Internet Draft                                    Kwok Ho Chan
Expiration: September 2000 January 2001                             Nortel Networks
File: draft-ietf-rap-pr-02.txt draft-ietf-rap-pr-03.txt                    David Durham
                                                  Silvano Gai
                                                  Shai Herzog
                                                  Keith McCloghrie
                                                  Francis Reichmeyer
                                                  John Seligson
                                                     Nortel Networks
                                                  Andrew Smith
                                                     Extreme Networks
                                                     No Affiliation
                                                  Raj Yavatkar

                  COPS Usage for Policy Provisioning

                            March 10,

                            July 14, 2000

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
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Copyright Notice

  Copyright (C) The Internet Society (1998).  All Rights Reserved.


  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.) but
  focuses on the mechanisms and conventions used to communicate
  provisioned information between PDPs and PEPs. The protocol
  extensions described in this document do not make any assumptions
  about the policy data being communicated, but describe the message
  formats and objects that carry policy data.

Table of Contents


Table of Contents.....................................................4
Glossary..............................................................5 Contents.....................................................3
1. Introduction.....................................................5 Introduction.....................................................4
1.1. Why not SNMP?..................................................6 SNMP?..................................................5
1.2. Interaction between the PEP and PDP............................7 PDP............................6
2. Policy Information Base (PIB)....................................8 (PIB)....................................7
2.1. Rules for Modifying and Extending PIBs.........................9 PIBs.........................8
2.2. Adding PRCs to, or deprecating from, a PIB.....................9 PIB.....................8
2.2.1. Adding or Deprecating Attributes of a PRC......................9
2.2.2. Augmenting a PRC with another PRC.............................10 BER Encoded PRC..........8
2.3. COPS Operations Supported for a Policy Rule Instance..........10 Instance...........9
3. Message Content.................................................11 Content.................................................10
3.1. Request (REQ)  PEP -> PDP.....................................11 PDP.....................................10
3.2. Decision (DEC)  PDP -> PEP....................................12 PEP....................................11
3.3. Report State (RPT)  PEP -> PDP................................14 PDP................................13
4. COPS-PR Protocol Objects........................................14 Objects........................................13
4.1. Complete Policy Rule Identifier (PRID)........................15 (PRID)........................14
4.2. Prefix PRID (PPRID)...........................................16 Prefix(PPRID)............................................15
4.3. Encoded Policy Instance Data (EPD)............................16
4.4. Global Provisioning Error Object (PERR)..............................18 (GPERR)......................17
4.5. PRC Class Provisioning Error Object (CPERR)...................18
4.6. Error PRID Object (ErrorPRID).................................19
5. COPS-PR Client-Specific Data Formats............................19
5.1. Named Decision Data...........................................20
5.2. ClientSI Request Data.........................................20
5.3. Policy Provisioning Report Data...............................20
5.3.1. Success and Failure Report-Type Data Format...................21
5.3.2. Accounting Report-Type Data Format............................21
6. Common Operations...............................................22 Operation................................................22
7. Fault Tolerance.................................................24
7.1. Security Considerations.......................................25
8. Acknowledgements................................................25
9. References......................................................26
10. Author Information..............................................27
11. Full Copyright Notice...........................................28


   PRC     Policy Rule Class.  A type of policy data.
   PRI     Policy Rule Instance.  An instance of a PRC.
   PIB     Policy Information Base.  The database of policy
   PDP     Policy Decision Point. See [RAP-FRAMEWORK].
   PEP     Policy Enforcement Point. See [RAP-FRAMEWORK].
   PRID    Policy Rule 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 (PEP). (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 instantaneous policy decision (authorization). The PEP,
   being aware that it must perform a policy decision. However, being
   unable to carry In the task itself,
   outsourcing scenario, the PEP delegates responsibility to an
   external policy server (PDP). (PDP) to make decision on its behalf. For
   example, in [COPS-RSVP] when a RSVP reservation message arrives,
   the PEP is aware that it must decide whether to admit or reject the request. It sends can
   outsource this decision by sending a specific query to the its PDP, and in most case, waits
   waiting for a its decision before admitting the outstanding

