draft-ietf-rap-pr-04.txt   draft-ietf-rap-pr-05.txt 
Internet Draft Kwok Ho Chan A new Request for Comments is now available in online RFC libraries.
Expiration: February 2001 Nortel Networks
File: draft-ietf-rap-pr-04.txt David Durham
Intel
Silvano Gai
Cisco
Shai Herzog
IPHighway
Keith McCloghrie
Cisco
Francis Reichmeyer
PFN
John Seligson
Nortel Networks
Andrew Smith
No Affiliation
Raj Yavatkar
Intel
COPS Usage for Policy Provisioning (COPS-PR)
August 24, 2000
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
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Distribution of this memo is unlimited. Title: COPS Usage for Policy Provisioning (COPS-PR)
Author(s): K. Chan, J. Seligson, D. Durham, S. Gai,
K. McCloghrie, S. Herzog, F. Reichmeyer,
R. Yavatkar, A. Smith
Status: Standards Track
Date: March 2001
Mailbox: khchan@nortelnetworks.com, david.durham@intel.com,
sgai@cisco.com, Herzog@iphighway.com,
kzm@cisco.com, franr@pfn.com,
jseligso@nortelnetworks.com,
raj.yavatkar@intel.com, andrew@allegronetworks.com
Copyright Notice Pages: 34
Characters: 79341
Updates/Obsoletes/SeeAlso: None
Copyright (C) The Internet Society (1998). All Rights Reserved. I-D Tag: draft-ietf-rap-pr-05.txt
Abstract URL: ftp://ftp.rfc-editor.org/in-notes/rfc3084.txt
This draft describes the use of the COPS protocol [COPS] for This document describes the use of the Common Open Policy Service
support of policy provisioning (COPS-PR). This specification is (COPS) protocol for support of policy provisioning (COPS-PR). This
independent of the type of policy being provisioned (QoS, Security, specification is independent of the type of policy being provisioned
etc.) but focuses on the mechanisms and conventions used to (QoS, Security, etc.) but focuses on the mechanisms and conventions
communicate provisioned information between PDPs and PEPs. The used to communicate provisioned information between PDPs and PEPs.
protocol extensions described in this document do not make any The protocol extensions described in this document do not make any
assumptions about the policy data model being communicated, but assumptions about the policy data model being communicated, but
describe the message formats and objects that carry the modeled describe the message formats and objects that carry the modeled policy
policy data. data.
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].
Table of Contents
Abstract............................................................2
Conventions used in this document...................................2
Table of Contents...................................................3
Glossary............................................................4
1. Introduction.....................................................4
1.1. Why COPS for Provisioning?.....................................5
1.2. Interaction between the PEP and PDP............................6
2. Policy Information Base (PIB)....................................7
2.1. Rules for Modifying and Extending PIBs.........................8
2.2. Adding PRCs to, or deprecating from, a PIB.....................8
2.2.1. Adding or Deprecating Attributes of a BER Encoded PRC........8
2.3. COPS Operations Supported for a Provisioned Instance...........9
3. Message Content.................................................10
3.1. Request (REQ) PEP -> PDP.....................................10
3.2. Decision (DEC) PDP -> PEP....................................11
3.3. Report State (RPT) PEP -> PDP................................13
4. COPS-PR Protocol Objects........................................14
4.1. Complete Provisioning Instance Identifier (PRID)..............14
4.2. PRID Prefix(PPRID)............................................15
4.3. Encoded Provisioning Instance Data (EPD)......................16
4.4. Global Provisioning Error Object (GPERR)......................21
4.5. PRC Class Provisioning Error Object (CPERR)...................22
4.6. Error PRID Object (ErrorPRID).................................23
5. COPS-PR Client-Specific Data Formats............................23
5.1. Named Decision Data...........................................23
5.2. ClientSI Request Data.........................................24
5.3. Policy Provisioning Report Data...............................24
5.3.1. Success and Failure Report-Type Data Format.................24
5.3.2. Accounting Report-Type Data Format..........................25
6. Common Operation................................................26
7. Fault Tolerance.................................................28
8. Security Considerations.........................................29
9. IANA Considerations.............................................29
10. Acknowledgements...............................................29
11. References.....................................................30
12. Author Information.............................................31
13. Full Copyright Notice..........................................32
Glossary
PRC Provisioning Class. A type of policy data.
PRI Provisioning Instance. An instance of a PRC.
PIB Policy Information Base. The database of policy
information.
PDP Policy Decision Point. See [RAP].
PEP Policy Enforcement Point. See [RAP].
PRID Provisioning Instance Identifier. Uniquely identifies an
instance of a PRC.
1. Introduction
The IETF Resource Allocation Protocol (RAP) WG has defined the
COPS (Common Open Policy Service) protocol [COPS] as a scalable
protocol that allows policy servers (PDPs) to communicate policy
decisions to network devices (PEPs). COPS was designed to support
multiple types of policy clients.
COPS is a query/response protocol that supports two common models
for policy control: Outsourcing and Configuration.
The Outsourcing model addresses the kind of events at the PEP that
require an instantaneous policy decision (authorization). In the
outsourcing scenario, the PEP delegates responsibility to an
external policy server (PDP) to make decisions on its behalf. For
example, in COPS Usage for RSVP [COPRSVP] when a RSVP reservation
message arrives, the PEP must decide whether to admit or reject
the request. It can outsource this decision by sending a specific
query to its PDP, waiting for its decision before admitting the
outstanding reservation.
The COPS Configuration model (herein described as the Provisioning
model), on the other hand, makes no assumptions of such direct 1:1
correlation between PEP events and PDP decisions. The PDP may
proactively provision the PEP reacting to external events (such as
user input), PEP events, and any combination thereof (N:M
correlation). Provisioning may be performed in bulk (e.g., entire
router QoS configuration) or in portions (e.g., updating a
DiffServ marking filter).
Network resources are often provisioned based on relatively static
SLAs (Service Level Agreements) at network boundaries. While the
Outsourcing model is dynamically paced by the PEP in real-time,
the Provisioning model is paced by the PDP in somewhat flexible
timing over a wide range of configurable aspects of the PEP.
Edge Device Policy Server
+--------------+ +-----------+ +-----------+
| | | | | External |
| | COPS | | | Events |
| +-----+ | REQ() | +-----+ | +---+-------+
| | |----|----------|->| | | |
| | PEP | | | | PDP |<-|---------+
| | |<---|----------|--| | |
| +-----+ | COPS | +-----+ |
| | DEC() | |
+--------------+ +-----------+
Figure 1: COPS Provisioning Model
In COPS-PR, policy requests describe the PEP and its configurable
parameters (rather than an operational event). If a change occurs
in these basic parameters, an updated request is sent. Hence,
requests are issued quite infrequently. Decisions are not
necessarily mapped directly to requests, and are issued mostly
when the PDP responds to external events or PDP events (policy/SLA
updates).
