WDIFF

draft-ietf-rap-rsvp-ext-04.txt --> draft-ietf-rap-rsvp-ext-05.txt

Internet Draft Shai Herzog
Expiration: August October 1999 IPHighway
File: draft-ietf-rap-rsvp-ext-04.txt draft-ietf-rap-rsvp-ext-05.txt
Updates RFC 2205

RSVP Extensions for Policy Control

February 26,

April 2, 1999

Status of this Memo

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

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.

Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other documents
at any time. It is inappropriate to use Internet-Drafts as
reference material or to cite them other than as "work in progress."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt

The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

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].

Internet Draft Expires August October 1999 [Page 1]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99 2-Apr-99

Table of Contents

Abstract.............................................................1
Table of Contents....................................................2
1 Introduction.......................................................3
2 Policy Data Object Format..........................................3 Objects................................................3
2.1 Base Format.....................................................4
2.2 Options.........................................................4
2.3 Native RSVP Options.............................................5 Policy Elements.................................................6
2.4 Other Options...................................................6
2.5 Purging Policy Elements.................................................7 State............................................7
3 Processing Rules...................................................7
3.1 Basic Signaling.................................................7
3.2 Default Handling................................................7
3.3 Error Signaling.................................................8
4 IANA Considerations................................................9
5 Security Considerations............................................9
6 References........................................................10
7 Acknowledgments...................................................10
8 Author Information................................................10
A. Appendix:
Appendix A: Policy Error Codes.....................................11 Codes......................................11

Shai Herzog Expires August October 1999 [Page 2]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99 2-Apr-99

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 placeholder 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. object.

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 Policy Data Object Format

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

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 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.

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

Shai Herzog Expires August October 1999 [Page 3]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99 2-Apr-99

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 2.5. 2.3.

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.

Shai Herzog Expires August 1999 [Page 4]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99

2.3 Native RSVP Options

The following objects retain the same format specified in [RSVP]
however, they gain different semantics but
their semantic is modified when used inside POLICY_DATA
objects. as policy data options.

FILTER_SPEC object (list) or SCOPE object

The

These objects describe 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

Shai Herzog Expires October 1999 [Page 4]

Internet Draft RSVP Extensions for Policy Control 2-Apr-99

In Packed FF Resv messages, this FILTER_SPEC option provides
association between a reserved flow and its POLICY_DATA objects.

In WF or SE reservation styles, where
merged reservations this option preserves the original
flow/POLICY_DATA association as formed by PDPs, even across RSVP
capable PIN nodes. Such preservation is required since PIN nodes may have originally been intended for different
subsets
change the list of senders. It can also reserved flows on a per-hop basis, irrespective
of legitimate Edge-to-Edge PDP policy considerations.

Last, the SCOPE object should be used to prevent "policy loops" in a
manner similar to the usage one described in [RSVP], Section 3.4. When PIN
nodes are part of RSVP's a WF reservation path, the RSVP SCOPE object is
unable to prevent policy loops and the separate policy SCOPE object
is required.

Note: using the SCOPE object. Using this option may have significant impact on scaling
and size of POLICY_DATA objects and therefore should be taken with care. objects.

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).

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 POLICY_DATA
that includes a destination RSVP_HOP that doesn't match its own IP
address.

INTEGRITY Object

Shai Herzog Expires August 1999 [Page 5]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99

The INTEGRITY object provides guarantees that the object was not
compromised. It follows the rules from [MD5], and is calculated over

Shai Herzog Expires October 1999 [Page 5]

Internet Draft RSVP Extensions for Policy Control 2-Apr-99

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 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.

2.4 Other Options

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

Policy Refresh Period (PRP) TIME_VALUES (PRT)

The Policy Refresh Period (PRP) TIME_VALUES (PRT) option is used to slow down policy
refresh frequency for policies that have looser timing constraints
compared with
relative to RSVP. If the PRP PRT 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 expires. A minimal value for PRT is recommended that this infrequent policy refresh would R; lower
values are assumed to be
piggybacked with normal RSVP refreshes. Given an R (neither error nor warning should be
triggered).