   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

   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.) but,
   rather, focuses on the mechanisms and conventions used to
   communicate provisioned information between PDPs and PEPs. The
   model described 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 will 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
   client-type specified by the PEP to the PDP is unique for the area
   of policy being managed. A single client type 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 not SNMP?
   SNMP is a very popular network management protocol. One may
   question using COPS-PR, rather than extending SNMP for policy

   SNMP is designed for low-level access at very fine levels of
   granularity.  When configuring large amounts of policy
   information, the low-level, granular access makes it inefficient
   and cumbersome.

   COPS-PR has been designed within a framework which is less
   general-purpose and more optimized for configuration to overcome
   these shortcomings, based on the requirements defined in [RAP]. It
   has a single connection between client and server, it guarantees
   only one server updates the policy configuration at any given time
   (and these are locked, even from console configuration, while COPS
   is connected to a server). 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 mechanism for the PEP device.

   The COPS protocol is already used for policy control over 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 and
   some code from the SNMP world.

  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 (installs,
   updates, and/or deletes) in policy to the PEP, and the PEP updates
   its local QoS mechanisms 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.
   On receiving this new information, the PDP sends to the PEP any
   additional provisioned policies now needed by the PEP.

2. Policy Information Base (PIB)

   The data carried by COPS-PR is a set of policy rules. The protocol
   uses 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 PDP/PEP/Client-Type communication channel. Client-Type and Request-State per TCP
   connection between a PEP and PDP. Note that a given a device might
   implement multiple PEPs or multiple
   Client-Types and the name space COPS Client-Types, a unique namespace is then only relevant within to be
   provided for each separate channel Client-Type (there is no sharing of
   instance data across the
   PDP/PEP/Client-Types). 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 data structure namespace where the
   branches of the tree represent types of rules or Policy Rule
   Classes (PRCs), while the leaves represent the contents various instantiations
   of Policy Rule Instances (PRIs). There may be multiple instances
   of rules (PRIs) for any given rule type (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:

                    |       |          |        +--PRI
                    |       |          |
                    |       |          +---PRC-----PRI
                    |       |
                    |       +---PRC--+--PRI
                    |                +--PRI
                    |                +--PRI
                    |                +--PRI
                    |                +--PRI

                          Figure 2: The PIB Tree

   Instances of the policy rules (PRIs) are each identified by a
   Policy Rule 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 rule.

  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

    (2) Attributes can be added to, or deprecated from an existing

    (3) An existing PRC can be extended by "augmenting" it 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

   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.  The Under such conditions, the PEP SHOULD ignore these
   unsupported PRI.  However, it MAY
   MUST return and an error to the PDP.  In
   the latter case, the PDP must restructure its policy decisions PDP, and rollback to
   exclude the unsupported PRCs. its previous
   (good) state.

   Similarly, existing PRCs can be deprecated from a PIB.  In this
   case, the PEP ignores any PRIs sent 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.  It MAY 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
   and 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 Policy Rule Instance

   A Policy Rule 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 Policy Rule 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 Policy Instance Data (EPD) object with the
     new/updated values. The PRID value MUST uniquely identify a
     single PRI (i.e. PRID/PRC prefix 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.

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, a piece 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. states (i.e. uses the same
   PRID). Thus, the Client Handle is also part of the instance
   identification of the communicated configuration information.

   The config configuration request message serves as a request from the PEP
   to the PDP for provisioning policy data which 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 config 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 resource resources
   (e.g. queuing capabilities) and default policy configuration (e.g.
   default role combinations) information as well as references to
   existing policy (i.e. PIB) incarnation data. 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 the
   provisioning Named ClientSI data is described in section 5. Note
   that the config configuration request message is regenerated generated and sent to
   the PDP in response to the receipt of a Synchronize State Request
   (SSQ) message. message from the PDP. Likewise, an updated configuration
   request message 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 config 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: Provisioning >]

   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 COPS-PR decision message should contain at most one or
   more deletes followed by one or more install decisions. This is
   used to solve a precedence issue, not a timing issue: the delete
   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 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 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(s)>) | <Error>

   <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 on 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.
   Reports can also be unsolicited and all unsolicited Reports MUST
   NOT set
   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,
   that were not triggered by a specific DEC messages, or 'Failure'
   Report-Types that indicate a change of state failure in a previously successfully
   installed configuration. configuration (Note that in the case of such unsolicited
   failures, the PEP cannot rollback to a previous "good" state as
   such becomes ambiguous under such asynchronous conditions).