This draft describes the use of the COPS protocol [COPS] for
support of policy provisioning. This specification is independent
of the type of policy being provisioned (QoS, Security, etc.).
Rather, it focuses on the mechanisms and conventions used to
communicate provisioned information between PDPs and PEPs. The
data model assumed in this document is based on the concept of
Policy Information Bases (PIBs) that define the policy data. There
may be one or more PIBs for given area of policy and different
areas of policy may have different sets of PIBs.
In order to support a model that includes multiple PDPs
controlling non-overlapping areas of policy on a single PEP, the
client-type specified by the PEP to the PDP is unique for the area
of policy being managed. A single client-type for a given area of
policy (eg. QoS) will be used for all PIBs that exist in that
area. The client should treat all the COPS-PR client-types it
supports as non-overlapping and independent namespaces where
instances MUST NOT be shared.
The examples used in this document are biased toward QoS Policy
Provisioning in a Differentiated Services (DiffServ) environment.
However, COPS-PR can be used for other types of provisioning
policies under the same framework.
1.1. Why COPS for Provisioning?
COPS-PR has been designed within a framework that is optimized for
efficiently provisioning policies across devices, based on the
requirements defined in [RAP]. First, COPS-PR allows for efficient
transport of attributes, large atomic transactions of data, and
efficient and flexible error reporting. Second, as it has a single
connection between the policy client and server per area of policy
control identified by a COPS Client-Type, it guarantees only one
server updates a particular policy configuration at any given
time. Such a policy configuration is effectively locked, even from
local console configuration, while the PEP is connected to a PDP
via COPS. COPS uses reliable TCP transport and, thus, uses a state
sharing/synchronization mechanism and exchanges differential
updates only. If either the server or client are rebooted (or
restarted) the other would know about it quickly. Last, it is
defined as a real-time interrupt-driven communications mechanism,
never requiring polling between the PEP and PDP.
Additionally, the COPS protocol is already used for policy control
by outsourcing signaling protocols such as RSVP. It is highly
desirable to use a single policy control protocol for Quality of
Service (QoS) mechanisms (if possible), rather than invent a new
one for each type of policy problem.
At the same time, useful mechanisms from SNMP were adopted. COPS-
PR uses a named Policy Information Base (PIB), which can be
described using the SMI [V2SMI] and encoded using BER [BER] data
encoding. This allows reuse of experience, knowledge, tools, data
models, and some code from the SNMP community. In particular, this
document describes the mechanisms used to transport data modeled
using the SMI over COPS-PR.
1.2. Interaction between the PEP and PDP
When a device boots, it opens a COPS connection to its Primary
PDP. When the connection is established, the PEP sends information
about itself to the PDP in the form of a configuration request.
This information includes client specific information (e.g.,
hardware type, software release, configuration information).
During this phase the client may also specify the maximum COPS-PR
message size supported.
In response, the PDP downloads all provisioned policies that are
currently relevant to that device. On receiving the provisioned
policies, the device maps them into its local QoS mechanisms, and
installs them. If conditions change at the PDP such that the PDP
detects that changes are required in the provisioned policies
currently in effect, then the PDP sends the changes (installs,
updates, and/or deletes) in policy to the PEP, and the PEP updates
its local configuration appropriately.
If, subsequently, the configuration of the device changes (board
removed, board added, new software installed, etc.) in ways not
covered by policies already known to the PEP, then the PEP
asynchronously sends this unsolicited new information to the PDP
in an updated configuration request. On receiving this new
information, the PDP sends to the PEP any additional provisioned
policies now needed by the PEP, or removes those policies that are
no longer required.
2. Policy Information Base (PIB)
The data carried by COPS-PR is a set of policy data. The protocol
assumes a named data structure, known as a Policy Information Base
(PIB), to identify the type and purpose of unsolicited policy
information that is "pushed" from the PDP to the PEP for
provisioning policy. The PIB name space is common to both the PEP
and the PDP and data instances within this space are unique within
the scope of a given Client-Type and Request-State per TCP
connection between a PEP and PDP. Note that given a device might
implement multiple COPS Client-Types, a unique instance space is
to be provided for each separate Client-Type. There is no sharing
of instance data across the Client-Types implemented by a PEP,
even if the types of classes being instantiated are the same.
The PIB can be described as a conceptual tree namespace where the
branches of the tree represent structures of data or Provisioning
Classes (PRCs), while the leaves represent various instantiations
of Provisioning Instances (PRIs). There may be multiple data
instances (PRIs) for any given data structure (PRC). For example,
if one wanted to install multiple access control filters, the PRC
might represent a generic access control filter type and each PRI
might represent an individual access control filter to be applied.
The tree might be represented as follows:
-------+-------+----------+---PRC--+--PRI
| | | +--PRI
| | |
| | +---PRC-----PRI
| |
| +---PRC--+--PRI
| +--PRI
| +--PRI
| +--PRI
| +--PRI
|
+---PRC---PRI
Figure 2: The PIB Tree
Instances of the policy classes (PRIs) are each identified by a
Provisioning Instance Identifier (PRID). A PRID is a name, carried
in a COPS <Named ClientSI> or <Named Decision Data> object, which
identifies a particular instance of a class.
2.1. Rules for Modifying and Extending PIBs
As experience is gained with policy management, and as new
requirements arise, it will be necessary to make changes to PIBs.
Changes to an existing PIB can be made in several ways.
(1) Additional PRCs can be added to a PIB or an existing one
deprecated.
(2) Attributes can be added to, or deprecated from, an existing
PRC.
(3) An existing PRC can be extended or augmented with a new PRC
defined in another (perhaps enterprise specific) PIB.
The rules for each of these extension mechanisms is described in
this sub-section. All of these mechanisms for modifying a PIB
allow for interoperability between PDPs and PEPs even when one
party is using a new version of the PIB while the other is using
an old version.
2.2. Adding PRCs to, or deprecating from, a PIB
A published PIB can be extended with new PRCs by simply revising
the document and adding additional PRCs. These additional PRCs
are easily identified with new PRIDs under the module's PRID
Prefix.
In the event that a PEP implementing the new PIB is being
configured by a PDP implementing the old PIB, the PEP will simply
not receive any instances of the new PRC. In the event that the
PEP is implementing the old PIB and the PDP the new one, the PEP
may receive PRIs for the new PRC. Under such conditions, the PEP
MUST return an error to the PDP, and rollback to its previous
(good) state.
Similarly, existing PRCs can be deprecated from a PIB. In this
case, the PEP ignores any PRIs sent to it by a PDP implementing
the old (non-deprecated) version of the PIB. A PDP implementing
the new version of the PIB simply does not send any instances of
the deprecated class.
