Connectivity Provisioning Negotiation Protocol (CPNP)
draft-boucadair-connectivity-provisioning-protocol-00
Network Working Group M. Boucadair
Internet-Draft C. Jacquenet
Intended status: Standards Track France Telecom
Expires: November 30, 2013 May 29, 2013
Connectivity Provisioning Negotiation Protocol (CPNP)
draft-boucadair-connectivity-provisioning-protocol-00
Abstract
This document specifies the Connectivity Provisioning Negotiation
Protocol (CPNP) which is used to facilitate the dynamic negotiation
of connectivity provisioning parameters between a Customer and a
Provider.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 30, 2013.
Copyright Notice
Copyright (c) 2013 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
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
Boucadair & Jacquenet Expires November 30, 2013 [Page 1]
Internet-Draft CPNP May 2013
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
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. Order Processing Models . . . . . . . . . . . . . . . . . . . 4
4. Functional Elements . . . . . . . . . . . . . . . . . . . . . 5
5. Sample Use Cases . . . . . . . . . . . . . . . . . . . . . . 6
6. Deployment Models . . . . . . . . . . . . . . . . . . . . . . 7
7. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Client/Server Communication . . . . . . . . . . . . . . . 7
7.2. Server Discovery . . . . . . . . . . . . . . . . . . . . 7
7.3. Policy Configuration on the CPNP Server . . . . . . . . . 8
7.4. CPNP Negotiation Model . . . . . . . . . . . . . . . . . 9
7.5. CPNP Session . . . . . . . . . . . . . . . . . . . . . . 10
7.6. Extended CPNP Session . . . . . . . . . . . . . . . . . . 11
7.7. CPNP Transaction . . . . . . . . . . . . . . . . . . . . 11
7.8. CPNP Operations . . . . . . . . . . . . . . . . . . . . . 11
7.9. Connectivity Provisioning Documents . . . . . . . . . . . 12
7.10. Child Connectivity Provisioning Quotation Orders . . . . 13
7.11. State Management . . . . . . . . . . . . . . . . . . . . 14
7.11.1. On The Client Side . . . . . . . . . . . . . . . . . 14
7.11.2. On The Server Side . . . . . . . . . . . . . . . . . 15
7.12. CPNP Timers . . . . . . . . . . . . . . . . . . . . . . . 17
8. CPNP Objects . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1. Attributes . . . . . . . . . . . . . . . . . . . . . . . 17
8.1.1. CUSTOMER_ORDER_IDENTIFIER . . . . . . . . . . . . . . 17
8.1.2. PROVIDER_ORDER_IDENTIFIER . . . . . . . . . . . . . . 18
8.1.3. TRANSACTION_ID . . . . . . . . . . . . . . . . . . . 18
8.1.4. NONCE . . . . . . . . . . . . . . . . . . . . . . . . 18
8.1.5. EXPECTED_RESPONSE_DATE . . . . . . . . . . . . . . . 18
8.1.6. EXPECTED_OFFER_DATE . . . . . . . . . . . . . . . . . 18
8.1.7. VALIDITY_DATE . . . . . . . . . . . . . . . . . . . . 18
8.1.8. CONNECTIVITY_PROVISIONING_DOCUMENT . . . . . . . . . 19
8.1.9. Information Elements . . . . . . . . . . . . . . . . 19
8.2. Operation Messages . . . . . . . . . . . . . . . . . . . 20
8.2.1. PROVISION . . . . . . . . . . . . . . . . . . . . . . 20
8.2.2. PROCESSING . . . . . . . . . . . . . . . . . . . . . 21
8.2.3. OFFER . . . . . . . . . . . . . . . . . . . . . . . . 21
8.2.4. ACCEPT . . . . . . . . . . . . . . . . . . . . . . . 22
8.2.5. ACK . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.2.6. DECLINE . . . . . . . . . . . . . . . . . . . . . . . 23
8.2.7. CANCEL . . . . . . . . . . . . . . . . . . . . . . . 24
Boucadair & Jacquenet Expires November 30, 2013 [Page 2]
Internet-Draft CPNP May 2013
8.2.8. WITHDRAW . . . . . . . . . . . . . . . . . . . . . . 24
8.2.9. UPDATE . . . . . . . . . . . . . . . . . . . . . . . 25
8.2.10. FAIL . . . . . . . . . . . . . . . . . . . . . . . . 26
9. Message Validation . . . . . . . . . . . . . . . . . . . . . 27
9.1. On The Client Side . . . . . . . . . . . . . . . . . . . 27
9.2. On The Server Side . . . . . . . . . . . . . . . . . . . 27
10. Theory of Operations . . . . . . . . . . . . . . . . . . . . 28
10.1. Client Behavior . . . . . . . . . . . . . . . . . . . . 28
10.1.1. Order Negotiation Cycle . . . . . . . . . . . . . . 28