   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: Provisioning >]

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 Policy Rule Identifier and the Policy Rule
   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, XML string based encodings).

   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.

  4.1. Complete Policy Rule 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 Policy
   Rule 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  |
   ...                                                           ...
   |                     Policy Rule Identifier                    |
   ...                                                           ...

   For example, a (fictitious) PRID equal to 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. 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 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 Policy Instance Data (EPD)

   S-Num = 3, S-Type = 1, Length = variable.

   This object is used to carry the encoded value of a Policy Rule
   Instance. The PRI value, which contains all of the individual
   values of the attributes that comprise the class, 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.
           0                1               2                 3
   |             Length            | S-Num = EPD   | S-Type = BER  |
   ...                                                           ...
   |                     BER Encoded PRI Value                     |
   ...                                                           ...

   As an example, an instance of the filter class, defined in the QoS
   Policy IP
   Framework PIB [PIB], would be encoded as follows:

   02 01 08            :filterIndex/INTEGER/Value = 8
   40 04 C0 39 01 05   :filterDstAddr/IpAddress/Value =
   40 04 FF FF FF FF   :filterDstMask/IpAddress/Value =
   40 04 00 00 00 00   :filterSrcAddr/IpAddress/Value =
   40 04 00 00 00 00   :filterSrcMask/IpAddress/Value =
   02 01 FF            :filterDscp/Integer32/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 would 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

  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:


             Note: For the unknownASN.1Tag, the

     unknownASN.1Tag(3)     - The erroneous tag type MUST be
                              specified in the Error Sub-Code field field.
     maxMsgSizeExceeded(4)  - COPS message (transaction) was too big.
     maxRequestStatesOpen(6)- No more Request-States can be created
                              by the PEP (in response to a DEC
                              message attempting to open a new
     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 PEP (but
                              otherwise formatted correctly). PRC
                              specific error codes are to be used to
                              provide more information.

  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:

     unknownPrc(9), -- install a PRI of a

     priSpaceExhausted(1) -     no more instances may currently be
                                installed in the given class.

     priInstanceInvalid(2) -    the specified class instance is
                                currently invalid prohibiting
     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 PEP
     noAccess(10), -- 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
     priNotifyOnly(8) -         the class is currently implemented as a
                                'notify' prohibiting decision
     unknownPrc(9) -            attempt to install a PRI of a class whose access is notify
     tooFewAttrs(11), -- not
                                supported by PEP.
     tooFewAttrs(10) -          recvd PRI has fewer attributes than
     invalidAttrType(12), --
     invalidAttrType(11) -      recvd PRI has an attribute of the wrong
     deletedInRef(13), --
     deletedInRef(12)  -        deleted PRI is still referenced by
                                other (non) deleted PRIs

     Note: For the priSpecificError code
     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 Policy
   Rule 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
   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:

     < Decision: Named 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:

   <ClientSI: Named 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

  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 policy rule. 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:

   <ClientSI: Named 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 PDP.

   The format for this data is encapsulated in the COPS Named ClientSI
   object as follows:

   <ClientSI: Named 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 COPS Named ClientSI
   object as follows:

   <ClientSI: Named Report> ::= <*(<PRID><EPD>)> AcctTimer.

