Connectivity Provisioning Negotiation Protocol (CPNP)
draft-boucadair-connectivity-provisioning-protocol-06

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Authors Mohamed Boucadair  , Christian Jacquenet  , Dacheng Zhang 
Last updated 2014-09-02
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Network Working Group                                       M. Boucadair
Internet-Draft                                              C. Jacquenet
Intended status: Experimental                             France Telecom
Expires: March 6, 2015                                          D. Zhang
                                                     Huawei Technologies
                                                      September 02, 2014

         Connectivity Provisioning Negotiation Protocol (CPNP)
         draft-boucadair-connectivity-provisioning-protocol-06

Abstract

   This document specifies the Connectivity Provisioning Negotiation
   Protocol (CPNP) which is used to facilitate the dynamic negotiation
   of service parameters between a Customer and a Provider.

   CPNP is a generic protocol that can be used for various negotiation
   purposes that include (but are not necessarily limited to)
   connectivity provisioning services, storage facilities, CDN (Content
   Delivery Networks) footprint, etc.  CPNP can be extended with new
   Information Elements.

Requirements Language

   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 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on March 6, 2015.

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Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  CPNP Functional Elements  . . . . . . . . . . . . . . . . . .   5
   4.  Order Processing Models . . . . . . . . . . . . . . . . . . .   6
   5.  Sample Use Cases  . . . . . . . . . . . . . . . . . . . . . .   7
   6.  Deployment Models . . . . . . . . . . . . . . . . . . . . . .   8
   7.  CPNP Negotiation Model  . . . . . . . . . . . . . . . . . . .   9
   8.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Client/Server Communication . . . . . . . . . . . . . . .  11
     8.2.  Server Discovery  . . . . . . . . . . . . . . . . . . . .  11
     8.3.  Policy Configuration on the CPNP Server . . . . . . . . .  11
     8.4.  CPNP Session  . . . . . . . . . . . . . . . . . . . . . .  13
     8.5.  Extended CPNP Session . . . . . . . . . . . . . . . . . .  13
     8.6.  CPNP Transaction  . . . . . . . . . . . . . . . . . . . .  14
     8.7.  CPNP Operations . . . . . . . . . . . . . . . . . . . . .  14
     8.8.  Connectivity Provisioning Documents . . . . . . . . . . .  15
     8.9.  Child Provisioning Quotation Orders . . . . . . . . . . .  16
     8.10. Negotiations with Multiple CPNP Servers . . . . . . . . .  17
     8.11. State Management  . . . . . . . . . . . . . . . . . . . .  17
       8.11.1.  On the Client Side . . . . . . . . . . . . . . . . .  17
       8.11.2.  On the Server Side . . . . . . . . . . . . . . . . .  20
     8.12. CPNP Timers . . . . . . . . . . . . . . . . . . . . . . .  22
   9.  CPNP Objects  . . . . . . . . . . . . . . . . . . . . . . . .  22
     9.1.  Attributes  . . . . . . . . . . . . . . . . . . . . . . .  22
       9.1.1.  CUSTOMER_AGREEMENT_IDENTIFIER . . . . . . . . . . . .  22
       9.1.2.  PROVIDER_AGREEMENT_IDENTIFIER . . . . . . . . . . . .  22
       9.1.3.  TRANSACTION_ID  . . . . . . . . . . . . . . . . . . .  23
       9.1.4.  SEQUENCE_NUMBER . . . . . . . . . . . . . . . . . . .  23
       9.1.5.  NONCE . . . . . . . . . . . . . . . . . . . . . . . .  23
       9.1.6.  EXPECTED_RESPONSE_TIME  . . . . . . . . . . . . . . .  23
       9.1.7.  EXPECTED_OFFER_TIME . . . . . . . . . . . . . . . . .  23

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       9.1.8.  VALIDITY_OFFER_TIME . . . . . . . . . . . . . . . . .  24
       9.1.9.  CONNECTIVITY_PROVISIONING_DOCUMENT  . . . . . . . . .  24
       9.1.10. Information Elements  . . . . . . . . . . . . . . . .  24
     9.2.  Operation Messages  . . . . . . . . . . . . . . . . . . .  26
       9.2.1.  QUOTATION . . . . . . . . . . . . . . . . . . . . . .  26
       9.2.2.  PROCESSING  . . . . . . . . . . . . . . . . . . . . .  26
       9.2.3.  OFFER . . . . . . . . . . . . . . . . . . . . . . . .  28
       9.2.4.  ACCEPT  . . . . . . . . . . . . . . . . . . . . . . .  28
       9.2.5.  ACK . . . . . . . . . . . . . . . . . . . . . . . . .  28
       9.2.6.  DECLINE . . . . . . . . . . . . . . . . . . . . . . .  29
       9.2.7.  CANCEL  . . . . . . . . . . . . . . . . . . . . . . .  30
       9.2.8.  WITHDRAW  . . . . . . . . . . . . . . . . . . . . . .  30
       9.2.9.  UPDATE  . . . . . . . . . . . . . . . . . . . . . . .  31
       9.2.10. FAIL  . . . . . . . . . . . . . . . . . . . . . . . .  32
   10. Message Validation  . . . . . . . . . . . . . . . . . . . . .  33
     10.1.  On the Client Side . . . . . . . . . . . . . . . . . . .  33
     10.2.  On the Server Side . . . . . . . . . . . . . . . . . . .  34
   11. Theory of Operation . . . . . . . . . . . . . . . . . . . . .  35
     11.1.  Client Behavior  . . . . . . . . . . . . . . . . . . . .  35
       11.1.1.  Order Negotiation Cycle  . . . . . . . . . . . . . .  35
       11.1.2.  Order Withdrawal Cycle . . . . . . . . . . . . . . .  37
       11.1.3.  Order Update Cycle . . . . . . . . . . . . . . . . .  37
     11.2.  Server Behavior  . . . . . . . . . . . . . . . . . . . .  37
       11.2.1.  Order Processing . . . . . . . . . . . . . . . . . .  37
       11.2.2.  Order Withdrawal . . . . . . . . . . . . . . . . . .  39
       11.2.3.  Order Update . . . . . . . . . . . . . . . . . . . .  39
     11.3.  Sequence Numbers . . . . . . . . . . . . . . . . . . . .  39
     11.4.  Message Re-Transmission  . . . . . . . . . . . . . . . .  40
   12. Operational Guidelines  . . . . . . . . . . . . . . . . . . .  40
     12.1.  Logging on the CPNP Server . . . . . . . . . . . . . . .  40
     12.2.  Business Guidelines & Objectives . . . . . . . . . . . .  40
   13. Security Considerations . . . . . . . . . . . . . . . . . . .  41
   14. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  42
   15. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  43
   16. References  . . . . . . . . . . . . . . . . . . . . . . . . .  43
     16.1.  Normative References . . . . . . . . . . . . . . . . . .  43
     16.2.  Informative References . . . . . . . . . . . . . . . . .  43
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  44

1.  Introduction

   This document defines the Connectivity Provisioning Negotiation
   Protocol (CPNP) that is meant to dynamically exchange and negotiate
   the connectivity provisioning parameters, and other service-specific
   parameters, between a Customer and a Provider.  CPNP is a tool that
   introduces automation in the service negotiation and activation
   procedures, thus fostering the overall service delivery process.

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   CPNP can be seen as a component of the dynamic negotiation meta-
   domain described in Section 3.4 of [RFC7149].

   CPNP is a generic protocol that can be used for other negotiation
   purposes than connectivity provisioning.  For example, CPNP can be
   used to request extra storage resources, to extend the footprint of a
   CDN (Content Delivery Networks), to enable additional features from a
   cloud Provider, etc.  CPNP can be extended with new Information
   Elements (IEs).

   [RFC7297] describes a Connectivity Provisioning Profile (CPP)
   template to capture connectivity requirements to be met by a
   transport infrastructure for the delivery of various services such as
   Voice over IP, IPTV, and VPN services.  The CPP document defines the
   set of IP transfer parameters that reflect the guarantees that can be
   provided by the underlying transport network together with a
   reachability scope and capacity needs.  CPNP uses the CPP template to
   encode connectivity provisioning clauses.

   As a reminder, several proposals have been made in the past by the
   community (e.g., COPS-SLS, SrNP (Service Negotiation Protocol), DSNP
   (Dynamic Service Negotiation Protocol, RNAP (Resource Negotiation and
   Pricing Protocol), SNAP (Service Negotiation and Acquisition
   Protocol), etc.).  None of these proposals has been standardized by
   IETF.  It is out of the scope of this document to elaborate on the
   differences between CPNP and the aforementioned proposals.

   This document is organized as follows:

   o  Section 3 defines functional elements involved in CPNP exchanges.
   o  Section 4 introduces several order processing models and precises
      those that are targeted by CPNP.
   o  Section 5 enumerates a non-exhaustive list of use cases that would
      benefit from CPNP.
   o  Section 5 discusses some CPNP deployment models.
   o  Section 7 presents CPNP negotiation model.
   o  Section 8 provides an overview of the protocol.
   o  Section 9 specifies CPNP objects.
   o  Section 10 describes CPNP message validation procedure.
   o  Section 11 specifies the behavior of involved CPNP functional
      elements.
   o  Section 12 discusses some operational guidelines.