2.2.1. Adding or Deprecating Attributes of a BER Encoded PRC
A PIB can be modified to deprecate existing attributes of a PRC or
add new ones.
When deprecating the attributes of a PRC, it must be remembered
that, with the COPS-PR protocol, the attributes of the PRC are
identified by their order in the sequence rather than an explicit
label (or attribute OID). Consequently, an ASN.1 value MUST be
sent even for deprecated attributes so that a PDP and PEP
implementing different versions of the PIB are inter-operable.
For a deprecated attribute, if the PDP is using a BER encoded PIB,
the PDP MUST send either an ASN.1 value of the correct type, or it
may send an ASN.1 NULL value. A PEP that receives an ASN.1 NULL
for an attribute that is not deprecated SHOULD substitute a
default value. If it has no default value to substitute it MUST
return an error to the PDP.
When adding new attributes to a PIB, these new attributes must be
added in sequence after the existing ones. A PEP that receives a
PRI with more attributes than it is expecting MUST ignore the
additional attributes and send a warning back to the PDP.
A PEP that receives a PRI with fewer attributes than it is
expecting SHOULD assume default values for the missing attributes.
It MAY send a warning back to the PDP. If the missing attributes
are required and there is no suitable default, the PEP MUST send
an error back to the PDP. In all cases the missing attributes are
assumed to correspond to the last attributes of the PRC.
2.3. COPS Operations Supported for a Provisioned Instance
A Provisioning Instance (PRI) typically contains a value for each
attribute defined for the PRC of which it is an instance and is
identified uniquely, within the scope of a given COPS Client-Type
and Request-State on a PEP, by a Provisioning Instance Identifier
(PRID). The following COPS operations are supported on a PRI:
o Install - This operation creates or updates a named instance of
a PRC. It includes two parameters: a PRID object to name the PRI
and an Encoded Provisioning Instance Data (EPD) object with the
new/updated values. The PRID value MUST uniquely identify a
single PRI (i.e. PRID prefix or PRC values are illegal). Updates
to an existing PRI are achieved by simply reinstalling the same
PRID with the updated EPD data.
o Remove - This operation is used to delete an instance of a PRC.
It includes one parameter, a PRID object, which names either the
individual PRI to be deleted or a PRID prefix naming one or more
complete classes of PRIs. Prefix-based deletion supports
efficient bulk policy removal. The removal of an unknown/non-
existent PRID SHOULD result in a warning to the PDP (no error).
3. Message Content
The COPS protocol provides for different COPS clients to define
their own "named", i.e. client-specific, information for various
messages. This section describes the messages exchanged between a
COPS server (PDP) and COPS Policy Provisioning clients (PEP) that
carry client-specific data objects. All the COPS messages used by
COPS-PR conform to the message specifications defined in the COPS
base protocol [COPS].
Note: The use of the '*' character represented throughout this
document is consistent with the ABNF [RFC2234] and means 0 or more
of the following entities.
3.1. Request (REQ) PEP -> PDP
The REQ message is sent by policy provisioning clients to issue a
'configuration request' to the PDP as specified in the COPS
Context Object. The Client Handle associated with the REQ message
originated by a provisioning client MUST be unique for that
client. The Client Handle is used to identify a specific request
state. Thus, one client can potentially open several configuration
request states, each uniquely identified by its handle. Different
request states are used to isolate similarly named configuration
information into non-overlapping contexts (or logically isolated
namespaces). Thus, an instance of named information is unique
relative to a particular client-type and is unique relative to a
particular request state for that client-type, even if the
information was similarly identified in other request states (i.e.
uses the same PRID). Thus, the Client Handle is also part of the
instance identification of the communicated configuration
information.
The configuration request message serves as a request from the PEP
to the PDP for provisioning policy data that the PDP may have for
the PEP, such as access control lists, etc. This includes policy
the PDP may have at the time the REQ is received as well as any
future policy data or updates to this data.
The configuration request message should include provisioning
client information to provide the PDP with client-specific
configuration or capability information about the PEP. The
information provided by the PEP should include client resources
(e.g. queuing capabilities) and default policy configuration (e.g.
default role combinations) information as well as incarnation data
on existing policy. This information typically does not include
all the information previously installed by a PDP but rather
should include checksums or shortened references to previously
installed information for synchronization purposes. This
information from the client assists the server in deciding what
types of policy the PEP can install and enforce. The format of the
information encapsulated in one or more of the COPS Named ClientSI
objects is described in section 5. Note that the configuration
request message is generated and sent to the PDP in response to
the receipt of a Synchronize State Request (SSQ) message from the
PDP. Likewise, an updated configuration request message (using the
same Client Handle value as the original request now being
updated) may also be generated by the PEP and sent to the PDP at
any time due to local modifications of the PEP's internal state.
In this way, the PDP will be synchronized with the PEP's relevant
internal state at all times.
The policy information supplied by the PDP MUST be consistent with
the named decision data defined for the policy provisioning
client. The PDP responds to the configuration request with a DEC
message containing any available provisioning policy data.
The REQ message has the following format:
<Request> ::= <Common Header>
<Client Handle>
<Context = config request>
*(<Named ClientSI>)
[<Integrity>]
Note that the COPS objects IN-Int, OUT-Int and LDPDecisions are
not included in a COPS-PR Request.
3.2. Decision (DEC) PDP -> PEP
The DEC message is sent from the PDP to a policy provisioning
client in response to the REQ message received from the PEP. The
Client Handle MUST be the same Handle that was received in the
corresponding REQ message.
The DEC message is sent as an immediate response to a
configuration request with the solicited message flag set in the
COPS message header. Subsequent DEC messages may also be sent at
any time after the original DEC message to supply the PEP with
additional/updated policy information without the solicited
message flag set in the COPS message header (as they are
unsolicited decisions).
Each DEC message may contain multiple decisions. This means a
single message can install some policies and delete others. In
general a single COPS-PR DEC message MUST contain any required
remove decisions first, followed by any required install
decisions. This is used to solve a precedence issue, not a timing
issue: the remove decision deletes what it specifies, except those
items that are installed in the same message.
The DEC message can also be used by the PDP to command the PEP to
open a new Request State or Delete an existing Request-State as
identified by the Client-Handle. To accomplish this, COPS-PR
defines a new flag for the COPS Decision Flags object. The flag
0x02 is to be used by COPS-PR client-types and is hereafter
referred to as the "Request-State" flag. An Install decision
(Decision Flags: Command-Code=Install) with the Request-State flag
set in the COPS Decision Flags object will cause the PEP to issue
a new Request with a new Client Handle or else specify the
appropriate error in a COPS Report message. A Remove decision
(Decision Flags: Command-Code=Remove) with the Request-State flag
set in the COPS Decision Flags object will cause the PEP to send a
COPS Delete Request State (DRQ) message for the Request-State
identified by the Client Handle in the DEC message. Whenever the
Request-State flag is set in the COPS Decision Flags object in the
DEC message, no COPS Named Decision Data object can be included in
the corresponding decision (as it serves no purpose for this
decision flag).