10.1.2. Order Withdrawal Cycle . . . . . . . . . . . . . . . 30
10.1.3. Order Update Cycle . . . . . . . . . . . . . . . . . 30
10.2. Server Behavior . . . . . . . . . . . . . . . . . . . . 30
10.2.1. Order Processing . . . . . . . . . . . . . . . . . . 30
10.2.2. Order Withdrawal . . . . . . . . . . . . . . . . . . 31
10.2.3. Order Update . . . . . . . . . . . . . . . . . . . . 32
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32
12. Security Considerations . . . . . . . . . . . . . . . . . . . 32
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 33
13.1. Normative References . . . . . . . . . . . . . . . . . . 33
13.2. Informative References . . . . . . . . . . . . . . . . . 33
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34
1. Introduction
[I-D.boucadair-connectivity-provisioning-profile] describes a
Connectivity Provisioning Profile (CPP) template to capture
connectivity requirements to be met by a transport infrastructure for
the delivery of services (e.g., Voice over IP, IPTV, VPN services).
The CPP profile defines the set of IP transfer guarantees to be
offered by the underlying transport network together with a
reachability scope and capacity needs.
This document defines the Connectivity Provisioning Negotiation
Protocol (CPNP) that is meant to dynamically exchange and negotiate
the connectivity provisioning 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. CPNP can be seen as a component of the
dynamic negotiation meta-domain described in Section 3.4 of
[I-D.sin-sdnrg-sdn-approach].
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.
Boucadair & Jacquenet Expires November 30, 2013 [Page 3]
Internet-Draft CPNP May 2013
2. Terminology
This document makes use of the following terms:
o Customer: is a business role which denotes an entity that is
involved in the definition and the possible negotiation of a
Connectivity Provisioning Agreement with a Network Provider. This
contract is captured in a dedicated CPP (Connectivity Provisioning
Profile, [I-D.boucadair-connectivity-provisioning-profile])
template, which specifies (among other information): the sites to
be connected, border nodes, outsourced operations (e.g., routing).
The right to invoke the connectivity 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.
3. Order Processing Models
There are basically two models for customer's order processing
purposes:
1. Frozen model: The Customer cannot negotiate the parameters of the
connectivity 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. 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
Boucadair & Jacquenet Expires November 30, 2013 [Page 4]
Internet-Draft CPNP May 2013
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.
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.
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.
4. Functional Elements
The following functional elements are defined in the context of CPNP:
o 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 connectivity provisioning quotation order.
2. Cancel an ongoing connectivity provisioning quotation order
under negotiation.
3. Withdraw a pre-negotiated connectivity provisioning order.
Boucadair & Jacquenet Expires November 30, 2013 [Page 5]
Internet-Draft CPNP May 2013
4. Update a pre-negotiated connectivity provisioning order.
o 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. Network provision quotation order handling.
2. Cancel an ongoing connectivity provisioning quotation order.
3. Handling of a connectivity provisioning order withdrawal.
5. Sample Use Cases
A list of CPNP use cases is provided below:
o [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].
o 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.
o 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.
o Service Providers can initiate connectivity provisioning requests
towards Network Providers using CPNP. Multiple CPNP ordering
cycles can be initiated by a Service Provider towards multiple
Network Providers. Only a subset of these orders may be put into
effect.