2.  Terminology

   This document makes use of the following terms:

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   o  Customer: is a business role which denotes an entity that is
      involved in the definition and the possible negotiation of a
      contract, including Connectivity Provisioning Agreement, with a
      Provider.  A connectivity provisioning contract is captured in a
      dedicated CPP template, which specifies (among other information):
      the sites to be connected, border nodes, outsourced operations
      (e.g., routing, force via points).  The right to invoke the
      subscribed service may be delegated by the Customer to third-party
      End Users, or brokering services.

   o  Network Provider (or Provider): owns and administers one or many
      transport domain(s) (typically Autonomous System (AS)) composed of
      IP switching and transmission resources (e.g., routing, switching,
      forwarding, etc.).  Network Providers are responsible for ensuring
      connectivity services (e.g., offering global or restricted
      reachability).  Connectivity services offered to Customers are
      captured in contracts from which are derived the technology-
      specific clauses and policies to be enforced by the components
      involved in the connectivity service delivery.  Offered
      connectivity services are not restricted to IP.

   o  Quotation Order: denotes a request made by the Customer to the
      Provider that includes a set of requirements.  These requirements
      can be captured as negotiation parameters that may have fixed,
      loosely defined or a combination thereof.

   o  Offer: refers to a response made by the Provider to the Customer
      as an answer to a quotation order.

   o  Agreement: refers to an order placed by the Customer and accepted
      by the Provider.  Note also that an order may be triggered by an
      offer made by the Provider.

3.  CPNP Functional Elements

   The following functional elements are defined:

   o  CPNP client (or client): denotes a software instance that sends
      CPNP requests and receives CPNP responses.  The current operations
      that can be performed by a CPNP client are listed below:

      1.  Create a quotation order (Section 11.1.1).
      2.  Cancel an ongoing quotation order under negotiation
          (Section 11.1.1).
      3.  Withdraw an agreement (Section 11.1.2).
      4.  Update an agreement (Section 11.1.3).
      5.  Accept an offer made by a server (Section 11.1.1)

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   o  CPNP server (or server): denotes a software instance that receives
      CPNP requests and sends back CPNP responses accordingly.  The CPNP
      server is responsible for the following operations:

      1.  Quotation order handling (Section 11.2.1).
      2.  Cancel an ongoing quotation order (Section 11.2.2).
      3.  Handling of an order withdrawal (Section 11.2.3).
      4.  Make an offer (Section 11.2.1).

4.  Order Processing Models

   There are basically three models for customer's order processing
   purposes:

   1.  Frozen model: The Customer cannot negotiate the parameters of the
       service delivered by a Provider.  After consulting a service
       portfolio, the Customer selects the offer he/she wants to
       subscribe and places an order to the Provider.  Order handling is
       quite simple on the Provider side because the service is not
       customized as per Customer's requirements, but rather pre-
       designed to target a group of customers having similar
       requirements (and who therefore share the same Customer
       Provisioning Profile).

   2.  Announcement model: The Provider proceeds to the announcement of
       a set of services templates.  The Customer can then initiate a
       negotiation cycle using these templates to prepare its request
       order.

   3.  Negotiation-based model: Unlike the frozen model, the Customer
       documents his/her requirements in some kind of request for
       quotation which is then sent to one or several Providers.
       Solicited Providers then check whether they can address these
       requirements or not, and get back to the Customer accordingly,
       possibly with an offer that may not exactly match customer's
       requirements (e.g., a 100 Mbps connection cannot be provisioned
       given the amount of available resources, but an 80 Mbps
       connection can be provided).  A negotiation between the Customer
       and the Provider then follows, and an order is placed by the
       Customer eventually, upon completion of the negotiation phase.
       The outcome of the negotiation is recorded in an agreement
       document.

   Even if the frozen model could also yield the instantiation of a CPP
   template and CPNP could be used to display the said CPP to the
   Customer and confirm the order is being processed/delivered, etc.,
   this document focuses on the negotiation-based model.

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   Order processing management on the Network Provider's side is usually
   connected with the following functional blocks:

   o  Network Provisioning (including Order Activation, Network
      Planning, etc.)
   o  AAA
   o  Sales-related functional blocks (e.g., billing, Customers credit
      checks validation, etc.)
   o  Network Impact Analysis

   CPNP does not assume any specific knowledge about these functional
   blocks, but the instantiation of the connectivity provisioning
   requests may be conditioned by the information manipulated by some of
   these blocks.  For example, the resources that can be allocated to
   accommodate the Customer's requirements may depend on the network
   planning policy as well as the number of orders to be processed
   simultaneously over a given period of time.

   This document does not elaborate on how Customers are identified and
   managed by the Provider's Information System.

5.  Sample Use Cases

   A list of CPNP use cases is provided below:

   1.  [RFC4176] introduces the L3VPN Service Order Management
       functional block which is responsible for managing the requests
       initiated by the Customers and tracks the status of the
       completion of the related operations.  CPNP can be used between
       the Customer and the Provider to negotiate L3VPN service
       parameters.  A CPNP server could therefore be part of the L3VPN
       Service Order Management functional block discussed in [RFC4176].

   2.  CPNP can be used between two adjacent domains to deliver IP
       interconnect services (e.g., enable, update, disconnect).  For
       example, two ASes can be connected via several interconnection
       points.  CPNP can be used between these ASes to upgrade existing
       links, request additional resources, provision a new
       interconnection point, etc.

   3.  An integrated Provider can use CPNP to rationalize connectivity
       provisioning needs related to its service portfolio.  A CPNP
       server function is used by network operations teams.  A CPNP
       interface to invoke CPNP negotiation cycles is exposed to service
       management teams.

   4.  Service Providers can initiate connectivity provisioning requests
       towards Network Providers using CPNP.  Multiple CPNP ordering

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       cycles can be initiated by a Service Provider towards multiple
       Network Providers.  Only a subset of these orders may be put into
       effect.

   5.  CPNP can be used in M2M environments to dynamically subscribe to
       M2M services (e.g., access to data retrieved by a set of sensors,
       extend sensor coverage, etc.).

   6.  A Provider offering cloud services can expose a CPNP interface to
       allow Customers to dynamically negotiate the features they want
       to subscribe to.  These features can be for instance: request
       additional storage resources, enable security filters, etc.

   7.  In the inter-cloud context (also called cloud of clouds or cloud
       federation), CPNP can be used to reserve external resources in
       other clouds locations.  These resources can be networking
       resources for instance.

   8.  CDN Providers can use CPNP to extend their footprint by
       interconnecting their CDN infrastructure [RFC6770] (see
       Figure 1).

          ,--,--,--.             ,--,--,--.
       ,-'          `-.       ,-'          `-.
      (CDN Provider 'A')=====(CDN Provider 'B')
       `-.  (CDN-A) ,-'       `-. (CDN-B)  ,-'
          `--'--'--'             `--'--'--'

                       Figure 1: CDN Interconnection

6.  Deployment Models

   Several CPNP deployment models can be envisaged.  Two examples are
   listed below:

   o  The Customer deploys a CPNP client while one or several CPNP
      servers are deployed by the Provider.
   o  The Customer does not enable any CPNP client.  The Provider
      maintains a Customer Order Management portal.  The Customer can
      initiate connectivity provisioning quotation orders via the
      portal; appropriate CPNP messages are then generated and sent to
      the relevant CPNP server.  In this model, both the CPNP client and
      CPNP server are under the responsibility of the same
      administrative entity (i.e., Network Provider).

   Once the negotiation of connectivity provisioning parameters is
   completed and an order has been placed by the Customer accordingly,
   the actual network provisioning operations are initiated.  The

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   specification of corresponding dynamic resource allocation and policy
   enforcement schemes, as well as how CPNP servers interact with
   network provisioning functional blocks are out of the scope of this
   document.

   This document does not make any assumption about the CPNP deployment
   model either.

7.  CPNP Negotiation Model

   This document assumes that only the customer can call for an
   agreement.  Allowing the Provider to call for an agreement would be
   possible in theory but this is not a key functionality in this
   document.  It was tempting to define an explicit message to call for
   agreement, but this document assumes an implicit approach that
   assumes accepting an offer made by the Provider is signal to call for
   agreement; no need to overload the protocol logic.

   CPNP adopts a Quotation Order/Offer/Answer model where:

   1.  The client specifies its requirements via a Provision Quotation
       Order (PQO).

       *  The provisioning quotation order may include clauses with
          fixed values, loosely defined values, or a combination
          thereof.
       *  A Customer may be engaged simultaneously in negotiations with
          multiple Providers.
   2.  The server declines the PQO, makes an offer to address the
       requirements of the PQO, or suggests a counter-proposal that
       partially addresses the requirements of the PQO.  Note, a server
       may need to negotiate with other Provider(s) as part of
       negotiations with a Customer (cascaded negotiations, see
       Section 8.9).
   3.  The client either accepts or declines the offer.  Accepting the
       offer implies a call for agreement.

   CPNP relies on various timers to achieve its operations.  These
   timers are used to guide the negotiation logic at both client and
   server sides, particularly when the client is involved in multiple
   negotiations with several servers or when the upstream is, in its
   turn, involved in negotiations with other servers to process a given
   quotation order.

   CPNP allows a server to request for more time.  This request can be
   accepted or rejected by the server.

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   The server may support the optional functionality to publish
   available services to the clients.  Dedicated templates can be
   defined for the purpose of service announcements.  The client will
   use these templates to initiate its CPNP negotiation cycle.

   Only one Offer/Answer stage is assumed within one single CPNP
   negotiation cycle.  Nevertheless, multiple CPNP negotiation cycles
   can be undertaken by the CPNP client (see Figure 2).

   The model is flexible as it accommodates changes such as conditions
   that may evolve over time (e.g., introduction of an additional VPN
   site).