A COPS-PR DEC message MUST be treated as a single "transaction",
i.e. either all the decisions in a DEC message succeed or they all
fail. This allows the PDP to delete some policies only if other
policies can be installed in their place. The DEC message has the
following format:
<Decision Message> ::= <Common Header>
<Client Handle>
*(<Decision>) | <Error>
[<Integrity>]
<Decision> ::= <Context>
<Decision: Flags>
[<Named Decision Data: Provisioning >]
Note that the Named Decision Data (Provisioning) object is
included in a COPS-PR Decision when it is an Install or Remove
decision with no Decision Flags set. Other types of COPS decision
data objects (e.g. Stateless, Replacement) are not supported by
COPS-PR client-types. The Named Decision Data object MUST NOT be
included in the decision if the Decision Flags object Command-Code
is NULL (meaning there is no configuration information to install
at this time) or if the Request-State flag is set in the Decision
Flags object.
For each decision in the DEC message, the PEP performs the
operation specified in the Command-Code and Flags field in the
Decision Flags object on the Named Decision Data. For the policy
provisioning clients, the format for this data is defined in the
context of the Policy Information Base (see section 5). In
response to a DEC message, the policy provisioning client sends a
RPT message with the solicited message flag set back to the PDP to
inform the PDP of the action taken.
3.3. Report State (RPT) PEP -> PDP
The RPT message is sent from the policy provisioning clients to
the PDP to report accounting information associated with the
provisioned policy, or to notify the PDP of changes in the PEP
(Report-Type = 'Accounting') related to the provisioning client.
RPT is also used as a mechanism to inform the PDP about the action
taken at the PEP in response to a DEC message. For example, in
response to an 'Install' decision, the PEP informs the PDP if the
policy data is installed (Report-Type = 'Success') or not (Report-
Type = 'Failure'). Reports that are in response to a DEC message
MUST set the solicited message flag in their COPS message header.
In case of a solicited failure, the PEP is expected to rollback to
its previous (good) state as if the erroneous DEC transaction did
not occur.
Reports can also be unsolicited and all unsolicited Reports MUST
NOT set the solicited message flag in their COPS message header.
Examples of unsolicited reports include 'Accounting' Report-Types,
which were not triggered by a specific DEC messages, or 'Failure'
Report-Types, which indicate a failure in a previously
successfully installed configuration (note that, in the case of
such unsolicited failures, the PEP cannot rollback to a previous
"good" state as it becomes ambiguous under these asynchronous
conditions what the correct state might be).
The RPT message may contain provisioning client information such
as accounting parameters or errors/warnings related to a decision.
The data format for this information is defined in the context of
the policy information base (see section 5). The RPT message has
the following format:
<Report State> ::= <Common Header>
<Client Handle>
<Report Type>
[<Named ClientSI>]
[<Integrity>]
4. COPS-PR Protocol Objects
The COPS Policy Provisioning clients encapsulate several new
objects within the existing COPS Named Client-specific information
object and Named Decision Data object. This section defines the
format of these new objects.
COPS-PR classifies policy data according to "bindings", where a
binding consists of a Provisioning Instance Identifier and the
Provisioning Instance data, encoded within the context of the
provisioning policy information base (see section 5).
The format for these new objects is as follows:
0 1 2 3
+---------------+---------------+---------------+---------------+
| Length | S-Num | S-Type |
+---------------+---------------+---------------+---------------+
| 32 bit unsigned integer |
+---------------+---------------+---------------+---------------+
S-Num and S-Type are similar to the C-Num and C-Type used in the
base COPS objects. The difference is that S-Num and S-Type are
used only for COPS-PR clients and are encapsulated within the
existing COPS Named ClientSI or Named Decision Data objects. The
S-Num identifies the general purpose of the object, and the S-Type
describes the specific encoding used for the object. All the
object descriptions and examples in this document use the Basic
Encoding Rules as the encoding type (S-Type = 1). Additional
encodings can be defined for the remaining S-Types in the future
(for example, an additional S-Type can be used to carry XML string
based encodings [XML] as an EPD of PRI instance data, where URNs
identify PRCs [URN] and XPointers would be used for PRIDs).
Length is a two-octet value that describes the number of octets
(including the header) that compose the object. If the length in
octets does not fall on a 32-bit word boundary, padding MUST be
added to the end of the object so that it is aligned to the next
32-bit boundary before the object can be sent on the wire. On the
receiving side, a subsequent object boundary can be found by
simply rounding up the stated object length of the current object
to the next 32-bit boundary. The values for the padding MUST be
all zeros.
4.1. Complete Provisioning Instance Identifier (PRID)
S-Num = 1, S-Type = 1 (Complete BER PRID), Length = variable.
This object is used to carry the identifier, or PRID, of a
Provisioning Instance. The identifier is encoded following the
rules that have been defined for encoding SNMP Object Identifier
(OID) values. Specifically, PRID values are encoded using the
Type/Length/Value (TLV) format and initial sub-identifier packing
that is specified by the binary encoding rules [BER] used for
Object Identifiers in an SNMP PDU.
0 1 2 3
+---------------+---------------+---------------+---------------+
| Length | S-Num = PRID | S-Type = BER |
+---------------+---------------+---------------+---------------+
... ...
| Instance Identifier |
... ...
+---------------+---------------+---------------+---------------+
For example, a (fictitious) PRID equal to 1.3.6.1.2.2.8.1 would be
encoded as follows (values in hex):
06 07 2B 06 01 02 02 08 01
The entire PRID object would be encoded as follows:
00 0D - Length
01 - S-Num
01 - S-Type (Complete PRID)
06 07 2B 06 01 02 02 08 01 - Encoded PRID
00 00 00 - Padding
NOTE: When encoding an xxxTable's xxxEntry Object-Type as defined
by the SMI [V2SMI], the OID will contain all the sub-identifiers
up to and including the xxxEntry OID but not the columnar
identifiers for the attributes within the xxxEntry's SEQUENCE. The
last (suffix) identifier is the INDEX of an instance of an entire
xxxEntry including its SEQUENCE of attributes encoded in the EPD
(defined below). This constitutes an instance (PRI) of a class
(PRC) in terms of the SMI.
A PRID for a scalar (non-columnar) value's OID is encoded directly
as the PRC where the instance identifier suffix is always zero as
there will be only one instance of a scalar value. The EPD will
then be used to convey the scalar value.