Boucadair & Jacquenet Expires November 30, 2013 [Page 6]
Internet-Draft CPNP May 2013
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
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. Protocol Overview
7.1. 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 11) 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 messages can also be transported over DTLS [RFC6347].
7.2. Server Discovery
Boucadair & Jacquenet Expires November 30, 2013 [Page 7]
Internet-Draft CPNP May 2013
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.
7.3. Policy Configuration on the CPNP Server
As an input to the CPNP server's decision-making process, the CPNP
server is 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 1).
+-------------------------------------------------------+
| Administrative Blocks (e.g., 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 1: 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 connectivity
provisioning quotation request.
Boucadair & Jacquenet Expires November 30, 2013 [Page 8]
Internet-Draft CPNP May 2013
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
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.
7.4. CPNP Negotiation Model
CPNP adopts a Quotation Order/Offer/Answer model where:
1. The client specifies its requirements via a connectivity
provisioning quotation order (CPQO).
2. The server makes an offer to either address the requirements of
the CPQO or suggests a counter-proposal that partially addresses
the requirements of the CPQO or declines the CPQO.
3. The client either accepts or declines the offer.
Boucadair & Jacquenet Expires November 30, 2013 [Page 9]
Internet-Draft CPNP May 2013
Only one Offer/Answer stage is assumed within one single CPNP
transaction (Section 7.7). Nevertheless, multiple CPNP transactions
can be undertaken by the CPNP client (see Figure 2).
+------+ +------+ +------+ +------+
|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(CPDa)==>| |==Quotation Order(CPD1)==>|
|<====Make an offer========| |<=====Make an offer=======|
|========Decline==========>| |=========Decline=========>|
|==Quotation Order(CPDb)==>| |==Quotation Order(CPD2)==>|
|<====Make an offer========| |<=====Make an offer=======|
|=========Accept==========>| |=========Decline=========>|
|==Quotation Order(CPD3)==>|
|<=====Make an offer=======|
|=========Decline=========>|
|==Quotation Order(CPD4)==>|
|<==Fail to make an offer==|
N-Step Negotiation Cycle: N-Step Negotiation Cycle:
Successful Negotiation Failed Negotiation
Figure 2: Overall Negotiation Process
7.5. CPNP Session
Both the client and servers maintains 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
Boucadair & Jacquenet Expires November 30, 2013 [Page 10]
Internet-Draft CPNP May 2013
7.6. Extended CPNP Session
An extended CPNO session denotes a 4-uplet defined as follows
o CPNP session
o Customer Order Identifier
o Provider Order Identifier
o Transaction-ID
7.7. 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, 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.
Using cryptographically random Transaction-IDs provides some
protection against session hijacking.
7.8. 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 PROVISION: This operation is used to initiate a connectivity
provisioning quotation order. Upon receipt of a PROVISION
request, the server may response with a PROCESSING, OFFER or a
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.
Boucadair & Jacquenet Expires November 30, 2013 [Page 11]
Internet-Draft CPNP May 2013
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 PROVISION message.
o ACCEPT: This operation is used to confirm the acceptance of an
offer made by the server.
o ACK: This operation is used by the server to acknowledge the
receipt of an ACCEPT or WITHDRAW message.
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
connectivity provisioning quotation order.
o WITHDRAW: This operation is used by the client to withdraw a pre-
negotiated connectivity provisioning order.
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 CPQO conveyed in
the PROVISION message. This operation can also be used by a
server to inform the client about an error encountered when
processing the received message. The message includes the status
code which provides more information about the error.
7.9. Connectivity Provisioning Documents
CPNP makes use of several flavors of Connectivity Provisioning
Documents (CPD). All these documents follow the CPP template
described in [I-D.boucadair-connectivity-provisioning-profile].
o Requested Connectivity Provisioning Document: refers to the CPD
included by a CPNP client in a PROVISION 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 date is associated
with the offer.