   +------+                  +------+ +------+                  +------+
   |Client|                  |Server| |Client|                  |Server|
   +------+                  +------+ +------+                  +------+
      |=====Quotation Order=====>|      |=====Quotation Order======>|
      |<====Make an offer========|      |<=====Make an offer========|
      |=========Accept==========>|      |=========Decline==========>|

     1-Step Successful Negotiation         1-Step Failed Negotiation
               Cycle                               Cycle

   +------+                  +------+ +------+                  +------+
   |Client|                  |Server| |Client|                  |Server|
   +------+                  +------+ +------+                  +------+
      |===Quotation Order(a)====>|       |===Quotation Order(i)====>|
      |<====Make an offer========|       |<=====Make an offer=======|
      |========Decline==========>|       |=========Decline=========>|
      |===Quotation Order(b)====>|       |===Quotation Order(j)====>|
      |<====Make an offer========|       |<=====Make an offer=======|
      |=========Accept==========>|       |=========Decline=========>|
                                         |===Quotation Order(k)====>|
                                         |<=====Make an offer=======|
                                         |=========Decline=========>|
                                         |===Quotation Order(l)====>|
                                         |<==Fail to make an offer==|

       N-Step Negotiation Cycle:         N-Step Negotiation Cycle:
         Successful Negotiation              Failed Negotiation

                   Figure 2: Overall Negotiation Process

8.  Protocol Overview

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8.1.  Client/Server Communication

   CPNP is a client/server protocol which runs over UDP.  No permanent
   CPNP session needs to be maintained between the client and the
   server.  There is no need to run CPNP over a reliable transport mode
   because CPNP messages are acknowledged.

   The server uses CPNP_PORT (see Section 14) to bind the CPNP service.
   CPNP client sends messages to CPNP_PORT.  The same port is used as
   the source port of the request sent to the server to document service
   requirements, and must be used by the client to listen to messages
   sent by the server.

   CPNP is independent of the IP address family.

8.2.  Server Discovery

   The CPNP client can be configured with the CPNP server using manual
   or dynamic configuration means.  For example, Providers may configure
   dedicated SRV records ([RFC2782]).

   Discussions about how the client discovers its server(s) are out of
   the scope of this document.  The document assumes a CPNP server can
   be reached by the CPNP client, thanks to some configuration means.

8.3.  Policy Configuration on the CPNP Server

   As an input to the CPNP server's decision-making process, the CPNP
   server may be connected to various external modules such as: Customer
   Profiles, Network Topology, Network Resource Management, Orders
   Repository, AAA or Network Provisioning Manager (an example is shown
   in Figure 3).

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          . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
          .Business & Administrative Management                   .
          .+------------------------++---------------------------+.
          .| Business Guidelines    ||    Billing & Charging     |.
          .+-----------+------------++-----------+---------------+.
          .            |                         |                .
          .            +-------------------+     |                .
          . . . . . . . . . . . . . . . . .|. . .|. . . . . . . . .
          . . . . . . . . . . . . . . . . .|. . .|. . . . . . . . .
          .Order Handling Management       |     |                .
          . +-------------------+  +-------+-----+--------------+ .
          . |Network Topology DB+--+        CPNP Server         | .
          . +-------------------+  +-+---+---+---+---+-----+----+ .
          .                          |   |   |   |   |     |      .
          . +------------------------+-+ |   |   |   |     |      .
          . |   Network Dimensioning   | |   |   |   |     |      .
          . |        & Planning        | |   |   |   |     |      .
          . +--------------------------+ |   |   |   |     |      .
          . +----------------------------+-+ |   |   | +---+----+ .
          . |                              | |   |   | |   AAA  | .
          . |   Network       +------------+ |   |   | +--------+ .
          . |  Resource       | +------------+-+ | +-+----------+ .
          . |  Management     | |   Customer   | | |   Orders   | .
          . |                 | |   Profiles   | | | Repository | .
          . +-----------------+ +--------------+ | +------------+ .
          . . . . . . . . . . . . . . . . . . . .|. . . . . . . . .
          +--------------------------------------+----------------+
          |             Network Provisioning Manager              |
          +-------------------------------------------------------+

           Figure 3: Order Handling Management Functional Block

   These external modules provide inputs to the CPNP server, so that it
   can:

   o  Check whether a customer is entitled to initiate the provisioning
      quotation request.
   o  Check whether a customer is entitled to cancel the order
   o  Check whether administrative data (e.g., billing-related
      information) have been verified before starting handling the
      request
   o  Check whether network capacity is available or additional capacity
      is required
   o  Receive guidelines from network design and sales blocks (e.g.,
      cost, increase network usage, threshold of how many CPP templates
      can be processed over a given period of time as a function of the
      nature of the service to be delivered, etc.)
   o  Transfer completed orders to network provisioning blocks

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   o  Etc.

   The above list of CPNP server operations is not exhaustive.

   The following order handling modes can be also configured on the
   server:

   1.  Fully automated mode: This mode does not require any action from
       the administrator when receiving a request for a service.  The
       server can execute its decision-making process related to the
       orders received and generate corresponding offers.

   2.  Administrative validation checking: Some or all server's
       operations are subject to administrative validation procedures.
       This mode requires an action from the administrator for every
       request received by the CPNP server.  CPNP methods which can be
       automatically handled or subject to one or several validation
       administrative checks can be configured on the server.

8.4.  CPNP Session

   Both the client and server maintain the following CPNP transport
   session information:

   A CPNP session is identified by the following items:

   o  IP address of the client
   o  Client's port number
   o  IP address of the server
   o  Server's port number

8.5.  Extended CPNP Session

   An extended PQO session denotes a 4-uplet defined as follows:

   o  CPNP session
   o  Incremented Sequence Number (see Section 11.3)
   o  Customer Agreement Identifier: That is a unique identifier
      assigned to the order under negotiation by the client (see
      Section 9.1.1).  This identifier will also be used to identify the
      agreement that will result from a successful negotiation.
   o  Provider Agreement Identifier: That is a unique identifier
      assigned to the order under negotiation by the server (see
      Section 9.1.2).  This identifier will also be used to identify the
      agreement that will result from a successful negotiation.
   o  Transaction-ID (see Section 9.1.3)

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8.6.  CPNP Transaction

   A CPNP transaction occurs between a client and a server and comprises
   all CPNP messages, from the first request sent by the client to the
   server until a final response sent by the server to the client and
   which completes the transaction.  The CPNP transaction is bound to a
   CPNP session.

   Because multiple CPNP transactions can be maintained by the CPNP
   client, the client must assign an identifier to uniquely identify a
   given transaction.  This identifier is denoted as Transaction-ID.

   The Transaction-ID must be randomly assigned be the CPNP client,
   according to the best current practice for generating random numbers
   [RFC4086] that cannot be guessed easily.  Transaction-ID is used as
   part of the validation of CPNP responses received by the client.

   The client needs to randomly select a sequence number and set it in
   the first CPNP message and in the outgoing sequence number maintained
   locally.  This number is then incremented fro each request within the
   same CPNP transaction.

8.7.  CPNP Operations

   The current CPNP operations are listed below.  They may be augmented,
   depending on the nature of some transactions or because of security
   considerations that may suggest a CPNP client/server authentication
   phase before negotiation begins.

   o  QUOTATION: This operation is used to initiate a provisioning
      quotation order.  Upon receipt of a QUOTATION request, the server
      may response with a PROCESSING, OFFER or a FAIL message.  A
      QUOTATION-initiated transaction can be terminated by an OFFER or
      FAIL message.
   o  PROCESSING: This operation is used to inform the remote party the
      message was received and that the order quotation or the offer is
      being processed.  This message can also be issued by a server to
      request more time.  The client replies with an ACK message if more
      time is granted, or with a FAIL message to signal no time
      extension is granted.
   o  OFFER: This operation is used by the server to inform the client
      about an offer that is supposed to best accommodate the
      requirements indicated in the QUOTATION message.
   o  ACCEPT: This operation is used to confirm the acceptance of an
      offer made by the server.  This message is an explicit call for
      agreement.  An agreement is reached when an ACK is received from
      the server, which is likely.  A server that rejects an offer it
      already made is unlikely.

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   o  ACK: This operation is used by the server to acknowledge the
      receipt of an ACCEPT or WITHDRAW message, or by the client to
      confirm more time is granted for the processing of a given
      quotation order.
   o  DECLINE: This operation is used by a client to reject an offer
      made by the server.
   o  CANCEL: This operation is used by the client to cancel an ongoing
      provisioning quotation order.
   o  WITHDRAW: This operation is used by the client to withdraw an
      agreement.
   o  UPDATE: This operation is used by the client to update an existing
      connectivity provisioning order.  For example, this method can be
      invoked to add a new site.  This method will trigger a new
      negotiation cycle.
   o  FAIL: This operation is used by the server when it cannot
      accommodate the requirements documented in the PQO conveyed in the
      QUOTATION message or to inform the client about an error
      encountered when processing the received message.  This message is
      also used by the client to reject a more time request received
      from the server.  The message includes the status code which
      provides more information about the error.

   CPNP primitives are service-independent.  This document specifies
   objects that are required for connectivity provisioning negotiation
   (see Section 8.8).  Additional service-specific objects to be carried
   in CPNP messages can be defined in the future to accommodate other
   deployment needs.

