 2.4.

2.2 Options

  This section describes a set of options that may appear in
  POLICY_DATA objects. All policy options appear as RSVP objects; some
  use their valid original format while others appear as NULL objects.

2.2.1.

2.3 Native RSVP Options

  The following objects retain the same format specified in [RSVP]
  however, they gain different semantics when used inside POLICY_DATA
  objects.

  FILTER_SPEC object (list) or SCOPE object

  The set of senders associated with the POLICY_DATA object. If none
  is provided, the policy information is assumed to be associated with
  all the flows of the session. These two types of objects are
  mutually exclusive, and cannot be mixed.

  This option is only useful for WF or SE reservation styles, where
  merged reservations may have originally been intended for different
  subsets of senders. It can also be used to prevent “policy loops” in
  a manner similar to the usage of RSVP’s SCOPE object. Using this
  option may have significant impact on scaling and size of
  POLICY_DATA objects and therefore should be taken with care.

  Originating RSVP_HOP

  The RSVP_HOP object identifies the neighbor/peer policy-capable node
  that constructed the policy object. When policy is enforced at
  border nodes, peer policy nodes may be several RSVP hops away from
  each other and the originating RSVP_HOP is the basis for the
  mechanism that allows them to recognize each other and communicate
  safely and directly.

  If no RSVP_HOP object is present, the policy data is implicitly
  assumed to have been constructed by the RSVP_HOP indicated in the
  RSVP message itself (i.e., the neighboring RSVP node is policy-capable). policy-
  capable).

  Destination RSVP_HOP

  A second RSVP_HOP object may follow the originating RSVP_HOP object.
  This second RSVP_HOP identifies the destination policy node. This is
  used to ensure the POLICY_DATA object is delivered to targeted
  policy nodes. It may be used to emulate unicast delivery in
  multicast Path messages. It may also help prevent using a policy
  object in other parts of the network (replay attack).

  On the receiving side, a policy node should ignore any POLCY_DATA
  that includes a destination RSVP_HOP that doesn’t match its own IP
  address.

  INTEGRITY Object
  The INTEGRITY object provides guarantees that the object was not
  compromised. It follows the rules from [MD5], and is calculated over
  the POLICY_DATA object, the SESSION object, and the message type
  field (byte, padded with zero to 32 bit) as if they formed one
  continuous in-
  order in-order message.  This concatenation is designed to
  prevent copy and replay attacks of POLICY_DATA objects from other
  sessions, flows, message types or even other network locations.

2.2.2.

2.3.1  Other Options

  All options that do not use a valid RSVP object format, should use
  the NULL RSVP object format with different CType C-Type values. This
  document defines only one such option, however, several other may be
  considered in future versions.  (e.g., Fragmentation, NoChange,
  etc.).

  o    Policy Refresh Period (PRP)

  The Policy Refresh Period (PRP) option is used slow down policy
  refresh frequency for policies that have looser timing constraints
  compared with RSVP. If the PRP option is present, policy refreshes
  can be withheld as long as at least one refresh is sent before the
  policy refresh timer expires (PRP must be bigger than R).

  +-------------+-------------+-------------+-------------+
  |             8             |    NULL     |     1       |
  +-------------+-------------+-------------+-------------+
  |         Policy Refresh Period (PRP) (in seconds)      |
  +-------------+-------------+---------------------------+

  It is recommended that this infrequent policy refresh would be
  piggybacked with normal RSVP refreshes. Given an RSVP refresh R, the
  policy must be refreshed at least once in N RSVP refreshes, where
  N=Floor(PRP/R) and the Floor function provides the integer portion
  of the result.

  In effect, state cleanup rules apply specifically to the POLICY_DATA
  object as if the RSVP refresh period was N*R.

  Any RSVP update must include the full policy information. For
  example, a policy being refreshed at time T, T+N, T+2N,... may
  encounter a route change detected at T+X such that T < T+X < T+N.
  The update event would force an immediate update of the policy and
  change its refresh times to T+X, T+X+N, T+X+2N,...