Boucadair & Jacquenet Expires November 30, 2013 [Page 12]
Internet-Draft CPNP May 2013
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 3 shows a typical CPNP transaction and the use of Connectivity
Provisioning Documents:
+------+ +------+
|Client| |Server|
+------+ +------+
|======PROVISION (Requested CPD)=====>|
|<============PROCESSING==============|
|<========OFFER (Offered CPD)=========|
|=============PROCESSING=============>|
|=========ACCEPT (Agreed CPD)========>|
|<=========ACK (Agreed CPD)===========|
Figure 3: Connectivity Provisioning Documents
7.10. Child Connectivity 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 CPQO (e.g., context of an inter-domain VPN service
where additional PE router resources need to be allocated), the
server may generate child CPQOs to request the appropriate network
provisioning operations (see Figure 4). In such situation, the
server behaves as a CPNP client. The server must also associate the
parent order with its child CPQOs. This is typically achieved by
locally adding the reference of the child CPQO to the parent order.
+------+ +--------+ +--------+
|Client| |Server A| |Server B|
+------+ +--------+ +--------+
| | |
|=====PROVISION=====>| |
|<====PROCESSING=====| |
| |=====PROVISION=====>|
| |<====PROCESSING=====|
| |<=======OFFER=======|
| |=====PROCESSING====>|
| |=======ACCEPT======>|
| |<=======ACK=========|
|<=======OFFER=======| |
|<====PROCESSING=====| |
|=======ACCEPT======>| |
|<=======ACK=========| |
Boucadair & Jacquenet Expires November 30, 2013 [Page 13]
Internet-Draft CPNP May 2013
Figure 4: Example of Child Orders
7.11. State Management
Both the client and the server maintain repositories to store ongoing
orders. Contracted orders can be stored in the same repositories or
be stored in a dedicated one (e.g., Connectivity Provisioning
Agreements). Timestamps are also logged for any state change.
7.11.1. 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.
o CPQOSent: when the CPQO 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.
+------------------+
| Created |-----------------+
+------------------+ |
| |
v |
+------------------+ |
|AwaitingProcessing|----------------+|
+------------------+ ||
| ||
PROVISION ||
v ||
+------------------+ ||
| CPQOSent |---CANCEL------+||
+------------------+ vvv
| +-----+
PROCESSING | |
v | |
+------------------+ CANCEL | C |
| ServerProcessing |------------>| A |
+------------------+ FAIL | N |
Boucadair & Jacquenet Expires November 30, 2013 [Page 14]
Internet-Draft CPNP May 2013
| | C |
| | E |
OFFER | L |
| | L |
v | E |
+------------------+ | D |
| OfferReceived |---CANCEL--->| |
+------------------+ | |
| PROCESSING +-----+
v ^^^
+------------------+ |||
| OfferProcessing |---DECLINE-----+||
+------------------+ ||
| ACCEPT ||
v ||
+------------------+ ||
| AcceptSent |---CANCEL-------+|
+------------------+ |
| ACK |
v |
+------------------+ |
| AcceptAck |---WITHDRAW------+
+------------------+
Figure 5: CPNP Finite State Machine (Client Side)
7.11.2. On The Server Side
The following lists the states which can be associated with a given
order on the server's side:
o CPQOReceived: when the connectivity 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 CPQO has been created because resources
from another network provider are needed.
Boucadair & Jacquenet Expires November 30, 2013 [Page 15]
Internet-Draft CPNP May 2013
o ChildCPQOSent: when a child CPQO has been sent to another server.
o ChildServerProcessing: when a child CPQO is currently processed by
another server.
o ChildOfferReceived: when an offer has been received to a child
CPQO.
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.
+------------------+
+---------------------| ChildCreated |
| +------------------+
v | ^
+------------------+ | |
| ChildCPQOSent |----------------+| P
+------------------+ || R
| || O
PROVISION || V
v || I +--------------------+
+---------------------+ CANCEL || S | CPQOReceived |
|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
Boucadair & Jacquenet Expires November 30, 2013 [Page 16]
Internet-Draft CPNP May 2013
+------------------+ ||| | +------------------+
| ChildAcceptSent |---CANCEL------+|+-WITHDRAW|-| AcceptAck |
+------------------+ | | +------------------+
| ACK | |
v | |
+------------------+ | |
| ChildAcceptAck |---WITHDRAW-----+ |
+------------------+ |
| |
+--------------------------------------+
Figure 6: CPNP Finite State Machine (Server Side)
7.12. 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 10.