8.8.  Connectivity Provisioning Documents

   CPNP makes use of several flavors of Connectivity Provisioning
   Documents (CPD).  These documents follow the CPP template described
   in [RFC7297].

   o  Requested Connectivity Provisioning Document: refers to the CPD
      included by a CPNP client in a QUOTATION request.
   o  Offered Connectivity Provisioning Document: This document is
      included by a CPNP server in an OFFER message.  This information
      reflects the proposal of the server to accommodate all or a subset
      of the clauses depicted in a CPD.  A validity time is associated
      with the offer.
   o  Agreed Connectivity Provisioning Document: If the client accepts
      the offer, the offered CPD is included in an ACCEPT message.  This
      CPD is also included in an ACK message.

   Figure 4 shows a typical CPNP negotiation cycle and the use of
   Connectivity Provisioning Documents.  There are two CPNP transactions
   (Section 8.6) in this negotiation cycle: the one from QUOTATION to

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   its final response which is OFFER, and the second one starting with
   an ACCEPT message while its final response ACK.

   +------+                              +------+
   |Client|                              |Server|
   +------+                              +------+
      |======QUOTATION (Requested CPD)=====>|
      |<============PROCESSING==============|
      |<========OFFER (Offered CPD)=========|
      |=============PROCESSING=============>|
      |=========ACCEPT (Agreed CPD)========>|
      |<=========ACK (Agreed CPD)===========|

               Figure 4: Connectivity Provisioning Documents

   A provisioning document can include parameters with fixed values,
   loosely defined values, or a combination thereof.  A provisioning
   document is said to be concrete if all clauses have fixed values.

   A typical example of the negotiation would be to include a quotation
   order with loosely defined parameters, and then include concrete
   provisioning document when calling for the agreement.

8.9.  Child Provisioning Quotation Orders

   If the server detects network resources from another Network Provider
   need to be allocated in order to accommodate the requirements
   described in a PQO (e.g., context of an inter-domain VPN service
   where additional PE router resources need to be allocated), the
   server may generate child PQOs to request the appropriate network
   provisioning operations (see Figure 5).  In such situation, the
   server behaves as a CPNP client.  The server associates the parent
   order with its child PQOs.  This is typically achieved by locally
   adding the reference of the child PQO to the parent order.

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   +------+            +--------+          +--------+
   |Client|            |Server A|          |Server B|
   +------+            +--------+          +--------+
      |                    |                    |
      |=====QUOTATION=====>|                    |
      |<====PROCESSING=====|                    |
      |                    |=====QUOTATION=====>|
      |                    |<====PROCESSING=====|
      |                    |<=======OFFER=======|
      |                    |=====PROCESSING====>|
      |                    |=======ACCEPT======>|
      |                    |<=======ACK=========|
      |<=======OFFER=======|                    |
      |=====PROCESSING====>|                    |
      |=======ACCEPT======>|                    |
      |<=======ACK=========|                    |

                     Figure 5: Example of Child Orders

8.10.  Negotiations with Multiple CPNP Servers

   A CPNP client may undertake multiple negotiations with several
   servers.  This multiple negotiation can lead to one or many
   agreements.

   The CPNP client may use the outcome of the individual ongoing
   negotiations as an input to its decision-making process.  Timing is
   very important for the parallel negotiation context.

8.11.  State Management

   Both the client and the server maintain repositories to store ongoing
   orders.  How these repositories are maintained is deployment-
   specific.  It is out of scope of this document to elaborate on such
   considerations.Timestamps are also logged to track state change.
   Tracking may be needed for various reasons (including regulatory
   ones).

8.11.1.  On the Client Side

   The following lists the states which can be associated with a given
   order on the client's side:

   o  Created: when the order has been created.  It is not handled by
      the client until the administrator allows to process it.
   o  AwaitingProcessing: when the administrator ordered to process an
      order and this order is not handled yet.

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   o  PQOSent: when the PQO has been sent to the server.
   o  ServerProcessing: when the server has confirmed the receipt of the
      order.
   o  OfferReceived: when an offer has been received from the server.
   o  OfferProcessing: when a received offer is currently processed by
      the client.
   o  AcceptSent: when the client confirmed the offer to the server.
   o  AcceptAck: when the offer is acknowledged by the server.
   o  Cancelled: when the order has failed or has been cancelled.

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   +------------------+
   |     Created      |-----------------+
   +------------------+                 |
           |                            |
           v                            |
   +------------------+                 |
   |AwaitingProcessing|----------------+|
   +------------------+                ||
           |                           ||
        QUOTATION                      ||
           v                           ||
   +------------------+                ||
   |     PQOSent      |---CANCEL------+||
   +------------------+               vvv
           |                        +-----+
       PROCESSING                   |     |
           v                        |     |
   +------------------+   CANCEL    |  C  |
   | ServerProcessing |------------>|  A  |
   +------------------+    FAIL     |  N  |
           |                        |  C  |
           |                        |  E  |
         OFFER                      |  L  |
           |                        |  L  |
           v                        |  E  |
   +------------------+             |  D  |
   |  OfferReceived   |---CANCEL--->|     |
   +------------------+             |     |
           | PROCESSING             +-----+
           v                          ^^^
   +------------------+               |||
   |  OfferProcessing |---DECLINE-----+||
   +------------------+                ||
           | ACCEPT                    ||
           v                           ||
   +------------------+                ||
   |    AcceptSent    |---CANCEL-------+|
   +------------------+                 |
           | ACK                        |
           v                            |
   +------------------+                 |
   |   AcceptAck      |---WITHDRAW------+
   +------------------+

             Figure 6: CPNP Finite State Machine (Client Side)

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8.11.2.  On the Server Side

   The following lists the states which can be associated with a given
   order on the server's side:

   o  PQOReceived: when the provisioning quotation order request has
      been received from the client.
   o  AwaitingProcessing: when the order request is being processed by
      the server.  An action from the server administrator may be
      needed.
   o  OfferProposed: when the request has been successfully handled and
      an offer has been sent to the requesting client.
   o  ProcessingReceived: when the server received a PROCESSING for an
      offer sent to the client.
   o  AcceptReceived: when the server received a confirm for the offer
      from the client.
   o  AcceptAck: when the server acknowledged the offer to the client.
   o  Cancelled: when the order request has failed or has been
      cancelled.  Associate resources must be released in the latter
      case.
   o  ChildCreated: when a child PQO has been created because resources
      from another network provider are needed.
   o  ChildPQOSent: when a child PQO has been sent to another server.
   o  ChildServerProcessing: when a child PQO is currently processed by
      another server.
   o  ChildOfferReceived: when an offer has been received to a child
      PQO.
   o  ChildOfferProcessing: when a received offer is currently
      processed.
   o  ChildAcceptSent: when the child offer is confirmed to another
      server.
   o  ChildAcceptAck: when the child offer is acknowledged by another
      server.

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                                 +------------------+
           +---------------------|    ChildCreated  |
           |                     +------------------+
           v                            |      ^
   +------------------+                 |      |
   |   ChildPQOSent   |----------------+|      P
   +------------------+                ||      R
           |                           ||      O
        QUOTATION                      ||      V
           v                           ||      I  +--------------------+
   +---------------------+   CANCEL    ||      S  |     PQOReceived    |
   |ChildServerProcessing|------------+||      I  +--------------------+
   +---------------------+    FAIL    vvv      O       |      |
           |                        +-----+    N    CANCEL    |
       PROCESSING                   |     |<---|-------+  PROCESSING
           v                        |     |    |              v
   +------------------+             |     |   +------------------------+
   |ChildOfferReceived|----CANCEL---|  C  |<--|   AwaitingProcessing   |
   +------------------+             |  A  |   +------------------------+
           |                        |  N  |       ^          | OFFER
         OFFER                      |  C  |       | +------------------+
           |                        |  E  |<DECLINE-|   OfferProposed  |
           |                        |  L  |       | +------------------+
           v                        |  L  |       |          |
   +------------------+             |  E  |       |      PROCESSING
   |ChildOfferReceived|---CANCEL----|  D  |       |          v
   +------------------+             |     |       | +------------------+
           |                        |     |<DECLINE-| Proc'ingReceived |
      PROCESSING                    |     |         +------------------+
           |                        +-----+       |          | ACCEPT
           v                         ^^^^^        |          v
   +------------------+              |||||        | +------------------+
   |ChildOfferProc'ing|---DECLINE----+|||+-CANCEL-|-|  AcceptReceived  |
   +------------------+               |||         | +------------------+
           |ACCEPT                    |||         |          |ACK
           v                          |||         |          v
   +------------------+               |||         | +------------------+
   |  ChildAcceptSent |---CANCEL------+|+-WITHDRAW|-|    AcceptAck     |
   +------------------+                |          | +------------------+
           | ACK                       |          |
           v                           |          |
   +------------------+                |          |
   |  ChildAcceptAck  |---WITHDRAW-----+          |
   +------------------+                           |
           |                                      |
           +--------------------------------------+

             Figure 7: CPNP Finite State Machine (Server Side)

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8.12.  CPNP Timers

   CPNP adopts a simple retransmission procedure which relies on a
   retransmission timer denoted as RETRANS_TIMER and maximum retry
   threshold.  The use of RETRANS_TIMER and maximum retry threshold are
   described in Section 11.

   The response timer (RESPONSE_TIMER) is the maximum time, defined in
   seconds, between a provisioning quotation order request sent to the
   server and the corresponding response.  If this timer is exceeded,
   the corresponding quotation order is cancelled by the client.
   Relevant CANCEL messages are generated accordingly.

   An offer expiration timer (EXPIRE_TIMER) represents the maximum time,
   defined in minutes, after which an offer made by the server will be
   invalid.

9.  CPNP Objects

   This section defines CPNP objects using the RBNF format defined at
   [RFC5511].