  When network nodes restart, it is possible that an RSVP message in
  between policy refreshes would be rejected since it arrives to a
  node that did not receive the original POLICY_DATA object.  This
  error situation would clear with the next periodic policy refresh or
  by an update triggered by ResvErr or PathErr messages.

  This option is especially useful to combine strong (high overhead)
  and weak (low overhead) authentication certificates. In such schemes
  the weak certificate supports admitting a reservation only for a
  limited time, after which the strong certificate is required.

  This approach may reduce the overhead of POLICY_DATA processing.
  Strong certificates could be transmitted less frequently, while weak
  certificates could be included in every RSVP refresh.

2.3.

2.4 Policy Elements

  The content of policy elements is opaque to RSVP; their internal
  format is understood by policy peers e.g. an RSVP Local Decision
  Point (LDP) or a Policy Decision Point (PDP) [RAP]. A registry of
  policy element codepoints and their meaning is maintained by [IANA-CONSIDERATIONS] [IANA-
  CONSIDERATIONS] (also see Section 4).

  Policy Elements have the following format:

  +-------------+-------------+-------------+-------------+
  |  Length                   |   P-Type                  |
  +---------------------------+---------------------------+
  |                                                       |
  // Policy information  (Opaque to RSVP)                //
  |                                                       |
  +-------------------------------------------------------+

3.

3  Processing Rules

  These sections describe the minimal required policy processing rules
  for RSVP.

3.1.

3.1 Basic Signaling

  It is generally agreed that policy control should only be enforced
  for Path, Resv, PathErr, and ResvErr. PathTear and ResvTear and
  assumed not to require policy control based on two assumptions:
  First, that Integrity verification [MD5] guarantee that the Tear is
  received from the same node that sent the installed reservation, and
  second, that it is functionally equivalent to that node holding-off
  refreshes for this reservation.

3.2.

3.2 Default Handling

  It is generally assumed that policy enforcement (at least in its
  initial stages) is likely to concentrate on border nodes between
  autonomous systems. Consequently, policy objects transmitted at one
  edge of an autonomous cloud may traverse intermediate policy
  ignorant RSVP nodes (PINs). A PIN is required at a minimum to
  forward the received POLICY_DATA objects in the appropriate outgoing
  messages according to the following rules:

  o    POLICY_DATA objects are to be forwarded as is, without any
       modifications.

  o    Multicast merging (splitting) nodes:

       In the upstream direction:

          When multiple POLICY_DATA objects arrive from downstream, the
          RSVP node should concatenate all of them and forward them
          with the outgoing (upstream) message.

       On the downstream direction:

          When a single incoming POLICY_DATA object arrives from
          upstream, it should be forwarded (copied) to all downstream
          branches of the multicast tree.

  The same rules apply to unrecognized policies (sub-objects) within
  the POLICY_DATA object. However, since this can only occur in a policy-
  capable
  policy-capable node, it is the responsibility of the PDP and not
  RSVP.

3.3.

3.3 Error Signaling

  Policy errors are reported by either ResvErr or PathErr messages
  with a policy failure error code in the ERROR_SPEC object. Policy
  error message must include a POLICY_DATA object; the object contains
  details of the error type and reason in a P-Type specific format.

  If a multicast reservation fails due to policy reasons, RSVP should
  not attempt to discover which reservation caused the failure (as it
  would do for Blockade State). Instead, it should attempt to deliver
  the policy ResvErr to ALL downstream hops, and have the PDP (or LDP)
  decide where messages should be sent. This mechanism allows the PDP
  to limit the error distribution by deciding which "culprit" next-hops next-
  hops should be informed. It also allows the PDP to prevent further
  distribution of ResvErr or PathErr messages by performing local
  repair (e.g. substituting the failed POLICY_DATA object with a
  different one).