4.2. PRID Prefix(PPRID)
Certain operations, such as decision removal, can be optimized by
specifying a PRID prefix with the intent that the requested
operation be applied to all PRIs matching the prefix (for example,
all instances of the same PRC). PRID prefix objects MUST only be
used in the COPS protocol <Remove Decision> operation where it may
be more optimal to perform bulk decision removal using class
prefixes instead of a sequence of individual <Remove Decision>
operations. Other COPS operations, e.g. <Install Decision>
operations always require individual PRID specification.
S-Num = 2, S-Type = 1 (BER PRID Prefix), Length = variable.
0 1 2 3
+---------------+---------------+---------------+---------------+
| Length | S-Num = PPRID | S-Type = BER |
+---------------+---------------+---------------+---------------+
... ...
| PRID Prefix |
... ...
+---------------+---------------+---------------+---------------+
Continuing with the previous example, a PRID prefix that is equal to
1.3.6.1.2.2 would be encoded as follows (values in hex):
06 05 2B 06 01 02 02
The entire PRID object would be encoded as follows:
00 0B - Length
02 - S-Num = PRID Prefix
01 - S-Type = BER
06 05 2B 06 01 02 02 - Encoded PRID Prefix
00 - Padding
4.3. Encoded Provisioning Instance Data (EPD)
S-Num = 3, S-Type = 1, Length = variable.
This object is used to carry the encoded value of a Provisioning
Instance. The PRI value, which contains all of the individual values
of the attributes that comprise the class (which corresponds to the
SMI xxxEntry Object-Type defining the SEQUENCE of attributes
comprising a table [V2SMI]), is encoded as a series of TLV sub-
components. Each sub-component represents the value of a single
attribute and is encoded following the BER. Note that the ordering
of non-scalar (multiple) attributes within the EPD is dictated by
their respective columnar OID suffix when defined in [V2SMI]. Thus,
the attribute with the smallest columnar OID suffix will appear
first and the attribute with the highest number columnar OID suffix
will be last.
0 1 2 3
+---------------+---------------+---------------+---------------+
| Length | S-Num = EPD | S-Type = BER |
+---------------+---------------+---------------+---------------+
... ...
| BER Encoded PRI Value |
... ...
+---------------+---------------+---------------+---------------+
As an example, a fictional definition of a packet filter class could
be described using the SMI as follows:
filterIpFilter OBJECT IDENTIFIER ::= { someExampleOID 1 }
-- The IP Filter Table
filterTable OBJECT-TYPE
SYNTAX SEQUENCE OF FilterEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"Filter definitions. A packet has to match all fields in
a filter. Wildcards may be specified for those fields
that are not relevant."
::= { filterIpFilter 1 }
filterEntry OBJECT-TYPE
SYNTAX FilterEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An instance of the filter class."
INDEX { filterIndex }
::= { filterTable 1 }
FilterEntry ::= SEQUENCE {
filterIndex INTEGER,
filterDstAddr IpAddress,
filterDstAddrMask IpAddress,
filterSrcAddr IpAddress,
filterSrcAddrMask IpAddress,
filterDscp Integer32,
filterProtocol INTEGER,
filterDstL4PortMin INTEGER,
filterDstL4PortMax INTEGER,
filterSrcL4PortMin INTEGER,
filterSrcL4PortMax INTEGER,
filterPermit TruthValue
}
filterIndex OBJECT-TYPE
SYNTAX INTEGER
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"An integer index to uniquely identify this filter among all
the filters."
::= { filterEntry 1 }
filterDstAddr OBJECT-TYPE
SYNTAX IpAddress
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The IP address to match against the packet's destination IP
address."
::= { filterEntry 2 }
filterDstAddrMask OBJECT-TYPE
SYNTAX IpAddress
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"A mask for the matching of the destination IP address.
A zero bit in the mask means that the corresponding bit in
the address always matches."
::= { filterEntry 3 }
filterSrcAddr OBJECT-TYPE
SYNTAX IpAddress
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The IP address to match against the packet's source IP
address."
::= { filterEntry 4 }
filterSrcAddrMask OBJECT-TYPE
SYNTAX IpAddress
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"A mask for the matching of the source IP address."
::= { filterEntry 5 }
filterDscp OBJECT-TYPE
SYNTAX INTEGER (-1 | 0..63)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The value that the DSCP in the packet can have and
match. A value of -1 indicates that a specific
DSCP value has not been defined and thus all DSCP values
are considered a match."
::= { filterEntry 6 }
filterProtocol OBJECT-TYPE
SYNTAX INTEGER (0..255)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The IP protocol to match against the packet's protocol.
A value of zero means match all."
::= { filterEntry 7 }
filterDstL4PortMin OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The minimum value that the packet's layer 4 destination
port number can have and match this filter."
::= { filterEntry 8 }
filterDstL4PortMax OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The maximum value that the packet's layer 4 destination
port number can have and match this filter."
::= { filterEntry 9 }
filterSrcL4PortMin OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The minimum value that the packet's layer 4 source port
number can have and match this filter."
::= { filterEntry 10 }
filterSrcL4PortMax OBJECT-TYPE
SYNTAX INTEGER (0..65535)
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"The maximum value that the packet's layer 4 source port
number can have and match this filter."
::= { filterEntry 11 }
filterPermit OBJECT-TYPE
SYNTAX TruthValue
MAX-ACCESS read-write
STATUS current
DESCRIPTION
"If false, the evaluation is negated. That is, a
valid match will be evaluated as not a match and vice
versa."
::= { filterEntry 12 }
A fictional instance of the filter class defined above might then
be encoded as follows:
02 01 08 :filterIndex/INTEGER/Value = 8
40 04 C0 39 01 05 :filterDstAddr/IpAddress/Value = 192.57.1.5
40 04 FF FF FF FF :filterDstMask/IpAddress/Value = 255.255.255.255
40 04 00 00 00 00 :filterSrcAddr/IpAddress/Value = 0.0.0.0
40 04 00 00 00 00 :filterSrcMask/IpAddress/Value = 0.0.0.0
02 01 FF :filterDscp/INTEGER/Value = -1 (not used)
02 01 06 :filterProtocol/INTEGER/Value = 6 (TCP)
05 00 :filterDstL4PortMin/NULL/not supported
05 00 :filterDstL4PortMax/NULL/not supported
05 00 :filterSrcL4PortMin/NULL/not supported
05 00 :filterSrcL4PortMax/NULL/not supported
02 01 01 :filterPermit/TruthValue/Value = 1 (true)
The entire EPD object for this instance would then be encoded as
follows:
00 30 - Length
03 - S-Num = EPD
01 - S-Type = BER
02 01 08 - filterIndex
40 04 C0 39 01 05 - filterDstAddr
40 04 FF FF FF FF - filterDstMask
40 04 00 00 00 00 - filterSrcAddr
40 04 00 00 00 00 - filterSrcMask
02 01 FF - filterDscp
02 01 06 - filterProtocol
05 00 - filterDstL4PortMin
05 00 - filterDstL4PortMax
05 00 - filterSrcL4PortMin
05 00 - filterSrcL4PortMax
02 01 01 - filterPermit
Note that attributes not supported within a class are still returned
in the EPD for a PRI. By convention, a NULL value is returned for
attributes that are not supported. In the previous example, source
and destination port number attributes are not supported.