   This document focuses on connectivity provisioning objects;
   additional Information Elements can be defined in the future.

9.1.  Attributes

9.1.1.  CUSTOMER_AGREEMENT_IDENTIFIER

   CUSTOMER_AGREEMENT_IDENTIFIER is an identifier which is assigned by a
   client to identify an agreement.  This identifier must be unique.
   Rules for assigning this identifier are specific to the client.  The
   value of CUSTOMER_AGREEMENT_IDENTIFIER is included in all CPNP
   messages.

   The client (Customer) assigns an identifier to an order under
   negotiation before an agreemnt si reached.

   The server handles CUSTOMER_AGREEMENT_IDENTIFIER as an opaque value.

9.1.2.  PROVIDER_AGREEMENT_IDENTIFIER

   PROVIDER_AGREEMENT_IDENTIFIER is an identifier which is assigned by a
   server to identify an order.  This identifier must be unique to the
   server.  Rules for assigning this identifier are specific to the
   server.  The value of PROVIDER_AGREEMENT_IDENTIFIER is included in
   all CPNP message, except QUOTATION messages.

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   The server (Provider) assigns an identifier to an order under
   negotiation before an agreemnt si reached.

   The client handles PROVIDER_AGREEMENT_IDENTIFIER as an opaque value.

9.1.3.  TRANSACTION_ID

   This object conveys the Transaction-ID introduced in Section 8.6.

9.1.4.  SEQUENCE_NUMBER

   Sequence Number is a number that is monotonically incremented on
   every new CPNP message within a CPNP transaction.  This number is
   used to avoid reply attacks.

9.1.5.  NONCE

   NONCE is a random value assigned by the CPNP server.  It is
   RECOMMENDED to assign unique NONCE values for each order.

   NONCE is then mandatory to be included in subsequent CPNP client
   operations on the associated order such as: withdraw the order or
   update the order.

   If the NONCE validation checks fail, the server rejects the request
   with a FAIL message including the appropriate failure reason code.

9.1.6.  EXPECTED_RESPONSE_TIME

   This attribute indicates the time by when the client is expecting to
   receive a response, for a PQO, from the server.  If no offer is
   received by then, the client will consider the quotation order as
   rejected.

   EXPECTED_RESPONSE_TIME follows date format specified in [RFC1123].

9.1.7.  EXPECTED_OFFER_TIME

   This attribute indicates the time by when the server is expecting to
   make an offer to the client.  If no offer is received by then, the
   client will consider the order as rejected.

   The server may propose an expected offer time that does not match the
   expected response time indicated in the quotation order message.  The
   client can accept or rejects the proposed expected time by when the
   server will make an offer.

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   The server can always request extra time for its processing, but this
   may be accepted or rejected by the client.

   EXPECTED_OFFER_TIME follows date format specified in [RFC1123].

9.1.8.  VALIDITY_OFFER_TIME

   This attribute indicates the time of validity of an offer made by the
   server.  If the offer is not accepted before this date expires, the
   server will consider the client has rejected the offer; the server
   will silently clear this order.

   VALIDITY_OFFER_TIME follows date format specified in [RFC1123].

9.1.9.  CONNECTIVITY_PROVISIONING_DOCUMENT

   The RBNF format of the Connectivity Provisioning Document is shown
   below:

   <CONNECTIVITY_PROVISIONING_DOCUMENT> ::=
                              <Connectivity Provisioning Component> ...
   <Connectivity Provisioning Component> ::=
                              <CONNECTIVITY_PROVISIONING_PROFILE> ...
   <CONNECTIVITY_PROVISIONING_PROFILE> ::=
                              <Customer Nodes Map>
                              <SCOPE>
                              <QoS Guarantees>
                              <Availability>
                              <CAPACITY>
                              <Traffic Isolation>
                              <Conformance Traffic>
                              <Flow Identification>
                              <Overall Traffic Guarantees>
                              <Routing and Forwarding>
                              <Activation Means>
                              <Invocation Means>
                              <Notifications>
   <Customer Nodes Map> ::=  <Customer Node> ...
   <Customer Node> ::=  <IDENTIFIER>
                        <LINK_IDENTIFIER>
                        <LOCALISATION>

9.1.10.  Information Elements

   An Information Element is an optional object which can be included in
   a CPNP message.

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9.1.10.1.  Customer Description

   The client may include administrative information such as:

   o  Name
   o  Contact Information

   The format of this Information Element is as follows:

   <Customer Description> ::= <NAME> <Contact Information>
   <Contact Information> ::=  <EMAIL_ADDRESS> [<POSTAL_ADDRESS>]
                              [<TELEPHONE_NUMBER> ...]

9.1.10.2.  Provider Description

   The server may include administrative information in an offer such
   as:

   o  Name
   o  AS Number
   o  Contact Information

   The format of this Information Element is as follows:

   <Provider Description> ::= <NAME><Contact Information>[<AS_NUMBER>]

9.1.10.3.  Negotiation Options

   The client may include some negotiation options such as:

   o  Cost: the client may include an empty or a preferred COST
      attribute to request the cost from the server.  The server will
      provide the cost information in the response.
   o  Setup purpose: A client may request to setup a connectivity only
      for testing purposes during a limited period.  The order can be
      extended to become permanent if the client was satisfied during
      the test period.  This operation is achieved using UPDATE method.

   Other negotiation options may be defined in the future.

   The format of this Information Element is as follows:

   <Negotiation Options> ::= [<COST>][<PURPOSE>]

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9.2.  Operation Messages

   This section specifies the RBNF format of CPNP operation messages.

9.2.1.  QUOTATION

   The format of QUOTATION message is shown below:

   <QUOTATION Message> ::=  <VERSION>
                          <METHOD_CODE>
                          <SEQUENCE_NUMBER>
                          <TRANSACTION_ID>
                          <CUSTOMER_AGREEMENT_IDENTIFIER>
                          [<EXPECTED_RESPONSE_TIME>]
                          <REQUESTED_CONNECTIVITY_PROVISIONING_DOCUMENT>
                          [<INFORMATION_ELEMENT>...]

   A QUOTATION message must include an order identifier which is
   generated by the client.  Because several orders can be issued to
   several servers, the QUOTATION message must also include a
   Transaction-ID.

   The message may include an EXPECTED_RESPONSE_TIME which indicates by
   when the client is expecting to receive an offer from the server.
   QUOTATION message must also include a requested connectivity
   provisioning document.

   When the client sends the QUOTATION message to the server, the state
   of the order changes to "PQOSent".

9.2.2.  PROCESSING

   The format of PROCESSING Message is shown below:

   <PROCESSING Message> ::= <VERSION>
                            <METHOD_CODE>
                            <SEQUENCE_NUMBER>
                            <TRANSACTION_ID>
                            <CUSTOMER_AGREEMENT_IDENTIFIER>
                            <PROVIDER_AGREEMENT_IDENTIFIER>
                            [<EXPECTED_OFFER_TIME>]

   Upon receipt of a QUOTATION message, the server proceeds with parsing
   rules (see Section 10).  If no error is encountered, the server
   generates a PROCESSING response to the client to indicate the PQO has
   been received and it is being processed.  The server must generate an
   order identifier which identifies the order in its local order
   repository.  The server MUST copy the content of

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   CUSTOMER_AGREEMENT_IDENTIFIER and TRANSACTION_ID fields as conveyed
   in the QUOTATION message.  The server may include an
   EXPECTED_OFFER_TIME by when it expects to make an offer to the
   client.

   Upon receipt of a PROCESSING message, the client verifies whether it
   has issued a PQO to that server and which contains the
   CUSTOMER_AGREEMENT_IDENTIFIER and TRANSACTION_ID.  If no such PQO is
   found, the PROCESSING message is silently ignored.  If a PQO is
   found, the client may check if it accepts the EXPECTED_OFFER_TIME and
   then, it changes to state of the order to "ServerProcessing".

   If more time is required by the server to process the quotation
   order, it may send a PROCESSING message that includes a new
   EXPECTED_OFFER_TIME.  The client can answer with an ACK message if
   more time is granted (Figure 8) or with a FAIL message if the time
   extension is rejected (Figure 9).

   +------+                              +------+
   |Client|                              |Server|
   +------+                              +------+
      |======QUOTATION (Requested CPD)=====>|
      |<========PROCESSING(time1)===========|
                        ...
      |<========PROCESSING(MoreTime)========|
      |===========ACK (TimeGranted)========>|
                        ...
      |<========OFFER (Offered CPD)=========|
      |=============PROCESSING=============>|
      |=========ACCEPT (Agreed CPD)========>|
      |<=========ACK (Agreed CPD)===========|

             Figure 8: Request more negotiation time: Granted

   +------+                              +------+
   |Client|                              |Server|
   +------+                              +------+
      |======QUOTATION (Requested CPD)=====>|
      |<========PROCESSING(time1)===========|
                        ...
      |<========PROCESSING(MoreTime)========|
      |==========FAIL (TimeRejected)=======>|

             Figure 9: Request more negotiation time: Rejected

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9.2.3.  OFFER

   The format of OFFER message is shown below:

   <OFFER Message> ::= <VERSION>
                       <METHOD_CODE>
                       <SEQUENCE_NUMBER>
                       <TRANSACTION_ID>
                       <CUSTOMER_AGREEMENT_IDENTIFIER>
                       <PROVIDER_AGREEMENT_IDENTIFIER>
                       <NONCE>
                       <VALIDITY_OFFER_TIME>
                       <OFFERED_CONNECTIVITY_PROVISIONING_DOCUMENT>
                       [<INFORMATION_ELEMENT>...]