6. Common Operations 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, Policy Provisioning client. 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, 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 references to existing policy
   (i.e., PIB) incarnation data. 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 to its local

   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
   state 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
   the 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) must 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, must 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 deleted installed, deleted, or installed. 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 an
   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 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

   The PEP acknowledges the a DEC message and action 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 that the request has been accepted by the
   network. If the PEP needs to reject the DEC operation for any
   reason, a RPT message is sent with a Report-Type of value
   "Failure" and optionally a Client Specific Information object
   specifying the policy data that was rejected. Under such failure
   conditions, the PEP MUST always rollback to its previously
   installed (good) state as if the DEC never occurred. The PDP can is
   respond free to the requestor accordingly. modify its decision and try again.

   The PEP can report to the PDP the local 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 referenced by identified via the
   associated Client Handle
   associated with the request state and in the client specific data
   identifier. 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 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 at this time 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 information, 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 the synchronization, the client can assume the server
   recognizes it and the current state at the PEP is correct. Any correct, so a
   REQ message need not be sent. Still, any state changes which
   occurred at the PEP while that the connection was
   lost 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. On the other hand, if re-synchronization Whenever re-
   synchronization is requested, the PEP MUST reissue any REQ
   messages it generated
   during initial connection establishment 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 request active request-
   state at the PEP is to be used for policy decisions. If the PEP
   cannot re-
   connect re-connect in some pre-specified period of time, the request state is all
   installed Request-States are to be deleted and the their associated
   Handles removed. The same holds true for the PDP; upon detecting a
   failed TCP connection, the time-out timer is started for the request state all
   Request-States associated with the PEP and the state is these states are
   removed after the administratively specified period without a

  7.1. Security Considerations

   The use of COPS for Policy Provisioning introduces no new security
   issues over the base COPS protocol [COPS]. The security mechanism
   described in that document should be deployed in a COPS-PR

8. 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 and Fine, Scott Hahn. Hahn,
   and Carol Bell.

9. 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.

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

[ASN1]    Information processing systems - Open Systems
          Interconnection, "Specification of Abstract Syntax Notation
          One (ASN.1)", International Organization for
          Standardization, International Standard 8824, December

[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] S. Blake, D. Black, M. Carlson, E. Davies, Z. Wang, W.
          Weiss, "An Architecture for Differentiated Service," RFC
          2475, December 1998.

[PIB]     M. Fine, K. McCloghrie, R. Sahita, S. Hahn, K. Chan, A.
          Smith, "An
          Initial Quality of Service J. Seligson, "Framework Policy Information Base for
          COPS-PR Clients and Servers", draft-mfine-cops-pib-02.txt,
          October 1999.

V2SMI] Base",
          draft-ietf-rap-frameworkpib-00.txt, July 2000.

[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

[RFC2234] D. Crocker, P. Overell, " Augmented BNF for Syntax
          Specifications: ABNF", RFC 2234, November 1997.

10. Author Information

Francis Reichmeyer                  IPHighway Inc.
Phone: (201) 585-0800               Parker Plaza, 16th Floor
Email:          400 Kelby St.
                                    Fort-Lee, NJ 07024
Shai Herzog
Phone: (201) 585-0800

Kwok Ho Chan                        Nortel Networks, Inc.
Phone: (978) 916-8175 288-8175               600 Technology Park Drive
EMail:    Billerica, MA 01821

David Durham                        Intel
Phone: (503) 264-6232               2111 NE 25th Avenue
Email:       Hillsboro, OR 97124

Raj Yavatkar
Phone: (503) 264-9077

Silvano Gai                         Cisco Systems, Inc.
Phone: (408) 527-2690               170 Tasman Dr.
Email:               San Jose, CA 95134-1706

Keith McCloghrie
Phone: (408) 526-5260

Andrew Smith                        Extreme Networks
Phone: +1 408 579 2821              3585 Monroe St.
Email:   Santa Clara CA 95051
415 345 1827 fax

John Seligson                       Nortel Networks, Inc.
Phone: (408) 495-2992               4401 Great America Parkway   Santa Clara, CA 95054

11. Full Copyright Notice

Copyright (C) The Internet Society (1997).  All Rights Reserved.

This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works.  However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
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followed, or as required to translate it into languages other than

The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.

This document and the information contained herein is provided on an