The response timer (RESPONSE_TIMER) is the maximum time, defined in
seconds, between a connectivity provisioning quotation order request
sent to the server and the corresponding response. If this timer is
exceeded, the corresponding connectivity provisioning 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.
8. CPNP Objects
This section defines CPNP objects using the RBNF format defined at
[RFC5511].
8.1. Attributes
8.1.1. CUSTOMER_ORDER_IDENTIFIER
CUSTOMER_ORDER_IDENTIFIER is an identifier which is assigned by a
client to identify an order. This identifier must be unique. Rules
for assigning this identifier are specific to the client. The value
of CUSTOMER_ORDER_IDENTIFIER is included in all CPNP messages.
The server handles CUSTOMER_ORDER_IDENTIFIER as an opaque value.
Boucadair & Jacquenet Expires November 30, 2013 [Page 17]
Internet-Draft CPNP May 2013
8.1.2. PROVIDER_ORDER_IDENTIFIER
PROVIDER_ORDER_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_ORDER_IDENTIFIER is included in all
CPNP message, except PROVISION messages.
The client handles PROVIDER_ORDER_IDENTIFIER as an opaque value.
8.1.3. TRANSACTION_ID
This object conveys the Transaction-ID introduced in Section 7.7.
8.1.4. NONCE
NONCE is a random value assigned by the CPNP server. It is
RECOMMENDED to assign unique NONCE values for each order.
NONCE is mandatory to be included in subsequent CPNP client
operations such as: withdraw an existing order or update an order.
If the NONCE validation checks fail, the server rejects the request
with a FAIL message including the appropriate failure reason code.
8.1.5. EXPECTED_RESPONSE_DATE
This attribute indicates the date by when the client is expecting to
receive a response from the server. If no offer is received by then,
the client will consider the quotation order as rejected.
EXPECTED_RESPONSE_DATE follows date format specified in [RFC1123].
8.1.6. EXPECTED_OFFER_DATE
This attribute indicates the date 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.
EXPECTED_OFFER_DATE follows date format specified in [RFC1123].
8.1.7. VALIDITY_DATE
This attribute indicates the date of a 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.
Boucadair & Jacquenet Expires November 30, 2013 [Page 18]
Internet-Draft CPNP May 2013
VALIDITY_DATE follows date format specified in [RFC1123].
8.1.8. 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>
8.1.9. Information Elements
An Information Element is an optional object which can be included in
a CPNP message.
8.1.9.1. Customer Description
The client may include administrative information such as:
o Name
o Contact Information
The format of this Information Element is as follows:
Boucadair & Jacquenet Expires November 30, 2013 [Page 19]
Internet-Draft CPNP May 2013
<Customer Description> ::= <NAME> <Contact Information>
<Contact Information> ::= <EMAIL_ADDRESS> [<POSTAL_ADDRESS>]
[<TELEPHONE_NUMBER> ...]
8.1.9.2. 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>]
8.1.9.3. 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>]
8.2. Operation Messages
This section specifies the RBNF format of CPNP operation messages.
8.2.1. PROVISION
The format of PROVISION message is shown below:
<PROVISION Message> ::= <VERSION>
<METHOD_CODE>
Boucadair & Jacquenet Expires November 30, 2013 [Page 20]
Internet-Draft CPNP May 2013
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
[<EXPECTED_RESPONSE_DATE>]
<CONNECTIVITY_PROVISIONING_DOCUMENT>
[<INFORMATION_ELEMENT>...]
A PROVISION message must include an order identifier which is
generated by the client. Because several orders can be issued to
several servers, the PROVISION message must also include a
Transaction-ID. The message may include an EXPECTED_RESPONSE_DATE
which indicates by when the client is expecting to receive an offer
from the server. PROVISION message must also include a requested
connectivity provisioning document.