   The server answers with an OFFER message to a QUOTATION request
   received from the client.  The offer will be considered as rejected
   by the client if no confirmation (ACCEPT message sent by the client)
   is received by the server before the expiration of the validity time.

9.2.4.  ACCEPT

   The format of ACCEPT message is shown below:

   <ACCEPT Message> ::=  <VERSION>
                         <METHOD_CODE>
                         <SEQUENCE_NUMBER>
                         <TRANSACTION_ID>
                         <CUSTOMER_AGREEMENT_IDENTIFIER>
                         <PROVIDER_AGREEMENT_IDENTIFIER>
                         <NONCE>
                         <AGREED_CONNECTIVITY_PROVISIONING_DOCUMENT>
                         [<INFORMATION_ELEMENT>...]

   This message is used by a client to confirm the acceptance of an
   offer received from a server.  The fields of this message are copied
   from the received OFFER message.

9.2.5.  ACK

   The format of ACK message is shown below:

   <ACK Message> ::=  <VERSION>
                    <METHOD_CODE>
                    <SEQUENCE_NUMBER>
                    <TRANSACTION_ID>
                    <CUSTOMER_AGREEMENT_IDENTIFIER>
                    <PROVIDER_AGREEMENT_IDENTIFIER>

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                    [<EXPECTED_RESPONSE_TIME>]
                    [<CONNECTIVITY_PROVISIONING_DOCUMENT>]
                    [<INFORMATION_ELEMENT>...]

   This message is issued by the server to close a CPNP transaction or
   by a client to grant more negotiation time to the server.

   This message is sent by the server as a response to an ACCEPT,
   WITHDRAW, DECLINE, or CANCEL message.  In such case, the ACK message
   must include the copy of the Connectivity Provisioning Document as
   stored by the server, in particular:

   o  A copy of the requested/offered CPD is included by the server if
      it successfully handled a CANCEL message.
   o  A copy of the updated CPD is included by the server if it
      successfully handled an UPDATE message.
   o  A copy of the offered CPD is included by the server if it
      successfully handled an ACCEPT message in the context of a
      QUOTATION transaction.
   o  An empty CPD is included by the server if it successfully handled
      a DECLINE message.

   A client may issue an ACK message as a response to a more time
   request (conveyed in PROCESSING) received from the server.  In such
   case, the ACK message must include an EXPECTED_RESPONSE_TIME that is
   likely to be set to the time extension requested by the server.

9.2.6.  DECLINE

   The format of DECLINE message is shown below:

   <DECLINE Message> ::=  <VERSION>
                        <METHOD_CODE>
                        <SEQUENCE_NUMBER>
                        <TRANSACTION_ID>
                        <CUSTOMER_AGREEMENT_IDENTIFIER>
                        <PROVIDER_AGREEMENT_IDENTIFIER>
                        <NONCE>

   The client can issue a DECLINE message to reject an offer.
   CUSTOMER_AGREEMENT_IDENTIFIER, PROVIDER_AGREEMENT_IDENTIFIER,
   TRANSACTION_ID, and NONCE are used by the server as keys to find the
   corresponding order.  If an order matches, the server changes the
   state of this order to "Cancelled" and then returns an ACK with a
   copy of the requested CPD to the requesting client.

   If no order is found, the server returns a FAIL message to the
   requesting client.

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   A flow example is shown in Figure 10.

   +------+                              +------+
   |Client|                              |Server|
   +------+                              +------+
      |======QUOTATION (Requested CPD)=====>|
      |<============PROCESSING==============|
      |<========OFFER (Offered CPD)=========|
      |=============PROCESSING=============>|
      |===============DECLINE==============>|
      |<================ACK=================|

                      Figure 10: DECLINE Flow Example

9.2.7.  CANCEL

   The format of CANCEL message is shown below:

   <CANCEL Message> ::= <VERSION>
                        <METHOD_CODE>
                        <SEQUENCE_NUMBER>
                        <TRANSACTION_ID>
                        <CUSTOMER_AGREEMENT_IDENTIFIER>
                        [<CONNECTIVITY_PROVISIONING_DOCUMENT>]

   The client can issue a CANCEL message at any stage during the CPNP
   negotiation process before an agreement is reached.
   CUSTOMER_AGREEMENT_IDENTIFIER and TRANSACTION_ID are used by the
   server as keys to find the corresponding order.  If a quotation order
   matches, the server changes the state of this quotation order to
   "Cancelled" and then returns an ACK with a copy of the requested CPD
   to the requesting client.

   If no quotation order is found, the server returns a FAIL message to
   the requesting client.

9.2.8.  WITHDRAW

   The format of WITHDRAW message is shown below:

   <WITHDRAW Message> ::= <VERSION>
                          <METHOD_CODE>
                          <SEQUENCE_NUMBER>
                          <TRANSACTION_ID>
                          <CUSTOMER_AGREEMENT_IDENTIFIER>
                          <PROVIDER_AGREEMENT_IDENTIFIER>
                          <NONCE>

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                          [<AGREED_CONNECTIVITY_PROVISIONING_DOCUMENT>]
                          [<INFORMATION_ELEMENT>...]

   This message is used to withdraw an offer already subscribed by the
   Customer.  Figure 11 shows a typical usage of this message.

   +------+                              +------+
   |Client|                              |Server|
   +------+                              +------+
      |===========WITHDRAW (CPD)===========>|
      |<============PROCESSING==============|
      |<==========ACK (Empty CPD)===========|

                     Figure 11: WITHDRAW Flow Example

   The CPNP must include the same CUSTOMER_AGREEMENT_IDENTIFIER,
   PROVIDER_AGREEMENT_IDENTIFIER, and NONCE as those used when creating
   the order.

   Upon receipt of a WITHDRAW message, the server checks whether an
   order matching the request is found.  If an order is found, the state
   of the order is changed to "Cancelled" and an ACK message including
   an Empty CPD is returned to the requesting client.  If no order is
   found, the server returns a FAIL message to the requesting client.

9.2.9.  UPDATE

   The format of UPDATE message is shown below:

   <UPDATE Message> ::= <VERSION>
                        <METHOD_CODE>
                        <SEQUENCE_NUMBER>
                        <TRANSACTION_ID>
                        <CUSTOMER_AGREEMENT_IDENTIFIER>
                        <PROVIDER_AGREEMENT_IDENTIFIER>
                        <NONCE>
                        <EXPECTED_RESPONSE_TIME>
                        <REQUESTED_CONNECTIVITY_PROVISIONING_DOCUMENT>
                        [<INFORMATION_ELEMENT>...]

   This message is sent by the CPNP client to update an existing
   connectivity provisioning agreement.  The CPNP must include the same
   CUSTOMER_AGREEMENT_IDENTIFIER, PROVIDER_AGREEMENT_IDENTIFIER, and
   NONCE as those used when creating the order.  The CPNP client
   includes a new CPD which integrates the requested modifications.  A
   new Transaction_ID must be assigned by the client.

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   Upon receipt of an UPDATE message, the server checks whether an
   order, having state "Completed", matches
   CUSTOMER_AGREEMENT_IDENTIFIER, PROVIDER_AGREEMENT_IDENTIFIER, and
   NONCE.

   o  If no order is found, the CPNP server generates a FAIL error with
      the appropriate error code.
   o  If an order is found, the server checks whether it can honor the
      request:

      *  A FAIL message is sent to the client if the server cannot honor
         the request.  The client may initiate a new PQO negotiation
         cycle.
      *  An OFFER message including the updated connectivity
         provisioning document is sent to the client.  For example, the
         server maintains an order for provisioning a VPN service that
         connects sites A, B and C.  If the client sends an UPDATE
         message to remove site C, only sites A and B will be included
         in the OFFER sent by the server to the requesting client.

   A flow chart that illustrates the use of UPDATE operation is shown in
   Figure 12.

   +------+                              +------+
   |Client|                              |Server|
   +------+                              +------+
      |========UPDATE (Requested CPD)======>|
      |<============PROCESSING==============|
      |<========OFFER (Updated CPD)=========|
      |=============PROCESSING=============>|
      |=========ACCEPT (Updated CPD)=======>|
      |<=========ACK (Updated CPD)==========|

                      Figure 12: UPDATE Flow Example

9.2.10.  FAIL

   The format of FAIL message is shown below:

   <FAIL Message> ::= <VERSION>
                      <METHOD_CODE>
                      <SEQUENCE_NUMBER>
                      <TRANSACTION_ID>
                      <CUSTOMER_AGREEMENT_IDENTIFIER>
                      <PROVIDER_AGREEMENT_IDENTIFIER>
                      <STATUS_CODE>

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   This message is sent in the following cases:

   o  The server can not honor an order received from the client (i.e.,
      received in a QUOTATION or UPDATE request).
   o  The server encounters an error when processing a CPNP request
      received from the client.
   o  The client can not grant more time to a the server.  This is a
      response to a more time request conveyed in a PROCESSING message.

   The status code indicates the error code.  The following codes are
   currently supported; other codes will be defined in future versions
   of the document:

   1  (Validation Error): The message can not be validated (see
      Section 10).
   2  (Authentication Required): the request cannot be handled because
      authentication is required.
   3  (Authorization Required): the request cannot be handled because
      authorization failed.
   4  (Administratively prohibited): the request can not be handled
      because of administrative policies.
   5  (Out of Resources): the request can not be honored because there
      is not enough capacity.
   6  (Network Presence): the request can not be honored because there
      is no network presence.
   7  (More Time Rejected): the request to extend the time negotiation
      is rejected by the client.