To simplify RSVP refresh R, processing, time values are not based directly on
the
policy must be refreshed at least once in PRT value, but on a Policy Refresh Multiplier N RSVP refreshes, where
N=Floor(PRP/R) computed as
N=Floor(PRT/R). Refresh 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 are derived from [RSVP]
Section 3.7 assuming the RSVP refresh period was N*R.

Any RSVP update must include for PRT POLICY DATA is R'
computed as R'=N*R. In effect, both the full policy information. refresh and the state
cleanup are slowed by a factor of N).

The refresh multiplier applies to no-change periodic refreshes only
(rather than updates). 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 T+X. In
this case, the event would force an immediate update of the policy update and
change its
would reset refresh times to T+X, T+X+N, T+X+2N,...

When network nodes restart, it is possible that an RSVP message in messages between PRT policy
refreshes would may be rejected since it arrives to a
node that did not receive the original they arrive without necessary
POLICY_DATA object. objects. This error situation would clear with the next
periodic policy refresh or
by an with a policy update triggered by ResvErr
or PathErr messages.

Shai Herzog Expires August 1999 [Page 6]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99

This option is especially useful to combine strong (high overhead)
and weak (low overhead) authentication certificates. certificates as policy data.
In such schemes the weak certificate supports can support 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 are included in every RSVP refresh.

2.5

2.3 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

Shai Herzog Expires October 1999 [Page 6]

Internet Draft RSVP Extensions for Policy Control 2-Apr-99

policy element codepoints and their meaning is maintained by [IANA-
CONSIDERATIONS] (also see Section 4).

Policy Elements have the following format:

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

2.4 Purging Policy State

Policy state expires in the granularity of Policy Elements
(POLICY_DATA objects are mere containers and do not expire as such).

Policy elements expire in the exact manner and time as the RSVP
state received in the same message (see [RSVP] Section 3.7). PRT
controlled state expires N times slower (see Section 2.2).

Only one policy element of a certain P-Type can be active at any
given time. Therefore, policy elements are instantaneously replaced
when another policy element of the same P-Type is received from the
same PDP (previous or next policy RSVP_HOP). An empty policy element
of a certain P-Type is used to delete (rather than a replace) all
policy state of the same P-Type.

3 Processing Rules

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

3.1 Basic Signaling

It is generally agreed that

This draft mandates enforcing policy control should only be enforced for Path, Resv,
PathErr, and ResvErr. ResvErr messages only. PathTear and ResvTear and are
assumed not to require policy control based on two assumptions: main
presumptions. 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 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

Shai Herzog Expires October 1999 [Page 7]

Internet Draft RSVP Extensions for Policy Control 2-Apr-99

forward the received POLICY_DATA objects in the appropriate outgoing
messages according to the following rules:

Shai Herzog Expires August 1999 [Page 7]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99

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 (as a list of the
original POLICY_DATA objects) 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 node, it is the responsibility of the PDP and not
RSVP.

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. format
(See Section 2.3).

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 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.

Shai Herzog Expires August October 1999 [Page 8]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99 2-Apr-99

4 IANA Considerations

RSVP Policy Elements (P-Types)

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 are reserved for private use and are not assigned by
IANA.

5 Security Considerations

This draft describes the use of POLICY_DATA objects to carry policy-
related information between RSVP nodes. Two security mechanisms can
be optionally used to ensure the integrity of the carried
information. The first mechanism relies on RSVP integrity [MD5] to
provide a chain of trust when all RSVP nodes are policy capable. The
second mechanism relies on the INTEGRITY object within the
POLICY_DATA object to guarantee integrity between non-neighboring
RSVP PEPs. (See PEPs (see Section 2.3). 2.2).

Shai Herzog Expires August October 1999 [Page 9]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99 2-Apr-99

6 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.

[COPS-RSVP] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja,n R.,
Sastry, A., "COPS Usage for RSVP", IETF <draft-ietf-rap-cops-
rsvp-04.txt>, Feb. 1999.

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

[MD5] Baker, F., Linden Lindell 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.

7 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.

8 Author Information

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

Shai Herzog Expires August October 1999 [Page 10]

Internet Draft RSVP Extensions for Policy Control 26-Feb-99

A. Appendix: 2-Apr-99

Appendix A: Policy Error Codes

This Appendix expends extends 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.

Shai Herzog Expires August October 1999 [Page 11]

----