  Error codes are described in Appendix A.

4.

4  IANA Considerations

  RSVP Policy Elements

  Following the policies outlined in [IANA-CONSIDERATIONS],numbers 0-
  49151 are allocated as standard policy elements by IETF Consensus
  action, numbers in the range 49152-53247 are allocated as vendor
  specific (one per vendor) by First Come First Serve, and numbers 53248-
  65535
  53248-65535 are reserved for private use and are not assigned by
  IANA.

5.

5  References

  [RAP]  Yavatkar, R., et al., "A Framework for Policy Based Admission
         Control",IETF <draft-ietf-rap-framework-02.txt>, Jan., 1999.

  [COPS] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja,n R.,
         Sastry, A., "The COPS (Common Open Policy Service) Protocol",
         IETF <draft-ietf-rap-cops-05.txt>, Jan. 1999.

  [RSVP] Braden, R. ed., "Resource ReSerVation Protocol (RSVP) -
         Functional Specification.", IETF RFC 2205, Proposed Standard,
         Sep. 1997.

  [MD5]  Baker, F., Linden B., Talwar, M. “RSVP Cryptographic
         Authentication" Internet-Draft, <draft-ietf-rsvp-md5-07.txt>,
         Nov. 1998.

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

6.

6  Acknowledgments

  This document incorporates inputs from Lou Berger, Bob Braden,
  Deborah Estrin, Roch Guerin, Timothy O'Malley, Dimitrios Pendarakis,
  Raju Rajan, Scott Shenker, Andrew Smith, Raj Yavatkar, and many
  others.

7.

7  Author Information

  Shai Herzog, IPHighway
  Parker Plaza, Suite 1500
  400 Kelby St.
  Fort-Lee, NJ 07024
  (201) 585-0800
  herzog@iphighway.com

A. Appendix: Policy Error Codes

  This Appendix expends the list of error codes described in Appendix
  B of [RSVP].

  Note that Policy Element specific errors are reported as described
  in Section 3.3 and cannot be reported through RSVP (using this
  mechanism). However, this mechanism provides a simple, less secure
  mechanism for reporting generic policy errors. Most likely the two
  would be used in concert such that a generic error code is provided
  by RSVP, while Policy Element specific errors are encapsulated in a
  return POLICY_DATA object (as in Section 3.3).

  ERROR_SPEC class = 6

  Error Code = 02: Policy Control failure

  Error Value: 16 bit

  0 = ERR_INFO    : Information reporting
  1 = ERR_WARN    : Warning
  2 = ERR_UNKNOWN : Reason unknown
  3 = ERR_REJECT  : Generic Policy Rejection
  4 = ERR_EXCEED  : Quota or Accounting violation
  5 = ERR_PREEMPT : Flow was preempted
  6 = ERR_EXPIRED : Previously installed policy expired (not
  refreshed)
  7 = ERR_REPLACED: Previous policy data was replaced & caused
  rejection
  8 = ERR_MERGE   : Policies could not be merged (multicast)
  9 = ERR_PDP     : PDP down or non functioning
  10= ERR_SERVER  : Third Party Server (e.g., Kerberos) unavailable
  11= ERR_PD_SYNTX: POLICY_DATA object has bad syntax
  12= ERR_PD_INTGR: POLICY_DATA object failed Integrity Check
  13= ERR_PE_BAD  : POLICY_ELEMENT object has bad syntax
  14= ERR_PD_MISS : Mandatory PE Missing (Empty PE is in the PD
  object)
  15= ERR_NO_RSC  : PEP Out of resources to handle policies.
  16= ERR_RSVP    : PDP encountered bad RSVP objects or syntax
  17= ERR_SERVICE : Service type was rejected
  18= ERR_STYLE   : Reservation Style was rejected
  19= ERR_FL_SPEC : FlowSpec was rejected (too large)

  Values between 2^15 and 2^16-1 can be used for site and/or vendor
  error values.