10.  Message Validation

   Both client and server proceed with CPNP message validation.  The
   following tables summarize the validation checks to be followed.

10.1.  On the Client Side

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   Operation    Validation Checks
   ------------ --------------------------------------------------------
   PROCESSING   {Source IP address, source port, destination IP address,
                destination port, Transaction-ID, Customer Order
                Identifier} must match an existing PQO with a state set
                to "PQOSent". The sequence number carried in the packet
                must be larger than the sequence number maintained by
                the client.
   OFFER        {Source IP address, source port, destination IP address,
                destination port, Transaction-ID, Customer Order
                Identifier} must match an existing order with state set
                to "PQOSent" or {Source IP address, source port,
                destination IP address, destination port, Transaction-
                ID, Customer Order Identifier, Provider Order
                Identifier} must match an existing order with a state
                set to "ServerProcessing". The sequence number carried
                in the packet must be larger than the sequence number
                maintained by the client.
   ACK          {Source IP address, source port, destination IP address,
   (QUOTATION   destination port, Transaction-ID, Customer Order
   Transaction) Identifier, Provider Order Identifier, Offered
                Connectivity Provisioning Order} must match an order
                with a state set to "AcceptSent". The sequence number
                carried in the packet must be larger than the sequence
                number maintained by the client.
   ACK (UPDATE  {Source IP address, source port, destination IP address,
   Transaction) destination port, Transaction-ID, Customer Order
                Identifier, Provider Order Identifier, Updated
                Connectivity Provisioning Order} must match an order
                with a state set to "AcceptSent". The sequence number
                carried in the packet must be larger than the sequence
                number maintained by the client.
   ACK          {Source IP address, source port, destination IP address,
   (WITHDRAW    destination port, Transaction-ID, Customer Order
   Transaction) Identifier, Provider Order Identifier, Empty
                Connectivity Provisioning Order} must match an order
                with a state set to "Cancelled". The sequence number
                carried in the packet must be larger than the sequence
                number maintained by the client.

10.2.  On the Server Side

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   Method     Validation Checks
   ---------- ----------------------------------------------------------
   QUOTATION  The source IP address passes existing access filters (if
              any).  The sequence number carried in the packet must not
              be less than the sequence number maintained by the server.
   PROCESSING The sequence number carried in the packet must be larger
              than the sequence number maintained by the server.
   ACCEPT     {Source IP address, source port, destination IP address,
              destination port, Transaction-ID, Customer Order
              Identifier, Provider Order Identifier, Nonce, Offered
              Connectivity Provisioning Order} must match an order with
              state set to "OfferProposed" or "ProcessngReceived". The
              sequence number carried in the packet must be larger than
              the sequence number maintained by the server.
   DECLINE    {Source IP address, source port, destination IP address,
              destination port, Transaction-ID, Customer Order
              Identifier, Provider Order Identifier, Nonce} must match
              an order with state set to "OfferProposed" or
              "ProcessngReceived". The sequence number carried in the
              packet must be larger than the sequence number maintained
              by the server.
   UPDATE     The source IP address passes existing access filters (if
              any) and {Customer Order Identifier, Provider Order
              Identifier, Nonce} must match an existing order with state
              "Completed".
   WITHDRAW   The source IP address passes existing access filters (if
              any) and {Customer Order Identifier, Provider Order
              Identifier, Nonce} must match an existing order with state
              "Completed".

11.  Theory of Operation

   Both CPNP client and server proceeds to message validation checks as
   specified in Section 10.

11.1.  Client Behavior

11.1.1.  Order Negotiation Cycle

   To place a provisioning quotation order, the client initiates first a
   local quotation order object identified by a unique identifier
   assigned by the client.  The state of the quotation order is set to
   "Created".  The client then generates a QUOTATION request which
   includes the assigned identifier, possibly an expected response time,
   a Transaction-ID and a Requested Connectivity Provisioning Document.
   The client may include additional Information Elements such as
   Negotiation Options.

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   The client may be configured to not enforce negotiation checks on
   EXPECTED_OFFER_TIME; if so no EXPECTED_RESPONSE_TIME attribute (or
   EXPECTED_RESPONSE_TIME set to infinite) should be included in the
   quotation order.

   Once the request is sent to the server, the state of the request is
   set to "PQOSent" and a timer, if a response time is included in the
   quotation order, is set to the expiration time as included in the
   QUOTATION request.  The client also maintains a copy of the extended
   transport session details used to generate the QUOTATION request.
   The CPNP client must listen on the same port number that it used to
   send the QUOTATION request.

   If no answer is received from the server before the retransmission
   timer expires (i.e., RETRANS_TIMER, Section 8.12), the client
   proceeds to retransmission until maximum retry is reached (i.e., 3
   times).  The same sequence number is used for retransmitted packets.

   If a FAIL message is received, the client may decide to issue another
   (corrected) request towards the same server, cancel the local order,
   or contact another server.  The behavior of the client depends on the
   error code returned by the server in the FAIL message.

   If a PROCESSING message matching the CPNP transport session is
   received, the client updates the CPNP session with the
   PROVIDER_AGREEMENT_IDENTIFIER information.  If the client does not
   accept the expected offer time that may have been indicated in the
   PROCESSING message, the client may decide to cancel the quotation
   order.  If the client accepts the EXPECTED_OFFER_TIME, it changes the
   state of the order to "ServerProcessing" and sets a timer to the
   value of EXPECTED_OFFER_TIME.  If no offer is made before the timer
   expires, the client changes the state of the order to "Cancelled".

   As a response to a more time request (conveyed in a PROCESSING
   message that included a new EXPECTED_OFFER_TIME), the client may
   grant this extension by issuing an ACK message or reject the time
   extension with a FAIL message having a status code set to "More Time
   Rejected".

   If an OFFER message matching the extended CPNP session is received,
   the client checks if a PROCESSING message having the same
   PROVIDER_AGREEMENT_IDENTIFIER has been received from the server.  If
   a PROCESSING message was already received for the same order but the
   PROVIDER_AGREEMENT_IDENTIFIER does not match the identifier included
   in the OFFER message, the client ignores silently the message.  If a
   PROCESSING message having the same PROVIDER_AGREEMENT_IDENTIFIER was
   already received and matches the CPNP transaction identifier, the
   client changes the state of the order to "OfferReceived" and sets a

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   timer to the value of VALIDITY_OFFER_TIME indicated in the OFFER
   message.

   If an offer is received from the server (i.e., as documented in an
   OFFER message), the client may accept or reject the offer.  The
   client accepts the offer by generating an ACCEPT message which
   confirms that the client agrees to subscribe to the offer documented
   in the OFFER message; the state of the order is passed to
   "AcceptSent".  The transaction is terminated if an ACK message is
   received from the server.  If no ACK is received from the server, the
   client proceeds with the re-transmission of the ACCEPT message.

   The client may also decide to reject the offer by sending a DECLINE
   message.  The state of the order is set by the client to "Cancelled".
   If an offer is not acceptable by the client, the client may decide to
   contact a new server or submit another order to the same server.
   Guidelines to issue an updated order or terminate the negotiation are
   specific to the client.

11.1.2.  Order Withdrawal Cycle

   A client may withdraw a completed order.  This is achieved by issuing
   a WITHDRAW message.  This message must include Customer Order
   Identifier, Provider Identifier and Nonce returned during the order
   negotiation cycle specified in Section 11.1.1.

   If no ACK is received from the server, the client proceeds with the
   re-transmission of the message.

11.1.3.  Order Update Cycle

   A client may update a completed order.  This is achieved by issuing
   an UPDATE message.  This message must include Customer Order
   Identifier, Provider Order Identifier and Nonce returned during the
   order negotiation cycle specified in Section 11.1.1.  The client must
   include in the UPDATE message an updated CPD with the requested
   changes.

   Subsequent messages exchange is similar to what is documented in
   Section 11.1.1.

11.2.  Server Behavior

11.2.1.  Order Processing

   Upon receipt of a QUOTATION message from a client, the server sets a
   CPNP session, stores Transaction-ID and generates a Provider Order
   Identifier.  Once preliminary validation checks are completed (

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   Section 10), the server may return a PROCESSING message to notify the
   client the quotation order is received and it is under processing;
   the server may include an expected offer time to notify the client by
   when an offer will be proposed.  An order with state
   "AwaitingProcessing" is created by the server.  The server runs its
   decision-making process to decide which offer it can make to honor
   the received order.  The offer should be made before the expected
   offer time expires.

   If the server cannot honor the request, it sends backs a FAIL message
   with the appropriate error code.

   If the server requires more negotiation time, it must send a
   PROCESSING message with a new EXPECTED_OFFER_TIME.  The client may
   grant this extension by issuing an ACK message or reject the time
   extension with a FAIL message having a status code set to "More Time
   Rejected".  If the client doesn't grant more time, the server must
   answer before the initial expected offer time; otherwise the client
   will ignore the quotation order.

   If the server can honor the request, it creates an OFFER message.
   The server must indicate the Transaction-ID, Customer Order
   Identifier as indicated in the QUOTATION message, and the Provider
   Order Identifier generated for this order.  The server must also
   include Nonce and the offered Connectivity Provisioning Document.
   The server includes an offer validity time as well.  Once sent to the
   client, the server changes the state of the order to "OfferSent" and
   a timer set to the validity time is initiated.

   If the server determines that additional network resources from
   another network provider are needed to accommodate a quotation order,
   it will create child PQO(s) and will behave as a CPNP client to
   negotiate child PQO(s) with possible partnering providers (see
   Figure 5).