When the client sends the PROVISION message to the server, the state
of the order changes to "CPQOSent".
8.2.2. PROCESSING
The format of PROCESSING Message is shown below:
<PROCESSING Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
[<EXPECTED_OFFER_DATE>]
Upon receipt of a PROVISION message, the server proceeds with parsing
rules (see Section 9). If no error is encountered, the server
generates a PROCESSING response to the client to indicate the CPQO
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
CUSTOMER_ORDER_IDENTIFIER and TRANSACTION_ID fields as conveyed in
the PROVISION message. The server may include an EXPECTED_OFFER_DATE
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 CPQO to that server and which contains the
CUSTOMER_ORDER_IDENTIFIER and TRANSACTION_ID. If no such CPQO is
found, the PROCESSING message is silently ignored. If a CPQO is
found, the client may check if it accepts the EXPECTED_OFFER_DATE and
then, it changes to state of the order to "ServerProcessing".
8.2.3. OFFER
The format of OFFER message is shown below:
Boucadair & Jacquenet Expires November 30, 2013 [Page 21]
Internet-Draft CPNP May 2013
<OFFER Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
<NONCE>
<VALIDITY_DATE>
<CONNECTIVITY_PROVISIONING_DOCUMENT>
[<INFORMATION_ELEMENT>...]
The server answers with an OFFER message to a PROVISION 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 date.
8.2.4. ACCEPT
The format of ACCEPT message is shown below:
<ACCEPT Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
<NONCE>
<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.
8.2.5. ACK
The format of ACK message is shown below:
<ACK Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
<CONNECTIVITY_PROVISIONING_DOCUMENT>
[<INFORMATION_ELEMENT>...]
Boucadair & Jacquenet Expires November 30, 2013 [Page 22]
Internet-Draft CPNP May 2013
This message is issued by the server to close a CPNP transaction. In
particular, this message is sent as a response to an ACCEPT,
WITHDRAW, DECLINE, or CANCEL message. 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
PROVISION transaction.
o An empty CPD is included by the server if it successfully handled
a DECLINE message.
8.2.6. DECLINE
The format of DECLINE message is shown below:
<DECLINE Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
The client can issue a DECLINE message to reject an offer.
CUSTOMER_ORDER_IDENTIFIER, PROVIDER_ORDER_IDENTIFIER and
TRANSACTION_ID 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.
A flow example is shown in Figure 7.
+------+ +------+
|Client| |Server|
+------+ +------+
|======PROVISION (Requested CPD)=====>|
|<============PROCESSING==============|
|<========OFFER (Offered CPD)=========|
|=============PROCESSING=============>|
|===============DECLINE==============>|
|<================ACK=================|
Boucadair & Jacquenet Expires November 30, 2013 [Page 23]
Internet-Draft CPNP May 2013
Figure 7: DECLINE Flow Example
8.2.7. CANCEL
The format of CANCEL message is shown below:
<CANCEL Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
[<CONNECTIVITY_PROVISIONING_DOCUMENT>]
The client can issue a CANCEL message at any stage during the CPNP
negotiation process. CUSTOMER_ORDER_IDENTIFIER and TRANSACTION_ID
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.
8.2.8. WITHDRAW
The format of WITHDRAW message is shown below:
<WITHDRAW Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
<NONCE>
[<CONNECTIVITY_PROVISIONING_DOCUMENT>]
[<INFORMATION_ELEMENT>...]
This message is used to withdraw an offer already subscribed by the
Customer. Figure 8 shows a typical usage of this message.
+------+ +------+
|Client| |Server|
+------+ +------+
|===========WITHDRAW (CPD)===========>|
|<============PROCESSING==============|
|<==========ACK (Empty CPD)===========|
Figure 8: WITHDRAW Flow Example
Boucadair & Jacquenet Expires November 30, 2013 [Page 24]
Internet-Draft CPNP May 2013
The CPNP must include the same CUSTOMER_ORDER_IDENTIFIER,
PROVIDER_ORDER_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.