4.4. Global Provisioning Error Object (GPERR)
S-Num = 4, S-Type = 1, Length = 8.
0 1 2 3
+---------------+---------------+---------------+---------------+
| Length | S-Num = GPERR | S-Type = BER |
+---------------+---------------+---------------+---------------+
| Error-Code | Error Sub-code |
+---------------+---------------+---------------+---------------+
The global provisioning error object has the same format as the
Error object in COPS [COPS], except with C-Num and C-Type replaced
by the S-Num and S-Type values shown. The global provision error
object is used to communicate general errors that do not map to a
specific PRC.
The following global error codes are defined:
availMemLow(1)
availMemExhausted(2)
unknownASN.1Tag(3) - The erroneous tag type SHOULD be
specified in the Error Sub-Code field.
maxMsgSizeExceeded(4) - COPS message (transaction) was too big.
unknownError(5)
maxRequestStatesOpen(6)- No more Request-States can be created
by the PEP (in response to a DEC
message attempting to open a new
Request-State).
invalidASN.1Length(7) - An ASN.1 object length was incorrect.
invalidObjectPad(8) - Object was not properly padded.
unknownPIBData(9) - Some of the data supplied by the PDP is
unknown/unsupported by the PEP (but
otherwise formatted correctly). PRC
specific error codes are to be used to
provide more information.
unknownCOPSPRObject(10)- Sub-code (octet 2) contains unknown
object's S-Num and (octet 3) contains
unknown object's S-Type.
malformedDecision(11) - Decision could not be parsed.
4.5. PRC Class Provisioning Error Object (CPERR)
S-Num = 5, S-Type = 1, Length = 8.
0 1 2 3
+---------------+---------------+---------------+---------------+
| Length | S-Num = CPERR | S-Type = BER |
+---------------+---------------+---------------+---------------+
| Error-Code | Error Sub-code |
+---------------+---------------+---------------+---------------+
The class-specific provisioning error object has the same format
as the Error object in COPS [COPS], except with C-Num and C-Type
replaced by the S-Num and S-Type values shown. The class-specific
error object is used to communicate errors relating to specific
PRCs and MUST have an associated Error PRID Object.
The following Generic Class-Specific errors are defined:
priSpaceExhausted(1) - no more instances may currently be
installed in the given class.
priInstanceInvalid(2) - the specified class instance is
currently invalid prohibiting
installation or removal.
attrValueInvalid(3) - the specified value for identified
attribute is illegal.
attrValueSupLimited(4) - the specified value for the identified
attribute is legal but not currently
supported by the device.
attrEnumSupLimited(5) - the specified enumeration for the
identified attribute is legal but not
currently supported by the device.
attrMaxLengthExceeded(6) - the overall length of the specified
value for the identified attribute
exceeds device limitations.
attrReferenceUnknown(7) - the class instance specified by the
policy instance identifier does not
exist.
priNotifyOnly(8) - the class is currently only supported
for use by request or report messages
prohibiting decision installation.
unknownPrc(9) - attempt to install a PRI of a class not
supported by PEP.
tooFewAttrs(10) - recvd PRI has fewer attributes than
required.
invalidAttrType(11) - recvd PRI has an attribute of the wrong
type.
deletedInRef(12) - deleted PRI is still referenced by
other (non) deleted PRIs
priSpecificError(13) - the Error Sub-code field contains the
PRC specific error code
Where appropriate (errors 3, 4, 5, 6, 7 above) the error sub-code
SHOULD identify the OID sub-identifier of the attribute
associated with the error.
4.6. Error PRID Object (ErrorPRID)
S-Num = 6, S-Type = 1 (BER ErrorPRID), Length = variable.
This object is used to carry the identifier, or PRID, of a
Provisioning Instance that caused an installation error or could
not be installed or removed. The identifier is encoded and
formatted exactly as in the PRID object as described in section
4.1.
5. COPS-PR Client-Specific Data Formats
This section describes the format of the named client specific
information for the COPS policy provisioning client. ClientSI
formats are defined for Decision message's Named Decision Data
object, the Request message's Named ClientSI object and Report
message's Named ClientSI object. The actual content of the data is
defined by the policy information base for a specific provisioning
client-type (see below).
5.1. Named Decision Data
The formats encapsulated by the Named Decision Data object for the
policy provisioning client-types depends on the type of decision.
Install and Remove are the two types of decisions that dictate the
internal format of the COPS Named Decision Data object and require
its presence. Install and Remove refer to the 'Install' and
'Remove' Command-Code, respectively, specified in the COPS
Decision Flags Object when no Decision Flags are set. The data, in
general, is composed of one or more bindings. Each binding
associates a PRID object and a EPD object. The PRID object is
always present in both install and remove decisions, the EPD
object MUST be present in the case of an install decision and MUST
NOT be present in the case of a remove decision.
The format for this data is encapsulated within the COPS Named
Decision Data object as follows:
<Named Decision Data> ::= <<Install Decision> |
<Remove Decision>>
<Install Decision> ::= *(<PRID> <EPD>)
<Remove Decision> ::= *(<PRID>|<PPRID>)
Note that PRID objects in a Remove Decision may specify PRID
prefix values. Explicit and implicit deletion of installed
policies is supported by a client. Install Decision data MUST be
explicit (i.e., PRID prefix values are illegal and MUST be
rejected by a client).
5.2. ClientSI Request Data
The provisioning client request data will use same bindings as
described above. The format for this data is encapsulated in the
COPS Named ClientSI object as follows:
<Named ClientSI: Request> ::= <*(<PRID> <EPD>)>
5.3. Policy Provisioning Report Data
The COPS Named ClientSI object is used in the RPT message in
conjunction with the accompanying COPS Report Type object to
encapsulate COPS-PR report information from the PEP to the PDP.
Report types can be 'Success' or 'Failure', indicating to the PDP
that a particular set of provisioning policies has been either
successfully or unsuccessfully installed/removed on the PEP, or
'Accounting'.
5.3.1. Success and Failure Report-Type Data Format
Report-types can be 'Success' or 'Failure' indicating to the PDP
that a particular set of provisioning policies has been either
successfully or unsuccessfully installed/removed on the PEP. The
provisioning report data consists of the bindings described above
and global and specific error/warning information.