   If no PROCESSING, ACCEPT or DECLINE message is received before the
   expiry of the RETRANS_TIMER, the server re-sends the same offer to
   the client.  This procedure is repeated until maximum retry is
   reached.

   If an ACCEPT message is received before the offered validity time
   expires, the server proceeds with validation checks as specified in
   Section 10.  The state of the corresponding order is passed to
   "AcceptReceived".  The server sends back an ACK message to terminate
   the order processing cycle.

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   If a CANCEL/DECLINE message is received, the server proceeds with the
   cancellation of the order.  The state of the order is then passed to
   "Cancelled".

11.2.2.  Order Withdrawal

   A client may withdraw a completed order by issuing a WITHDRAW
   message.  Upon receipt of a WITHDRAW message, the server proceeds
   with the validation checks, as specified in Section 10.

   o  If the checks fail, a FAIL message is sent back to the client with
      the appropriate error code.

   o  If the checks succeed, the server clears the clauses of the
      Connectivity Provisioning Document, changes the state of the order
      to "Cancelled", and sends back an ACK message with an Empty
      Connectivity Provisioning Document.

11.2.3.  Order Update

   A client may update an order by issuing an UPDATE message.  Upon
   receipt of an UPDATE message, the server proceeds with the validation
   checks as specified in Section 10.

   o  If the checks fail, a FAIL message is sent back to the client with
      the appropriate error code.
   o  Subsequent messages exchange is similar to what is specified in
      Section 11.1.1.  The server should generate a new Nonce value to
      be included in the offer made to the client.

11.3.  Sequence Numbers

   In each transaction, sequence numbers are used to protect the
   transaction against replay attacks.  Each communicating partner of
   the transaction maintains two sequence numbers, one for incoming
   packets and one for outgoing packets.  When a partner receives a
   message, it will check whether the sequence number in the message is
   larger than the incoming sequence number maintained locally.  If not,
   the messages will be discarded.  If the message is proved to be
   legal, the value of the incoming sequence number will be replaced by
   the value of the sequence number in the message.  When a partner
   sends out a message, it will insert the value of outgoing sequence
   number into the message and increase the outgoing sequence number
   maintained locally by 1.

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11.4.  Message Re-Transmission

   As mentioned above, if a transaction partner sends out a message and
   does not receives any expected reply before the retransmission timer
   expires (i.e., RETRANS_TIMER), a transaction partner will try to re-
   transit the messages.  An exception is the last message (e.g., ACK)
   sent from the server in a transaction.  After sending this message,
   the retransmission timer will be disabled since no additional
   feedback is expected.

   In addition, if the partner receives a re-sent last incoming packet,
   the partner can also send out the answer to the incoming packet with
   a limited frequency.  If no answer was generated at the moment, the
   partner needs to generate a PROCESSING message as the answer.

   To benefit message re-transmission, a partner could also store the
   last incoming packet and the associated answer.  Note that the times
   of re-transmission could be decided by the local policy and re-
   transmission will not cause any change of sequence numbers.

12.  Operational Guidelines

12.1.  Logging on the CPNP Server

   The CPNP server SHOULD be configurable to log various events and
   associated information.  Such information includes:

   o  Client's IP Address
   o  Any event change (e.g., new quotation order, offer sent, order
      confirm, order cancellation, order withdraw, etc.)
   o  Timestamp

12.2.  Business Guidelines & Objectives

   The CPNP server can operate in the following modes:

   1.  Fully automated mode: The CPNP server is provisioned with a set
       of business guidelines and objectives that will be used as an
       input to the decision-making process.  The CPNP server will
       service received orders that falls into these business
       guidelines; otherwise requests will be escalated to an
       administrator that will formally validate/invalidate an order
       request.  The set of policies to be configured to the CPNP server
       are specific to each administrative entity managing a CPNP
       server.

   2.  Administrative-based mode: This mode assumes some or all CPNP
       server' operations are subject to a formal administrative

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       validation.  CPNP events will trigger appropriate validation
       requests that will be forwarded to the contact person(s) or
       department which is responsible for validating the orders.
       Administrative validation messages are relayed using another
       protocol (e.g., SMTP) or a dedicated tool.

   Business guidelines are local to each administrative entity.  How
   validation requests are presented to an administrator are out of
   scope of this document; each administrative entity may decide the
   appropriate mechanism to enable for that purpose.

13.  Security Considerations

   Means to defend the server against denial-of-service attacks must be
   enabled.  For example, access control lists (ACLs) can be enforced on
   the client, the server or the network in between, to allow a trusted
   client to communicate with a trusted server.

   The client and the server should be mutually authenticated.  Out of
   band mechanisms can be used instead of integrating them into CPNP.

   The client must silently discard CPNP responses received from unknown
   CPNP servers.  The use of a randomly generated Transaction-ID makes
   it hard to forge a response from a server with a spoofed IP address
   belonging the legitimate CPNP server.  Furthermore, CPNP messages
   from the server must also include correct identifiers of the orders.
   Two order identifiers are used: one generated by the client and the
   second one is generated by the server.

   The Provider must enforce means to protect privacy-related
   information captured in a CPP documents exchanged using CPNP messages
   [RFC6462].  In particular, this information must not be revealed to
   external parties without the consent of Customers.  Providers should
   enforce policies to make Customer fingerprinting more difficult to
   achieve.  For more discussion about privacy, refer to
   [RFC6462][RFC6973].

   The nonce and the transaction IDs provide sufficient randomness and
   can effectively tolerate the attacks raised by off-line adversaries
   who do not have the capability of eavesdropping and intercepting the
   packets transported between the client and the server.  Only
   authorized clients must be able to modify existing CPNP orders.  The
   use of a randomly generated Nonce by the server makes it hard to
   modify an order on behalf of a third-party.

   In the base CPNP protocol, sequence numbers can be used to detect the
   replay attacks by re-sending the antique packets intercepted from the
   current transaction.  However, the based protocol may be vulnerable

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   to the replay attacks where the replayed packets are intercepted from
   antique transactions.  Although the transaction ID provided by the
   client could protect it from inter-transaction replay attacks, no
   protection is provided for the server to deal with this type of
   attack.

   The base protocol does not provide any security mechanism to protect
   the confidentiality and integrity of the packets transported between
   the client and the server.  An underlying security protocol such as
   (e.g DTLS [RFC6347], IPsec) could be used to protect the integrity or
   confidentiality for the protocol.  In this case, if it is possible to
   provide an AKM and associate each transaction a different key, inter-
   transaction replay attacks can be naturally addressed.  If the client
   and the server use a single key to secure multiple transactions, the
   additional mechanism should be provided against inter-transaction
   replay attacks.  However, how to address this issue is out of scope
   of this document.

14.  IANA Considerations

   Authors of the document request IANA to assign a UDP port for CPNP.

   A registry for CPNP methods should be created.  The following codes
   are reserved:

   1:   QUOTATION
   2:   PROCESSING
   3:   OFFER
   4:   ACCEPT
   5:   DECLINE
   6:   ACK
   7:   CANCEL
   8:   WITHDRAW
   9:   UPDATE
   10:  FAIL

   A registry for CPNP errors should be created.  The following codes
   are reserved:

   1:  Message Validation Error
   2:  Authentication Required
   3:  Authorization Failed
   4:  Administratively prohibited
   5:  Out of Resources
   6:  Network Presence Error
   7:  More Time Rejected

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15.  Acknowledgements

   Thanks to Diego R.  Lopez for his comments.

   Special thanks to Panos Georgatsos for the detailed review.

16.  References

16.1.  Normative References

   [RFC1123]  Braden, R., "Requirements for Internet Hosts - Application
              and Support", STD 3, RFC 1123, October 1989.

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

   [RFC4086]  Eastlake, D., Schiller, J., and S. Crocker, "Randomness
              Requirements for Security", BCP 106, RFC 4086, June 2005.

   [RFC5511]  Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax
              Used to Form Encoding Rules in Various Routing Protocol
              Specifications", RFC 5511, April 2009.

16.2.  Informative References

   [RFC2782]  Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
              specifying the location of services (DNS SRV)", RFC 2782,
              February 2000.

   [RFC4176]  El Mghazli, Y., Nadeau, T., Boucadair, M., Chan, K., and
              A. Gonguet, "Framework for Layer 3 Virtual Private
              Networks (L3VPN) Operations and Management", RFC 4176,
              October 2005.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, January 2012.

   [RFC6462]  Cooper, A., "Report from the Internet Privacy Workshop",
              RFC 6462, January 2012.

   [RFC6770]  Bertrand, G., Stephan, E., Burbridge, T., Eardley, P., Ma,
              K., and G. Watson, "Use Cases for Content Delivery Network
              Interconnection", RFC 6770, November 2012.

   [RFC6973]  Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
              Morris, J., Hansen, M., and R. Smith, "Privacy
              Considerations for Internet Protocols", RFC 6973, July
              2013.

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   [RFC7149]  Boucadair, M. and C. Jacquenet, "Software-Defined
              Networking: A Perspective from within a Service Provider
              Environment", RFC 7149, March 2014.

   [RFC7297]  Boucadair, M., Jacquenet, C., and N. Wang, "IP
              Connectivity Provisioning Profile (CPP)", RFC 7297, July
              2014.

Authors' Addresses

   Mohamed Boucadair
   France Telecom
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com

   Christian Jacquenet
   France Telecom
   Rennes  35000
   France

   Email: christian.jacquenet@orange.com

   Dacheng Zhang
   Huawei Technologies

   Email: zhangdacheng@huawei.com

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