8.2.9. UPDATE
The format of UPDATE message is shown below:
<UPDATE Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
<NONCE>
<EXPECTED_RESPONSE_DATE>
<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_ORDER_IDENTIFIER, PROVIDER_ORDER_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.
Upon receipt of an UPDATE message, the server checks whether an
order, having state "Completed", matches CUSTOMER_ORDER_IDENTIFIER,
PROVIDER_ORDER_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 CPQO negotiation
cycle.
Boucadair & Jacquenet Expires November 30, 2013 [Page 25]
Internet-Draft CPNP May 2013
* 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 9.
+------+ +------+
|Client| |Server|
+------+ +------+
|=========UPDATE (Diff CPD)==========>|
|<============PROCESSING==============|
|<========OFFER (Updated CPD)=========|
|=========ACCEPT (Updated CPD)=======>|
|<=========ACK (Updated CPD)==========|
Figure 9: UPDATE Flow Example
8.2.10. FAIL
The format of FAIL message is shown below:
<FAIL Message> ::= <VERSION>
<METHOD_CODE>
<TRANSACTION_ID>
<CUSTOMER_ORDER_IDENTIFIER>
<PROVIDER_ORDER_IDENTIFIER>
<STATUS_CODE>
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 PROVISION or UPDATE request).
o The server encounters an error when processing a CPNP request
received from the client.
The status code indicates the error code. The following codes are
currently supported; other codes will be defined in future versions
of the document:
o 1 (Validation Error): The message can not be validated (see
Section 9).
o 2 (Authentication Required): the request cannot be handled because
authentication is required.
Boucadair & Jacquenet Expires November 30, 2013 [Page 26]
Internet-Draft CPNP May 2013
o 3 (Administratively prohibited): the request can not be handled
because of administrative policies.
o 4 (Out of Resources): the request can not be honored because there
is not enough capacity.
o 5 (Network Presence): the request can not be honored because there
is no network presence.
9. Message Validation
Both client and server proceed with CPNP message validation. The
following tables summarize the validation checks to be followed.
9.1. On The Client Side
Operation Validation Checks
--------------- -----------------------------------------------------
PROCESSING {Source IP address, source port, destination IP
address, destination port, Transaction-ID, Customer
Order Identifier} must match an existing CPQO with a
state set to "CPQOSent".
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 "CPQOSent" 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".
ACK (PROVISION {Source IP address, source port, destination IP
Transaction) address, destination port, Transaction-ID, Customer
Order Identifier, Provider Order Identifier, Offered
Connectivity Provisioning Order} must match an order
with a state set to "AcceptSent".
ACK (UPDATE {Source IP address, source port, destination IP
Transaction) address, destination port, Transaction-ID, Customer
Order Identifier, Provider Order Identifier, Updated
Connectivity Provisioning Order} must match an order
with a state set to "AcceptSent".
ACK (WITHDRAW {Source IP address, source port, destination IP
Transaction) address, destination port, Transaction-ID, Customer
Order Identifier, Provider Order Identifier, Empty
Connectivity Provisioning Order} must match an order
with a state set to "Cancelled".
9.2. On The Server Side
Boucadair & Jacquenet Expires November 30, 2013 [Page 27]
Internet-Draft CPNP May 2013
Method Validation Checks
----------- ---------------------------------------------------------
PROVISION The source IP address passes existing access filters (if
any).
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".
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".
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".
10. Theory of Operations
Both CPNP client and server proceeds to message validation checks as
specified in Section 9.
10.1. Client Behavior
10.1.1. Order Negotiation Cycle
To place a connectivity provisioning quotation order, the client
initiates first a local 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 PROVISION request
which includes the assigned identifier, possibly an Expected Response
Date, a Transaction-ID and a Requested Connectivity Provisioning
Document. The client may include additional Information Elements
such as Negotiation Options.
The client may be configured to not enforce negotiation checks on
EXPECTED_OFFER_DATE; if so no EXPECTED_RESP_TIMER attribute (or
EXPECTED_RESP_TIMER set to infinite) should be included in the
quotation order.