Specific errors are associated with a particular instance. For a
'Success' Report-Type, a specific error is an indication of a
warning related to a specific policy that has been installed, but
that is not fully implemented (e.g., its parameters have been
approximated) as identified by the ErrorPRID object. For a
'Failure' Report-Type, this is an error code specific to a
binding, again, identified by the ErrorPRID object. Specific
errors may also include regular <PRID><EPD> bindings to carry
additional information in a generic manner so that the specific
errors/warnings may be more verbosely described and associated
with the erroneous ErrorPRID object.
Global errors are not tied to a specific ErrorPRID. In a 'Success'
RPT message, a global error is an indication of a general warning
at the PEP level (e.g., memory low). In a 'Failure' RPT message,
this is an indication of a general error at the PEP level (e.g.,
memory exhausted).
In the case of a 'Failure' Report-Type the PEP MUST report at
least the first error and SHOULD report as many errors as
possible. In this case the PEP MUST roll-back its configuration to
the last good transaction before the erroneous Decision message
was received.
The format for this data is encapsulated in the COPS Named
ClientSI object as follows:
<Named ClientSI: Report> ::= <[<GPERR>] *(<report>)>
<report> ::= <ErrorPRID> <CPERR> *(<PRID><EPD>)
5.3.2. Accounting Report-Type Data Format
Additionally, reports can be used to carry accounting information
when specifying the 'Accounting' Report-Type. This accounting report
message will typically carry statistical or event information
related to the installed configuration for use at the PDP. This
information is encoded as one or more <PRID><EPD> bindings that
generally describe the accounting information being reported from
the PEP to the PDP.
The format for this data is encapsulated in the COPS Named ClientSI
object as follows:
<Named ClientSI: Report> ::= <*(<PRID><EPD>)>
NOTE: RFC 2748 defines an optional Accounting-Timer (AcctTimer)
object for use in the COPS Client-Accept message. Periodic
accounting reports for COPS-PR clients are also obligated to be
paced by this timer. Periodic accounting reports SHOULD NOT be
generated by the PEP more frequently than the period specified by
the COPS AcctTimer. Thus, the period between new accounting
reports SHOULD be greater-than or equal-to the period specified
(if specified) in the AcctTimer. If no AcctTimer object is
specified by the PDP, then there are no constraints imposed on the
PEP's accounting interval.
6. Common Operation
This section describes, in general, typical exchanges between a
PDP and Policy Provisioning COPS client.
First, a TCP connection is established between the client and
server and the PEP sends a Client-Open message specifying a COPS-
PR client-type (use of the ClientSI object within the Client-Open
message is currently undefined for COPS-PR clients). If the PDP
supports the specified provisioning client-type, the PDP responds
with a Client-Accept (CAT) message. If the client-type is not
supported, a Client-Close (CC) message is returned by the PDP to
the PEP, possibly identifying an alternate server that is known to
support the policy for the provisioning client-type specified.
After receiving the CAT message, the PEP can send requests to the
server. The REQ from a policy provisioning client contains a COPS
'Configuration Request' context object and, optionally, any
relevant named client specific information from the PEP. The
information provided by the PEP should include available client
resources (e.g., supported classes/attributes) and default policy
configuration information as well as incarnation data on existing
policy. The configuration request message from a provisioning
client serves two purposes. First, it is a request to the PDP for
any provisioning configuration data which the PDP may currently
have that is suitable for the PEP, such as access control filters,
etc., given the information the PEP specified in its REQ. Also,
the configuration request effectively opens a channel that will
allow the PDP to asynchronously send policy data to the PEP, as
the PDP decides is necessary, as long as the PEP keeps its request
state open (ie. As long as the PEP does not send a DRQ with the
request state's Client Handle). This asynchronous data may be new
policy data or an update to policy data sent previously. Any
relevant changes to the PEP's internal state can be communicated
to the PDP by the PEP sending an updated REQ message. The PEP is
free to send such updated REQ messages at any time after a CAT
message to communicate changes in its local state.
After the PEP sends a REQ, if the PDP has Policy Provisioning
policy configuration information for the client, that information
is returned to the client in a DEC message containing the Policy
Provisioning client policy data within the COPS Named Decision
Data object and specifying an "Install" Command-Code in the
Decision Flags object. If no filters are defined, the DEC message
will simply specify that there are no filters using the "NULL
Decision" Command-Code in the Decision Flags object. As the PEP
MUST specify a Client Handle in the request message, the PDP MUST
process the Client Handle and copy it in the corresponding
decision message. A DEC message MUST be issued by the PDP with the
Solicited Message Flag set in the COPS message header, regardless
of whether or not the PDP has any configuration information for
the PEP at the time of the request. This is to prevent the PEP
from timing out the REQ and deleting the Client Handle.
The PDP can then add new policy data or update/delete existing
configurations by sending subsequent unsolicited DEC message(s) to
the PEP, with the same Client Handle. Previous configurations
installed on the PEP are updated by the PDP by simply re-
installing the same instance of configuration information again
(effectively overwriting the old data). The PEP is responsible for
removing the Client handle when it is no longer needed, for
example when an interface goes down, and informing the PDP that
the Client Handle is to be deleted via the COPS DRQ message.
For Policy Provisioning purposes, access state, and access
requests to the policy server can be initiated by other sources
besides the PEP. Examples of other sources include attached users
requesting network services via a web interface into a central
management application, or H.323 servers requesting resources on
behalf of a user for a video conferencing application. When such a
request is accepted, the edge device affected by the decision (the
point where the flow is to enter the network) needs to be informed
of the decision. Since the PEP in the edge device did not initiate
the request, the specifics of the request, e.g. flowspec, packet
filter, and PHB to apply, needs to be communicated to the PEP by
the PDP. This information is sent to the PEP using the Decision
message containing Policy Provisioning Named Decision Data objects
in the COPS Decision object as specified. Any updates to the state
information, for example in the case of a policy change or call
tear down, is communicated to the PEP by subsequent unsolicited
DEC messages containing the same Client Handle and the updated
Policy Provisioning request state. Updates can specify that policy
data is to be installed, deleted, or updated (re-installed).
PDPs may also command the PEP to open a new Request State or
delete an exiting one by issuing a decision with the Decision
Flags object's Request-State flag set. If the command-code is
"install", then the PDP is commanding the PEP to create a new
Request State, and therefore issue a new REQ message specifying a
new Client Handle or otherwise issue a "Failure" RPT specifying
the appropriate error condition. Each request state represents an
independent and logically non-overlapping namespace, identified by
the Client Handle, on which transactions (a.k.a. configuration
installations, deletions, updates) may be performed. Other
existing Request States will be unaffected by the new request
state as they are independent (thus, no instances of configuration
data within one Request State can be affected by DECs for another
Request State as identified by the Client Handle). If the command-
code is "Remove", then the PDP is commanding the PEP to delete the
existing Request-State specified by the DEC message's Client
Handle, thereby causing the PEP to issue a DRQ message for this
Handle.
The PEP MUST acknowledge a DEC message and specify what action was
taken by sending a RPT message with a "Success" or "Failure"
Report-Type object with the Solicited Message Flag set in the COPS
message header. This serves as an indication to the PDP that the
requestor (e.g. H.323 server) can be notified whether the request
has been accepted by the network or not. If the PEP needs to
reject the DEC operation for any reason, a RPT message is sent
with a Report-Type with the value "Failure" and optionally a
Client Specific Information object specifying the policy data that
was rejected. Under such solicited report failure conditions, the
PEP MUST always rollback to its previously installed (good) state
as if the DEC never occurred. The PDP is then free to modify its
decision and try again.
The PEP can report to the PDP the current status of any installed
request state when appropriate. This information is sent in a
Report-State (RPT) message with the "Accounting" flag set. The
request state that is being reported is identified via the
associated Client Handle in the report message.
Finally, Client-Close (CC) messages are used to cancel the
corresponding Client-Open message. The CC message informs the
other side that the client-type specified is no longer supported.
7. Fault Tolerance
When communication is lost between PEP and PDP, the PEP attempts
to re-establish the TCP connection with the PDP it was last
connected to. If that server cannot be reached, then the PEP
attempts to connect to a secondary PDP, assumed to be manually
configured (or otherwise known) at the PEP.
When a connection is finally re-established with a PDP, the PEP
sends a OPN message with a <LastPDPAddr> object providing the
address of the most recent PDP for which it is still caching
decisions. If no decisions are being cached on the PEP (due to
reboot or TTL timeout of state) the PEP MUST NOT include the last
PDP address information. Based on this object, the PDP may request
the PEP to re-synch its current state information (by issuing a
COPS SSQ message). If, after re-connecting, the PDP does not
request synchronization, the client can assume the server
recognizes it and the current state at the PEP is correct, so a
REQ message need not be sent. Still, any state changes which
occurred at the PEP that the PEP could not communicate to the PDP
due to communication having been lost, MUST be reported to the PDP
via the PEP sending an updated REQ message. Whenever re-
synchronization is requested, the PEP MUST reissue any REQ
messages for all known Request-States and the PDP MUST issue DEC
messages to delete either individual PRIDs or prefixes as
appropriate to ensure a consistent known state at the PEP.
While the PEP is disconnected from the PDP, the active request-
state at the PEP is to be used for policy decisions. If the PEP
cannot re-connect in some pre-specified period of time, all
installed Request-States are to be deleted and their associated
Handles removed. The same holds true for the PDP; upon detecting a
failed TCP connection, the time-out timer is started for all
Request-States associated with the PEP and these states are
removed after the administratively specified period without a
connection.
8. Security Considerations
The use of COPS for Policy Provisioning introduces no new security
issues over the base COPS protocol [COPS]. The security mechanisms
described in that document will also be deployed in a COPS-PR
environment.
9. IANA Considerations
COPS for Policy Provisioning follows the same IANA considerations
for COPS objects as the base COPS protocol [COPS]. COPS-PR does,
however, introduce a new object number space in its S-Num and S-
Type. Additional S-Num and S-Types can only be added using the
IETF Consensus rule as defined in [IANA] (note that the S-Type
value of 2 is reserved for transport of XML encoded data).
Likewise, additional Global Provisioning error codes for COPS-PR
can only be added with IETF Consensus.
10. Acknowledgements
This document has been developed with active involvement from a
number of sources. The authors would specifically like to
acknowledge the valuable input given by Michael Fine, Scott Hahn,
and Carol Bell.
11. References
[COPS] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja, R.,
Sastry, A., "The COPS (Common Open Policy Service)
Protocol", IETF RFC 2748, Proposed Standard, January 2000.
[RAP] Yavatkar, R., et al., "A Framework for Policy Based
Admission Control", IETF RFC 2753, January 2000.
[COPRSVP] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja, R.,
Sastry, A., "COPS usage for RSVP", IETF RFC 2749, Proposed
Standard, January 2000.
[ASN1] Information processing systems - Open Systems
Interconnection, "Specification of Abstract Syntax Notation
One (ASN.1)", International Organization for
Standardization, International Standard 8824, December
1987.
[BER] Information processing systems - Open Systems
Interconnection - Specification of Basic Encoding Rules for
Abstract Syntax Notation One (ASN.1), International
Organization for Standardization. International Standard
8825, (December, 1987).
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
Weiss, W., "An Architecture for Differentiated Service,"
RFC 2475, December 1998.
[V2SMI] McCloghrie, K., Perkins, D., Schoenwaelder, J., Case, J.,
Rose, M. and S. Waldbusser, "Structure of Management
Information Version 2(SMIv2)", STD 58, RFC 2578, April
1999.
[RFC2234] Crocker, D., Overell, P., " Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
[IANA] Alvestrand, H. and Narten, T., "Guidelines for writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[URN] Moats, R., "Uniform Resource Names (URN) Syntax", RFC 2141,
May 1997.
[XML] World Wide Web Consortium (W3C), "Extensible Markup
Language (XML)," W3C Recommendation, February, 1998,
http://www.w3.org/TR/1998/REC-xml-19980210.
12. Author Information
Shai Herzog IPHighway Inc.
Phone: (201) 585-0800 Parker Plaza, 16th Floor
Email: Herzog@iphighway.com 400 Kelby St.
Fort-Lee, NJ 07024
Francis Reichmeyer PFN, Inc.
(617) 494 9980 University Park at MIT
franr@pfn.com 26 Landsdowne Street
Cambridge, MA 02139
Kwok Ho Chan Nortel Networks, Inc.
Phone: (978) 288-8175 600 Technology Park Drive
EMail: khchan@nortelnetworks.com Billerica, MA 01821
David Durham Intel
Phone: (503) 264-6232 2111 NE 25th Avenue
Email: david.durham@intel.com Hillsboro, OR 97124
Raj Yavatkar
Phone: (503) 264-9077
Email: raj.yavatkar@intel.com
Silvano Gai Cisco Systems, Inc.
Phone: (408) 527-2690 170 Tasman Dr.
Email: sgai@cisco.com San Jose, CA 95134-1706
Keith McCloghrie This document is a product of the Resource Allocation Protocol Working
Phone: (408) 526-5260 Group of IETF.
Email: kzm@cisco.com
Andrew Smith This is now a Proposed Standard Protocol.
415 345 1827 fax
ah_smith@pacbell.net
John Seligson Nortel Networks, Inc. This document specifies an Internet standards track protocol for
Phone: (408) 495-2992 4401 Great America Parkway the Internet community, and requests discussion and suggestions
Email:jseligso@nortelnetworks.com Santa Clara, CA 95054 for improvements. Please refer to the current edition of the
"Internet Official Protocol Standards" (STD 1) for the
standardization state and status of this protocol. Distribution
of this memo is unlimited.
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 End of changes. 

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