Boucadair & Jacquenet Expires November 30, 2013 [Page 28]
Internet-Draft CPNP May 2013
Once the request is sent to the server, the state of the request is
set to "CPQOSent" and a timer, if a response time is included in the
quotation order, is set to the expiration date as included in the
PROVISION request. The client also maintains a copy of the extended
transport session details used to generate the PROVISION request.
The CPNP client must listen on the same port number that it used to
send the PROVISION request.
If no answer is received from the server before the retransmission
timer expires (i.e., RETRANS_TIMER), the client proceeds to
retransmission until maximum retry is reached (i.e., 3 times).
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_ORDER_IDENTIFIER information. If the client does not accept
the expected offer date 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_DATE, it changes the
state of the order to "ServerProcessing" and sets a timer to the
value of EXPECTED_OFFER_DATE. If no offer is made before the timer
expires, the client changes the state of the order to "Cancelled".
If an OFFER message matching the extended CPNP session is received,
the client checks if a PROCESSING message having the same
PROVIDER_ORDER_IDENTIFIER has been received from the server. If a
PROCESSING message was already received for the same order but the
PROVIDER_ORDER_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_ORDER_IDENTIFIER was
already received and matches the CPNP transaction identifier, the
client changes the state of the order to "OfferReceived" and sets a
timer to the value of VALIDITY_DATE 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.
Boucadair & Jacquenet Expires November 30, 2013 [Page 29]
Internet-Draft CPNP May 2013
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.
10.1.2. 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 10.1.1.
If no ACK is received from the server, the client proceeds with the
re-transmission of the message.
10.1.3. 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 10.1.1. 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 10.1.1.
10.2. Server Behavior
10.2.1. Order Processing
Upon receipt of a PROVISION 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 (
Section 9), 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 date 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 date expires.
If the server cannot honor the request, it sends backs a FAIL message
with the appropriate error code.
Boucadair & Jacquenet Expires November 30, 2013 [Page 30]
Internet-Draft CPNP May 2013
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 PROVISION 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 date as well. Once sent to the
client, the server changes the state of the order to "OfferSent" and
a timer set to the validity date 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 CPQO(s) and will behave as a CPNP client to
negotiate child CPQO(s) with possible partnering providers (see
Figure 4).
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 date
expires, the server proceeds with validation checks as specified in
Section 9. The state of the corresponding order is passed to
"AcceptReceived". The server sends back an ACK message to terminate
the order processing cycle.
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".
10.2.2. 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 9.
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.
Boucadair & Jacquenet Expires November 30, 2013 [Page 31]
Internet-Draft CPNP May 2013
10.2.3. 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 9.
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 10.1.1. The server should generate a new Nonce value to
be included in the offer made to the client.
11. 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: PROVISION
2: PROCESSING
3: OFFER
4: ACCEPT
5: DECLINE
6: ACK
7: CANCEL
8: WITHDRAW
9: UPDATE
A register for CPNP errors should be created. The following codes
are reserved:
1: Validation Error
2: Authentication Required
3: Administratively prohibited
4: Out of Resources
5: Network Presence Error
12. 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.
Boucadair & Jacquenet Expires November 30, 2013 [Page 32]
Internet-Draft CPNP May 2013
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.
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.
13. References
13.1. 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.
13.2. Informative References
[I-D.boucadair-connectivity-provisioning-profile]
Boucadair, M., Jacquenet, C., and N. Wang, "IP/MPLS
Connectivity Provisioning Profile", draft-boucadair-
connectivity-provisioning-profile-02 (work in progress),
September 2012.
[I-D.sin-sdnrg-sdn-approach]
Boucadair, M. and C. Jacquenet, "Software-Defined
Networking: A Service Provider's Perspective", draft-sin-
sdnrg-sdn-approach-02 (work in progress), April 2013.
[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
Boucadair & Jacquenet Expires November 30, 2013 [Page 33]
Internet-Draft CPNP May 2013
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.
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
Boucadair & Jacquenet Expires November 30, 2013 [Page 34]